JPH06349801A - Surface treatment method - Google Patents

Abstract

PURPOSE:To enable processes such as oxidation, diffusion, thin film deposit, and monocrystal growth to be applied to an Si surface, on which no natural oxide film is formed, by improving the film quality and the like of a thermal oxide film, thin film, and monocrystal to be formed on a semiconductor substrate and by raising the diffusion efficiency of impurity diffusion. CONSTITUTION:A natural oxide film 202 is formed on an Si substrate 201. After a sample is cleaned in a chemical solution and its metallic contaminants are removed, the sample is immersed in an aqueous solution of 0.5% hydrofluoric acid to eliminate the natural oxide film 202. Microwave discharge of iodine gas is made and a generated iodine atom is conveyed to the sample. By performing this treatment for 10 minutes, H is eliminated by an action expressed by H+I HI , and the surface of the Si substrate 201 is coated by iodine(I). This enables processes such as oxidation, diffusion, thin film deposit, and monocrystal growth to be applied onto Si on which no natural oxide film is formed, thus making it possible to increase the quality of a formed film, and performing diffusion uniformly at high concentration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor element manufacturing technique, and more particularly, to a method for oxidizing a semiconductor device after removing a natural oxide film.
The present invention relates to a surface treatment method for performing processes such as diffusion, thin film deposition, and single crystal growth.

[0002]

2. Description of the Related Art A semiconductor, for example, a natural oxide film on the surface of Si causes problems such as deterioration of the film quality of an oxide film or single crystal Si formed on the oxide film, or inhibition of impurity diffusion. Currently, hydrofluoric acid immersion, hydrogen fluoride gas exposure, H
₂ Natural oxide film removal treatments such as plasma etching are widely used, but the Si surface subjected to these treatments is almost covered with hydrogen. Since hydrogen terminated on the Si surface is stable at room temperature, the hydrogen-terminated surface is unlikely to reoxidize at room temperature. However, when heated to 400 to 600 ° C., this hydrogen is removed. Therefore, even if the surface is stabilized by hydrogen termination, for example, oxidation, diffusion,
When the temperature is raised to perform processes such as thin film deposition and single crystal growth thereafter, and the Si surface reaches 400 ° C. or higher, H is removed, and active Si appears along with it, and a slight amount of residual Si remains in the atmosphere. Oxygen or water causes reoxidation.

[0003]

As described above, Si
When natural oxide film removal and surface hydrogen termination are performed as pretreatments for processes such as oxidation on the surface, diffusion, thin film deposition, and single crystal growth, hydrogen is removed during the temperature rising process and the activity However, there is a problem that re-oxidation occurs due to the reaction of various Si with residual oxygen and water.

The present invention solves the above problems, and an object thereof is to provide a surface treatment method for subjecting a Si surface on which a natural oxide film is not formed to processes such as oxidation, diffusion, thin film deposition, and single crystal growth. To do.

[0005]

In order to achieve the above object, in the first aspect of the present invention, a natural oxide film formed on a semiconductor substrate is removed by a substance containing hydrogen, and the semiconductor surface is terminated with hydrogen. And a step of removing hydrogen terminating the semiconductor substrate surface with hydrogen by a substance containing at least one halogen element of iodine or bromine, and terminating the surface with the halogen element, And a step of removing the halogen element terminating the surface of the semiconductor substrate.

In a second aspect of the present invention, a step of removing the natural oxide film formed on the semiconductor substrate with a substance containing hydrogen and fluorine and terminating the surface of the semiconductor substrate with hydrogen and fluorine, and including hydrogen. A step of removing fluorine terminating the surface of the semiconductor substrate with a substance and terminating the entire surface with hydrogen; and a step of hydrogenating the surface of the semiconductor substrate with a substance containing at least one halogen element of iodine or bromine. There is provided a surface treatment method including a step of removing terminating hydrogen and terminating the surface with the halogen element, and a step of removing the halogen element terminating the surface of the semiconductor substrate.

Preferably, the halogen element terminating the surface of the semiconductor substrate is removed by irradiating the surface of the semiconductor substrate with light. Further, it is preferable that the semiconductor substrate is heated to a substrate temperature of 400 ° C. or higher to remove the halogen element terminating the surface of the semiconductor substrate.

Further, the step of removing the natural oxide film formed on the semiconductor substrate with a substance containing hydrogen and terminating the semiconductor surface with hydrogen is performed by dipping in a solution containing HF,
Overexposure to gas containing HF, gas containing fluorine and NH ₃
Desirably, any one of down-flow etching using a gas containing H, down-flow etching using SF ₆ gas and H ₂ O gas, exposure to a gas containing H atoms, and plasma etching of a gas containing H _2. .

[0009]

According to the surface treatment method of the present invention, the natural oxide film formed on the surface of the semiconductor substrate is removed, the hydrogen terminating the substrate surface is removed, and the surface is terminated with iodine instead. Therefore, it is possible to prevent the natural oxide film from being formed again on this surface. Therefore, when various processes are performed on the surface of the semiconductor substrate, the quality of the thermal oxide film, the thin film, and the single crystal film formed on the semiconductor substrate is improved, and the diffusion efficiency of impurity diffusion is increased. Is possible.

[0010]

Embodiments of the present invention will be described with reference to the drawings. Example 1 FIG. 1 is a schematic view of an apparatus used in an example of the surface treatment method of the present invention. As shown in FIG. 1, 111 is a pretreatment chamber and 121 is a reaction chamber. After the sample 141 placed on the sample table 151 is processed in the processing chamber 111, it is exposed to the atmosphere by a sample transfer means (not shown). Valve 1 without
It can be conveyed to the reaction chamber via 31 and processed.

In the pretreatment chamber 111, the gas introduction port 112
The gas is introduced from (a), exhausted from the gas exhaust port 113, and 2.45 GHz generated by the microwave power source 118.
The microwave of z is transmitted through the waveguide 117 to the cavity 11
6 is applied to the gas inlet 112 (b) to
The gas introduced into the discharge tube 115 made of N is microwave-discharged, and the generated active species is sampled by the gas disperser 114.
51 can be uniformly supplied. 119 is a heater, which can heat the sample 141 to 200 ° C.

Also in the reaction chamber 121, the gas inlet 12
Gas can be introduced from 2 (a) and exhausted from the gas exhaust port 123, and 2.45 generated by the microwave power source 128
By applying a microwave of GHz to the cavity 126 via the waveguide 127, the gas introduced into the BN discharge tube from the gas inlet 122 (b) is subjected to microwave discharge, and the generated active species are gas-discharged. The sample 14 is dispersed by the disperser 124.
1 can be uniformly supplied. Further reaction chamber 121
With the heater 129, the sample 141 can be heated to 1000 ° C., and processing such as oxidation, diffusion, thin film deposition, and single crystal growth can be performed.

Further, although not shown, the gas disperser 11
W heaters are wound around 4,124 and the gas inlet 11
The gas introduced from 2 (b) and 122 (b) can also be thermally decomposed and supplied to the sample.

2 (a) to 2 (d) are process sectional views showing an embodiment of the surface treatment method according to the present invention. The apparatus used in this embodiment is the one shown in FIG. In this example, a process for forming a Si thermal oxide film will be described.

First, the natural oxide film 202 is formed on the Si substrate 201.
The sample shown in FIG. 2 (a) formed above is washed with a chemical solution to remove metal contaminants and organic contaminants, and then immersed in a 0.5% hydrofluoric acid aqueous solution to remove the natural oxide film 202. Further, it was washed with pure water having a dissolved oxygen of 5 ppb or less for 10 minutes. As a result, the surface of the Si substrate 201 was terminated with hydrogen (H) as shown in FIG. 2 (b).

This sample was immediately placed in the pretreatment chamber 111 of the apparatus shown in FIG. 1, and after evacuation from the gas exhaust port 113, the iodine crystal was heated to 50 ° C., which was generated at 0.1 Torr. Elementary vapor gas inlet 112
In (b), a microwave of 100 W was applied to the cavity 116 to generate a microwave discharge of iodine gas, and the generated iodine atoms were transported to the sample 141. By performing this treatment for 10 minutes, H was removed by H + I → HI ↑, and the surface of the Si substrate 201 was covered with iodine (I) as shown in FIG. 2 (c).

This sample 141 was conveyed to the reaction chamber 121 whose inside was replaced with Ar, through a valve 131, without exposing the surface to the atmosphere, and heated to 900 ° C. in an Ar atmosphere. At this time, I was still bonded on the Si substrate 201, and reoxidation due to residual oxygen and residual moisture in the reaction chamber 121 did not occur at all. Next, the gas inlet 122
From (b), H ₂ gas of 0.1 Torr was introduced, and a microwave of 100 W was applied to the cavity 116 to generate a microwave discharge of hydrogen gas.
Transported to 1. This process is performed for 1 minute, and I is I + H →
After removing by HI ↑, O is introduced from the gas inlet 122 (a).
₂ gas is introduced, and as shown in FIG.
A 5 nm thermal oxide film 203 was formed on top of this.

When the dielectric breakdown voltage of the thermal oxide film 203 thus formed is measured, 95% or more is 10 Me.
It showed a breakdown voltage of V or more. On the other hand, 80% of the samples that did not undergo iodine termination treatment exhibited a withstand voltage of 10 MeV or higher. As described above, by using the present invention, it is possible to form a thermal oxide film on a clean Si substrate surface without causing reoxidation at the time of temperature rise for oxidation, high dielectric breakdown voltage, and high quality. A thermal oxide film could be formed.

Embodiment 2 FIGS. 3A to 3E are process sectional views showing an embodiment of the surface treatment method according to the present invention. The apparatus used in this embodiment is the one shown in FIG. This example describes epitaxial growth of Si.

First, the natural oxide film 302 is formed on the Si substrate 301.
The sample shown in FIG. 3 (a) formed above was washed with a chemical solution to remove metal contaminants and organic contaminants. Then, Figure 1
It was placed in the pretreatment chamber 111 of the apparatus shown in FIG.
Next, NF ₃ = 100 sccm, NH ₃ = 300 sccm
Is introduced from the gas introduction port 112 (b), and the pressure in the pretreatment chamber is maintained at 0.3 Torr, and 10
After applying a microwave of 0 W and holding it for 5 minutes, the gas supply was stopped and the chamber was evacuated again.
Sample 141 was heated to 100 ° C. and held for 10 minutes. By this processing, the natural oxide film 302 on the surface of the Si substrate 301
Is SiO ₂ + 6NH ₄ F → (NH ₄ ) ₂ SiF ₆ + 2H
₂ O + 4NH ₃ , (NH ₄ ) ₂ SiF ₆ → 2NH ₃ +2
It was removed by the reaction of HF + SiF ₄ , and the surface of the Si substrate was covered with H and F as shown in FIG. 3 (b).

Next, 100 sccm of H ₂ gas is supplied from the gas inlet 112 (a), and Ar gas 3 is supplied from the gas inlet 112 (b).
Introducing 00 sccm, the pretreatment chamber pressure is 0.1 Torr
While maintaining at r, a microwave of 200 W was applied to the cavity 116 and kept for 10 minutes. By this treatment, metastable Ar generated by microwave discharge reacts with H _{2 in the} pretreatment chamber, and H atoms generated by the decomposition of H ₂ generate F on the Si substrate surface as HF or SiF _x H _y. As a result of removal,
The surface of the Si substrate 301 is entirely H as shown in FIG. 3 (c).
Covered with.

After evacuating the inside of the pretreatment chamber 111 and transporting the sample 141 to the evacuated reaction chamber 121, 100 sccm of I ₂ gas from the gas inlet 122 (a) and Ar from the gas inlet 122 (b). A gas of 300 sccm was introduced, and a microwave of 200 W was applied to the cavity 126 for 10 minutes while maintaining the pressure of the reaction chamber at 0.1 Torr. By this treatment, metastable Ar generated by microwave discharge reacts with I _{2 in the} reaction chamber, and I atoms generated by decomposition of I ₂ remove H on the Si substrate surface as HI. As a result, Si substrate 301 The surface of the sample was entirely covered with I as shown in FIG. 3 (d).

This sample 141 is heated by a heater 129 and heated to 500 ° C. or higher, for example, 600 ° C., then H ₂ gas 100 sccm is supplied from the gas inlet 122 (a) and Ar gas 300 sccm is supplied from the gas inlet 122 (b). After the introduction, while maintaining the pressure in the reaction chamber at 0.1 Torr, a microwave of 200 W was applied to the cavity 126 and kept for 2 minutes. By this treatment, metastable Ar generated by microwave discharge reacted with H _{2 in the} reaction chamber, and H atoms generated by the decomposition of H ₂ removed I on the Si substrate surface as HI. Next, while maintaining the sample temperature at 600 ° C., SiH ₄ gas was introduced from the gas inlet 122 (a) to epitaxially grow Si (303) on the Si substrate 301 as shown in FIG. 3 (e).

The epitaxial Si 303 grown in this manner had no defects or dislocations, and no oxygen was found at the interface between the substrate Si and the epitaxial Si even after impurity analysis. On the other hand, in the state of FIG.
Defects and dislocations were observed, and oxygen was detected at the interface between the substrate Si and the epitaxial Si. As described above, by using the present invention, it was possible to epitaxially grow high-quality Si without defects or dislocations.

Embodiment 3 FIGS. 3 (a) to 3 (d) are process sectional views showing an embodiment of the surface treatment method according to the present invention. The apparatus used in this embodiment is the one shown in FIG.

In this example, a process for forming a Si thermal oxide film will be described. First, the natural oxide film 202 is formed on the Si substrate 201.
The sample shown in FIG. 3 (a) formed above was washed with a chemical solution to remove metal contaminants and organic contaminants.

Then, the pretreatment chamber 111 of the apparatus shown in FIG.
Put in, it was evacuated from the gas exhaust port 113, NH ₄
The gas generated by heating the F powder to 100 ° C. is introduced into the pretreatment chamber through the gas inlet 112 (a) (0.01
Torr) and hold for 5 minutes. After the gas supply was stopped and the chamber was evacuated again, the sample 141 was heated to 100 ° C. by the heater 119 and held for 10 minutes. By this treatment, the natural oxide film 302 on the surface of the Si substrate 301 is changed to SiO ₂
+ 6NH ₄ F → (NH ₄ ) ₂ SiF ₆ + 2H ₂ O + 4N
H ₃ , (NH ₄ ) ₂ SiF ₆ → 2NH ₃ + 2HF + Si
It is removed by the reaction of F ₄ , and as shown in FIG.
The surface of the substrate was covered with H and F.

Next, from the gas inlet 112 (b), H ₂ gas 1
00 sccm was introduced, and the W heater wound around the gas disperser 114 was energized. As a result, H ₂ is thermally decomposed, and the generated H atoms remove F from the surface of the Si substrate as HF or SiF _x H _y. As a result, the surface of the Si substrate 301 is entirely H as shown in FIG. 3 (c). Covered

This sample 141 was conveyed to the reaction chamber 121 whose inside was replaced with Ar through the valve 131 without passing its surface to the atmosphere, and then iodine gas was introduced from the gas inlet 122 (a). Then, the temperature of the sample was raised to 600 ° C. while maintaining the reaction chamber at 0.1 Torr. S in this process
Hydrogen on the surface of the i-substrate 201 is desorbed, and the generated active Si reacts with I _{2. As} shown in FIG.
Was covered with I.

Next, after raising the temperature of the sample to 900 ° C., 100 sccm of H ₂ gas was introduced from the gas inlet 122 (b), and the W heater wound around the gas disperser 124 was energized. This treatment is performed for 1 minute to remove I on the surface of the Si substrate as HI by H atoms generated by thermal decomposition, and then O ₂ gas is introduced from the gas introduction port 122 (a) to the Si substrate 201 to a thickness of 3 nm. Thermal oxide film (not shown) was formed.

When the dielectric breakdown voltage of the thermal oxide film 203 thus formed was measured, 98% or more was 8 MeV.
The above breakdown voltage was shown. On the other hand, 70% of the samples that did not undergo iodine termination treatment exhibited a breakdown voltage of 8 MeV or higher. As described above, by using the present invention, a thermal oxide film can be formed on a clean Si substrate surface without causing re-oxidation at the time of temperature rise for oxidation, high dielectric breakdown voltage and high quality. A thermal oxide film could be formed.

Embodiment 4 FIG. 4 is a schematic view of an apparatus used in an embodiment of the surface treatment method of the present invention. As shown in FIG. 4, it is composed of a pretreatment chamber 411 and a reaction chamber 421, and the sample 441 is transported between the pretreatment chamber 411 and the reaction chamber 421 via a valve 431 without being disturbed by the atmosphere. You can

A heater 415 is embedded in the pretreatment chamber 411, and a sample stand 414 and a window 416 to which a high frequency of 13.56 MHz can be applied are provided.
Further, heating up to 1000 ° C., light irradiation, plasma etching and the like can be performed. A discharge tube 417 made of alumina or BN is connected to the pretreatment chamber 411, and 2.45G generated by the microwave power source 420 is generated.
Cavity 4 through the waveguide 419
18, the gas introduced from the gas inlet 412 is discharged, and the generated active species is discharged to the pretreatment chamber 411.
Sample 441 can be transported. Pretreatment room 41
The gas introduced into the No. 1 is exhausted from the gas exhaust port 413. The reaction chamber 421 is also provided with a sample table 424 in which a heater 425 is embedded, a window 426, a gas introduction port 422, and a gas exhaust port 423.
Heating in a vacuum or gas or light irradiation can be performed.

5 (a) to 5 (e) are process sectional views showing an embodiment of the surface treatment method according to the present invention. The apparatus used in this embodiment is the one shown in FIG. In this example, the step of burying TiSi _{2 in} the contact hole will be described.

First, as shown in FIG. 5A, a Si substrate 51
A CVD oxide film 52 having a thickness of 1 μm is deposited on the above, and a contact hole 54 having an opening diameter of 1 μm is opened by photolithography and RIE (reactive ion etching) using CF ₄ / H ₂ gas to diffuse impurities. The diffusion layer 53 was formed. A natural oxide film 55 was formed on the surface of the Si substrate 51 at the bottom of the contact hole 54.

This sample is put in a pretreatment chamber 41 of the apparatus shown in FIG.
1 and vacuum evacuation, then from the gas inlet 412 to SF
₆ / H ₂ O mixed gas (partial pressure 2.5 Torr / 0.5 To
rr) was introduced, a microwave of 100 W was applied to the cavity 418 and stored for 10 minutes, the natural oxide film 55 at the bottom of the contact hole 54 was removed, and the Si surface was formed as shown in FIG.
As shown in (b), it was covered with H, F, S, etc.

Next, the gas introduced from the gas inlet 412 is changed to H ₂ gas, and the pressure in the pretreatment chamber 411 is adjusted to 0.1 To.
A microwave of 100 W was applied to the cavity 418 while kept at rr and kept for 10 minutes, and the bottom of the contact hole 54 was covered with H as shown in FIG. 5 (c).

Next, the sample was irradiated with SOR light (peak energy 25 eV) from the window 416 while introducing 0.5 Torr of iodine gas through the gas inlet 422. By this treatment, part of H on Si at the bottom of the contact hole 54 is directly desorbed by light irradiation, and part of it is I ₂
It is extracted and removed by the I atom generated by the photolysis of the gas, and the contact hole 54 is removed as shown in FIG. 5 (d).
The surface of the bottom Si substrate 1 was covered with I.

After being transferred to the reaction chamber 421 whose interior is evacuated, the temperature of the sample is raised to 700 ° C. by the heater 425, and 10 sccc of TiCl ₄ gas is supplied from the gas inlet 422.
m, SiH ₄ gas of 100 sccm was introduced and the pressure in the process chamber 421 was kept at 0.1 Torr for 15 minutes. As a result, as shown in FIG. 5 (e), TiSi was selectively removed from the bottom of the contact hole 54. After growth, the contact hole 54 was filled with TiSi ₂ .

The contact resistance of the contact hole thus formed was one digit lower than that of the case where TiSi ₂ was formed without covering the Si surface with I. When analyzed by SIMS, oxygen was not found at the interface between TiSi ₂ and Si in the I-terminated one, but slight oxygen was detected in the H-terminated one. As described above, by using the present invention, it was possible to fill the contact hole with less oxygen at the interface and, as a result, low contact resistance.

Embodiment 5 FIGS. 6A to 6E are process sectional views showing an embodiment of the surface treatment method according to the present invention. The apparatus used in this embodiment is the one shown in FIG. In this embodiment, an impurity diffusion process will be described.

First, the Si substrate 61 as shown in FIG.
The sample on which the native oxide film 62 was formed was placed in the pretreatment chamber 411 of the apparatus shown in FIG. 4, evacuated, then HF gas 50 Torr was introduced from the gas inlet 412 and held for 5 minutes. As shown in FIG. 6 (b), the surface of the Si substrate was covered with H and F.

Next, the sample is heated to 300 ° C., H ₂ gas is introduced at 5 × 10 ⁻⁵ Torr from the gas inlet 412, and 1
After holding for 0 minute, F on the surface of the Si substrate 61 was removed and the entire surface was covered with H as shown in FIG. 6 (c).

This sample was conveyed to the reaction chamber 421, and HI gas was introduced from the gas inlet 422 to maintain the inside at 1 Torr, the sample temperature was raised, and was held at 500 ° C. for 10 minutes. At this time, part of H on the surface of the Si substrate 61 is desorbed, and part of H is generated by thermal decomposition of HI.
And then the Si substrate 61 is removed as shown in FIG. 6 (d).
The Si on the surface of was terminated with I.

Further, after raising the sample temperature to 600 ° C., SOR light (peak wavelength 50 eV) is irradiated from the window 426,
After removing the surface I, B2 H6 from the gas inlet 422
A gas of 1 Torr was introduced and held for 30 minutes. As a result of this treatment, as shown in FIG. 6 (e), B is formed on the surface of the Si substrate 61.
The diffusion layer of was formed. The diffusion layer thus formed had a uniform depth (200 ± 2 nm) and a high B concentration (3 × 10 ²⁰ cm ⁻³ or more). On the other hand, in the case where the temperature was raised and B was diffused without I termination of the surface,
Re-oxidation occurred and diffusion was performed through the natural oxide film formed as a result, so the diffusion layer was uneven (150 ± 8n
The B concentration in m) was as low as 8 × 10 ¹⁹ cm ^-3 . As described above, by using the present invention, it was possible to form a uniform and high-concentration impurity diffusion layer.

The present invention is not limited to the above embodiment. For example, the atom to be terminated after the hydrogen atom may be another halogen atom, especially bromine. In this case, the removal requires a temperature higher than the removal temperature required for iodine. In addition, various modifications can be made without departing from the scope of the present invention.

[0047]

According to the present invention, it is possible to perform processes such as oxidation, diffusion, thin film deposition, and single crystal growth on Si on which a natural oxide film is not formed, thereby improving the quality of the formed film. The diffusion can be performed uniformly and with high concentration.

[Brief description of drawings]

FIG. 1 is a schematic view of a surface treatment apparatus used in an embodiment of a surface treatment method according to the present invention.

FIG. 2 is a process sectional view showing an embodiment of a surface treatment method according to the present invention.

FIG. 3 is a process sectional view showing an embodiment of a surface treatment method according to the present invention.

FIG. 4 is a schematic view of a surface treatment apparatus used in an embodiment of a surface treatment method according to the present invention.

FIG. 5 is a process sectional view showing an embodiment of a surface treatment method according to the present invention.

FIG. 6 is a process sectional view showing an embodiment of a surface treatment method according to the present invention.

[Explanation of symbols]

111, 411 ... Pretreatment chamber 121, 421 ... Reaction chamber 131, 431 ... Valve 141, 441 ... Sample 112 (a), (b), 122 (a), (b), 412, 422 ... Gas inlet 113, 123, 413, 423 ... Gas exhaust port 114, 124 ... Gas disperser 115, 125, 417 ... Discharge tube 116, 126, 418 ... Cavity 117, 127, 419 ... Waveguide 118, 128, 420 ... Microwave power source 119 , 129, 415, 425 ... Heater 201, 301, 51, 61 ... Si substrate 202, 302, 55, 62 ... Natural oxide film 203 ... Thermal oxide film 303 ... Epitaxial Si 414, 424 ... Sample stand 416, 426 ... Window 52 ... CVD oxide film 53, 63 ... Diffusion layer 54 ... Contact hole 55 ... TiSi ₂

Claims (5)

[Claims] 1. A step of removing a natural oxide film formed on a semiconductor substrate with a substance containing hydrogen to terminate the semiconductor surface with hydrogen, and a substance containing at least one halogen element of iodine or bromine. By removing hydrogen terminating the surface of the semiconductor substrate with hydrogen and terminating the surface with the halogen element; and removing the halogen element terminating the surface of the semiconductor substrate. A surface treatment method characterized by the above. 2. A step of removing a natural oxide film formed on a semiconductor substrate with a substance containing hydrogen and fluorine, terminating the surface of the semiconductor substrate with hydrogen and fluorine, and a surface of the semiconductor substrate with a substance containing hydrogen. Of fluorine terminating the surface of the semiconductor substrate with hydrogen and terminating the entire surface with hydrogen, and removing hydrogen terminating the surface of the semiconductor substrate with hydrogen by a substance containing at least one halogen element of iodine or bromine. A surface treatment method comprising the steps of removing and terminating the surface with the halogen element, and removing the halogen element terminating the surface of the semiconductor substrate. 3. The halogen element terminating the surface of the semiconductor substrate is removed by irradiating the surface of the semiconductor substrate with light.
The surface treatment method described. 4. The semiconductor element is heated to a substrate temperature of 400 ° C. or higher to remove the halogen element terminating the surface of the semiconductor substrate. Surface treatment method. 5. The step of removing the natural oxide film formed on the semiconductor substrate with a substance containing hydrogen and terminating the semiconductor surface with hydrogen is performed by dipping in a solution containing HF, HF.
Exposure to a gas containing H, downflow etching using a gas containing a fluorine element and a gas containing NH ₃ , downflow etching using a SF ₆ gas and H ₂ O gas, exposure to a gas containing H atoms, H _3. The surface treatment method according to claim 1, which is a step including any one of plasma etching of a gas containing ₂ .