JPH01115168A - Manufacture of semiconductor light-receiving element - Google Patents

Abstract

PURPOSE:To prevent a local breakdown by a method wherein, after the ions of an impurity, which does not contribute as a dopant, are implanted, the ions of an impurity, which is turned into a dopant, are implanted in a position deeper than that of the impurity which does not contribute as a dopant, then an annealing treatment is performed to form guard rings. CONSTITUTION:The ions (argon ions) 3 of an impurity, which does not contribute as a dopant, are implanted and thereafter, the ions (beryllium ions) 5 of an impurity, which is turned into a dopant, are implanted in a position deeper than that of the impurity which does not contribute as a dopant. Then, an annealing treatment is performed to form guard rings 6. Accordingly, as the diffusion rate of the impurity implanted as a dopant is quick in the vicinity of the surface, whose crystallizability is broken by the implantation of the ions 3 of an impurity which does not contribute as a dopant, the impurity spreads greatly in the vicinity of the surface and as the diffusion rate is slow in a part, whose crystallizability is kept, the impurity spreads little in the part. Thereby, a local breakdown due to a matching shifting can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a semiconductor light receiving element used in optical communication, optical information processing, etc.

(Prior Art) Compound semiconductor photodetectors are being put into practical use as high-sensitivity photodetectors for optical communications and optical information processing. In particular, avalanche photodiodes (hereinafter referred to as APDs) have an internal current gain due to avalanche multiplication of electrons or holes in the vicinity of the breakdown voltage, and are therefore excellent in that they have high light-receiving sensitivity. On the other hand, InGaAs is widely used as a material for semiconductor light-receiving elements for wavelengths of 1-551tIn for high-capacity, long-distance optical communications. InGa manufactured by conventional methods
Figure 2 shows an example of the structure of an As-based APD.
D has a guard ring 6 around the light receiving part in order to prevent local breakdown around the light receiving part 8 and achieve uniform multiplication within the light receiving surface. In order to prevent breakdown, a guard ring 7 with a lower concentration is formed on the outer periphery of the guard ring 6, and the curvature of the guard ring is relaxed. It is used.

(Problems to be Solved by the Invention) In the conventional example described above, the guard ring is formed by two ion implantations with different acceleration energies. In this case, it is necessary to form an implantation mask, and the alignment of the implantation mask requires a high accuracy of 3-3 or less. However, it is not easy to align the injection mask with an accuracy of 3 or less, and APDs obtained by conventional methods are prone to local breakdown due to misalignment.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a semiconductor light-receiving element, which eliminates such conventional drawbacks and can form a guard ring in a simple process to obtain uniform multiplication within the light-receiving surface.

(Means for Solving the Problems) Means provided by the present invention to solve the above-mentioned problems is a method for manufacturing a semiconductor light-receiving element having a guard ring, in which ions of impurities that do not contribute as dopants are implanted. After that, ions of an impurity serving as a dopant are implanted to a deeper position than the impurity that does not contribute as a dopant, and then an annealing treatment is performed to form a guard ring.

(Function) According to the present invention, near the surface where the crystallinity has been destroyed by the ion implantation of impurities that do not contribute as a dopant, the diffusion rate of the impurity implanted as a dopant is fast, so it spreads greatly, and in the area where the crystallinity is maintained, the diffusion rate is reduced. It's slow so there's not much spread.

Therefore, according to the method of the present invention, in addition to obtaining a GR with a relaxed curvature by forming the mask twice, it is also possible to reduce the number of implantation mask steps, and prevent local breakdown due to misalignment. be able to.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a manufacturing method according to an embodiment of the present invention.
a) to (e) are cross-sectional views of structures formed in the guard ring forming step of the method. In the method of this embodiment, first, as shown in FIG. 1(a), an n--InP layer 1
Next, as shown in Figure 1(b), argon ions are implanted at an energy of 70 KV/cTrl to destroy the crystallinity of the surface of the n''-InP.
After approximately 5,000 510t ion implantation masks 4 are formed on the main layer 1 by the VD method, a photoresist 2 is applied. Then, a guard ring pattern is exposed and developed, and the ion implantation mask shown in FIG. 1(c) is formed except for the Si film 4. As shown in the first U5A(d), ions for the guard ring are implanted by implanting Be+ ions 5 at an energy of 10 KV/cm.

Finally, 20ml annealing is performed at 700°C. In this annealing, Be"5 diffuses at a high rate near the surface where the crystallinity has been destroyed by argon ions, and the diffusion rate is slow in the areas where the crystallinity is maintained. Therefore, by annealing, a GR guard ring 6 with a relaxed curvature as shown in FIG. is recovered, so there is no effect on the device characteristics.

(Effects of the Invention) As explained above, according to the manufacturing method of the present invention, a guard ring with a relaxed curvature can be formed using one implantation mask, and local breakdown due to misalignment of the implantation mask can be formed. It is possible to manufacture a semiconductor light-receiving element in which this phenomenon does not occur.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a GR forming step in a method for manufacturing a semiconductor light-receiving device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing an APD manufactured by a conventional method. 1.=n--InP layer, 2... photoresist, 3.
...Argon ion, 4...Sin, membrane, 5...Beryllium ion (Be"), 6...Guard ring, 7
... Guard ring, 8... Light receiving part, 9... P side electrode, 10... Insulating film, 11 = n-InP layer, 12
-n-InGaAsP1! , 13...n-In
GaAs layer, 14= n-InP buffer layer, 15=
n -InP base, 16·-n side electrode.

Claims (1)

[Claims] In a method for manufacturing a semiconductor light receiving element having a guard ring, after implanting impurity ions that do not contribute as a dopant, implanting impurity ions that will become a dopant to a deeper position than the impurity that does not contribute as a dopant, and then annealing. A method for manufacturing a semiconductor light-receiving element, the method comprising forming a guard ring through processing.