JPH0325977A - Schottky barrier diode - Google Patents

Abstract

PURPOSE:To reduce a reverse wet current and to stabilize reverse characteristics by controlling the temperature of a semiconductor substrate in a specific range when an aluminum layer is laminated on a barrier metal layer by depositing. CONSTITUTION:An annular P-type layer 13 is formed as a guard ring on the surface of a silicon substrate 1 in which an N-type layer 12 is epitaxially grown on an N<+> type base plate 11. After the surface provided with the ring 13 is covered with an oxide film 2, an opening is opened inside from the center of the ring, and Mo is deposited as a barrier metal layer 3. Further, an Al electrode layer 4 is deposited thereon. When an aluminum layer is deposited on the barrier metal layer, the temperature of a semiconductor substrate is controlled to a range of 210-270 deg.C. The layers 3 and 4 are, after all the surfaces are deposited, so patterned that a peripheral edge is provided above outside the ring 13.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a Schifftky barrier diode in which a Schittky barrier metal layer is in contact with the surface of a semiconductor substrate, and 171 or more electrode metal layers are deposited thereon. Concerning the manufacturing method. [Prior Art] Lamination of a barrier metal layer and an electrode metal layer on a semiconductor substrate of a Shontokey barrier diode is usually performed by successive evaporation in the same vacuum evaporation tank. Conventionally, when depositing barrier metals such as No, the base FL temperature was accurately controlled to 340 to 350°C using radiation heating, and then <,
When depositing the electrode layer and other metal electrode layers laminated as necessary, do not heat the substrate or at most
It was heated to about ℃. [Problems to be Solved by the Invention] Schottky barrier diodes manufactured by depositing barrier metal layers and IT electrode metal layers using conventional methods have a problem in that the reverse characteristics vary greatly between deposition lofts. An object of the present invention is to provide a method for economically manufacturing a Schittky barrier diode with less variation in reverse characteristics between the deposition lofts of the barrier metal layer and the electrode metal layer. [Means for Solving the Problems] In order to achieve the above object, the present invention provides an electrode metal layer in which the layer adjacent to the Schittky barrier metal layer in contact with the surface of a semiconductor substrate is made of aluminum by vapor deposition. In the method for manufacturing a Schittky barrier diode, the barrier gold r! When laminating an aluminum layer on Ayi by vapor deposition, the temperature of the semiconductor substrate shall be controlled within the range of 210 to 270°C. [Function] Variations in the reverse characteristics of Schittky barrier diodes are caused by variations in the degree of adhesion between the semiconductor substrate and the barrier metal layer, between the barrier metal layer and the electrode metal layer, and by the mechanical force between the barrier metal layer and the 1T electrode metal layer. Due to the variation in
According to the present invention, by controlling the semiconductor substrate to an appropriate temperature during vapor deposition of the M electrode layer laminated on the barrier metal layer, the adhesion between the M layer and the barrier metal layer is improved and made uniform. , the mechanical stress between the barrier metal layer and the M layer is reduced and made uniform. Furthermore, the degree of adhesion between the semiconductor substrate and the barrier metal layer is made uniform, which reduces the reverse leakage current and makes the reverse characteristics uniform. [Example] Figures 2 and 3 show two examples of sysaft key barrier diodes in which the present invention is implemented during manufacture. In FIG. 2, an annular p-layer 13 as a guard ring is formed on the surface of a silicon-based film in which N 1i 12 is epitaxially grown on an N 4 motherboard 11 . After covering the surface on which the guard ring 13 is provided with an oxide film 2, an opening is made inside from the center of the guard ring, and the Mo
is vapor-deposited to form barrier metal layer 3. Furthermore, k1 on top of that
Deposit electrode Ji4. After the interlayer 3 and A7N4 are deposited on the entire surface, they are patterned so that the periphery is above the outside of the guard ring l3. In Figure 3, A7tpiJ
Nii4 is added on top of Li4 to prevent alloying of M and Au.
A pole layer 5 and an Au electrode layer 6 with good solderability are laminated. FIG. 1 shows the reverse leakage IT flow of the Schottky barrier diode shown in FIG. 2 and the silicon base 41i. 'iA degree, and when the substrate is held at a temperature lower than 210°C,
Alternatively, if the temperature is maintained at a temperature higher than 270°C, it is observed that the reverse leakage current increases. -Such a relationship is observed when manufacturing a diode with the structure shown in Figure 3, which has three electrode metal layers. The deposition of M layer 4 was also observed. [Effects of the Invention] According to the present invention, when a M1i electrode layer is deposited after a barrier metal layer is deposited on a semiconductor substrate, the adhesion between the barrier metal layer, the M electrode layer, and the semiconductor substrate is improved. The reverse leakage current of the manufactured Schittky barrier diode is reduced by heating the substrate to an appropriate temperature for uniformization and prevention of mechanical stress generation between the barrier metal layer and the M electrode layer. , we were able to stabilize the reverse direction characteristics.

[Brief explanation of drawings]

Fig. 1 is a relationship diagram between the reverse leakage current of a Schottky barrier diode and the semiconductor substrate temperature during the deposition of the M electrode layer, and Fig. 2 is a cross-sectional view of an example of a Schottky barrier diode.
Figure 3 is a cross-sectional view of another example. 1: Silicon substrate, 3: Barrier metal layer, 4: A1 Figure 1! 3 '1!2 Figure 3rd child

Claims (1)

[Claims] 1) In a method for manufacturing a Schottky barrier diode in which an electrode metal layer is formed by vapor deposition in which the layer adjacent to the Schottky barrier metal layer in contact with the surface of a semiconductor substrate is made of aluminum, an aluminum layer is laminated on the barrier metal layer by vapor deposition. When the temperature of the semiconductor substrate is 210~2
A Schottky barrier diode characterized by being controlled within a range of 70°C.