Method of manufacturing silicon carbide semiconductor device

Abstract

The present invention provides a method of manufacturing a silicon carbide semiconductor device. In the method of manufacturing the silicon carbide semiconductor device that is a silicon carbide diode having a JBS structure including a mixture of a Schottky junction and a pn junction and that maintains low forward voltage through a SBD structure and enhances surge current capability, nickel silicide films (33) are formed in an oxide film (51) by self-alignment by causing a semiconductor substrate (30) and a metal material film (52) to react with one another through two sessions of heat treatment including a low-temperature heat treatment and a high-temperature heat treatment, the metal material film including sequentially a first nickel film (58), an aluminum film (53), and a second nickel film (54), the first nickel film being in contact with an entire area of a connecting region (20a) of a FLR and p-type regions (21) and (13) respectively exposed in openings (51a, 51b) of the oxide film (51).

Description

technical field [0001] The present invention relates to a method of manufacturing a silicon carbide semiconductor device. Background technique [0002] In recent years, silicon carbide (SiC) semiconductors have attracted attention as semiconductor materials capable of fabricating (manufacturing) semiconductor devices (hereinafter referred to as silicon carbide semiconductor devices) exceeding the limit of semiconductor devices using silicon (Si) semiconductors. In particular, silicon carbide semiconductors are expected to be applied to semiconductor devices with high withstand voltage (for example, 1700 V or higher) due to their advantages of higher breakdown electric field strength and higher thermal conductivity than silicon semiconductors. [0003] In the case where the silicon carbide semiconductor device is a diode (hereinafter referred to as a silicon carbide diode), due to the configuration n - type drift region n - The design specifications of the type epitaxial la...

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Problems solved by technology

Thus, in Figure 23 In the shown conventional silicon carbide semiconductor device 140', similar to the diode of the JBS structure using a silicon semiconductor, in the p-type region 113 and the n-type region 113, - In the drift region 112, the surge current rises due to the bipolar action of the pn junction formed on the front surface of the semiconductor substrate 130. It is estimated that the amount of extraction of the surge current becomes larger, but the effect is not significant.

[0014] Figure 23 One of the important factors for the small amount of surge current extracted in the conventional silicon carbide semiconductor device 140 ′ is that the p-type region 113 and the front electrode 114 that constitute the pn junction of the JBS structure cannot be sufficiently low. Ohmic contact of resistance

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