Trench type metal oxide semiconductor schottky barrier transistor preparation method

Abstract

The invention relates to a method for preparing TMBS, comprising: providing a semiconductor structure, the semiconductor structure includes a silicon substrate and a silicon oxide layer formed on the surface of the silicon substrate, an etching window is defined on the silicon oxide layer; an etching silicon oxide layer forming process The etching step includes: step A: placing the semiconductor structure in the reaction chamber; step B: filling the first etching gas and adjusting the radio frequency power to the first power to etch the silicon oxide layer. The first power is greater than 400W; step C: before the silicon oxide layer is completely etched, adjust the RF power to the second power, and continue etching the silicon oxide layer until the silicon oxide layer is completely etched to form a process hole, the second power is less than the first power ; Etching the silicon substrate below the process hole and forming TMBS. In the above preparation method, the etching of the silicon oxide layer is divided into two stages and the radio frequency power is reduced in the second stage, thereby reducing the damage to the silicon surface, and the obtained TMBS has better performance.

Description

technical field

[0001] The invention relates to the field of semiconductor technology, in particular to a method for preparing a trench type metal oxide semiconductor Schottky barrier transistor. Background technique

[0002] Compared with traditional Schottky rectifier devices, Trench MOS Barrier Schottky barrier transistor (Trench MOS Barrier Schottky, TMBS) has lower reverse leakage current and higher reverse breakdown voltage, That is, TMBS has better forward conduction and reverse blocking characteristics. Such as figure 1 As shown, the TMBS die includes a semiconductor structure, the semiconductor structure is based on a silicon substrate 110, an oxide layer 120 is formed on the silicon substrate, and then the middle oxide layer is etched away by an etching process to form a process hole 121 To expose the silicon substrate, then etch the silicon below the process hole to form a trench, deposit a gate oxide layer 111 on the inner wall of the trench and fill the trench...

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