Semiconductor device and manufacturing method thereof

Abstract

Gate trenches 108 are formed in a memory cell region M using a silicon nitride film 103 as a mask in a state in which the semiconductor substrate 100 in a P-type peripheral circuit region P and an N-type peripheral circuit region N is covered by a gate insulating film 101 s, a protective film 102 , and the silicon nitride film 103 . A gate insulating film 109 is then formed on the inner walls of the gate trenches 108 , and a silicon film 110 that includes an N-type impurity is embedded in the gate trenches 108 . The silicon nitride film 103 is then removed, and a non-doped silicon film is formed on the entire surface, after which a P-type impurity is introduced into the non-doped silicon film on region P, and an N-type impurity is introduced into the non-doped silicon film on regions M and N.

Description

technical field [0001] The present invention relates to a semiconductor device and a manufacturing method thereof, in particular to a semiconductor device with a trench gate transistor and a double gate transistor and a manufacturing method thereof. Background technique [0002] In recent years, the miniaturization of DRAM (Dynamic Random Access Memory) cells is always accompanied by shortening the gate length of memory cell transistors. However, as the gate length shortens, the short-channel effect in transistors becomes more serious, and there is a problem of increased subthreshold current. When the substrate impurity concentration is increased to minimize the short channel effect, deterioration of refresh characteristics in DRAM due to increase in junction leakage becomes a serious problem. [0003] In order to solve these problems, attention has been paid to a so-called trench gate transistor (also called a recess type transistor), which means that a gate electrode is e...

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Problems solved by technology

Because there is interference of a high-resistance film between the doped silicon film 304a and the non-doped silicon film 304b, the gate resistance increases

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