Semiconductor device and method for production thereof

Abstract

A recess (21) is formed in a pMOS region (2). An SiGe layer (22) is formed so as to cover the bottom surface and the side wall of the recess (21). An SiGe layer (23) having a lower Ge content than that in the SiGe layer (22) is formed on the SiGe layer (22). An SiGe layer (24) is formed on the SiGe layer (23).

Description

technical field [0001] The present invention relates to a semiconductor device capable of high-speed operation and its manufacturing method. Background technique [0002] In LSI (large-scale integration: large-scale integration) such as transistors with a process rule of 90nm node or later, the standby leakage current (off-leak current) decreases with the miniaturization of components. cannot be ignored. Therefore, it is difficult to improve the device performance only by simply miniaturizing the gate length of the transistor, and a new attempt to improve the device performance is required. [0003] In such an ultra-miniaturized transistor, the area of ​​a channel region located directly under the gate electrode is very small compared with conventional transistors. It is well known that in such a case, the mobility of carriers (electrons and holes) moving in the channel region is greatly affected by the stress applied to the channel region. Therefore, attempts have been m...

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Problems solved by technology

However, in order to make the thickness of the SiGe layer below the limit film thickness, it is necessary to make the groove shallow, and it is difficult to generate sufficient compressive strain in the channel region.

[0008] Therefore, in the prior art, in order to ensure normal operation, the Ge content was kept low.

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