Taiwan Semiconductor Manufacturing Comp. Ltd.

Ying Hao Hsieh

Syun-Ming Jang Jang

Tze-Liang Lee

Chao-Cheng Chen

Chii-Horng Li

Ming-Hua Yu

Shih-Hao Lo

Eric Peng

A device including a gate stack over a semiconductor substrate having a pair of spacers abutting sidewalls of the gate stack. A recess is formed in the semiconductor substrate adjacent the gate stack. The recess has a first profile having substantially vertical sidewalls and a second profile contiguous with and below the first profile. The first and second profiles provide a bottle-neck shaped profile of the recess in the semiconductor substrate, the second profile having a greater width within the semiconductor substrate than the first profile. The recess is filled with a semiconductor material. A pair of spacers are disposed overly the semiconductor substrate adjacent the recess.

Source/drain recess in a semiconductor device

Bottle-neck recess in a semiconductor device

The present disclosure provides a method for fabricating a semiconductor device that includes providing a silicon substrate, forming a gate stack over the silicon substrate, performing a biased dry etching process to the substrate to remove a portion of the silicon substrate, thereby forming a recess region in the silicon substrate, performing a non-biased etching process to the recess region in the silicon substrate, thereby forming a bottle-neck shaped recess region in the silicon substrate, and epi-growing a semiconductor material in the bottle-neck shaped recess region in the silicon substrate. An embodiment may include a biased dry etching process including adding HeO2 gas and HBr gas. An embodiment may include performing a first biased dry etching process including N2 gas and performing a second biased dry etching process not including N2 gas. An embodiment may include performing an oxidation process to the recess region in the silicon substrate by adding oxygen gas to form silicon oxide on a portion of the recess region in the silicon substrate. As such, these processes form polymer protection to help form the bottle-neck shaped recess.

Growing community of inventors

Hsinchu, Taiwan

Ying Hao Hsieh