Method for forming semiconductor device

• Main Authors: TUNG, YEN-TIEN, CHAN, KUEI-LIN, HUANG, JHIH-RONG, LIN, KENGU, YEN, FU-TING, SHEN, TZER-MIN, LIN, HAN-YU, LIN, LI-TE, LIN, PIN-YEN
• Format: Patent
• Language: Chinese; English
• Published: 01.02.2022
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; SEMICONDUCTOR DEVICES

The present disclosure describes a semiconductor structure and a method for forming the same. The method can include forming a fin structure over a substrate. The fin structure can include a first channel layer and a sacrificial layer. The method can further include forming a first recess structure in a first portion of the fin structure, forming a second recess structure in the sacrificial layer of a second portion of the fin structure, forming a dielectric layer in the first and second recess structures, and performing an oxygen-free cyclic etching process to etch the dielectric layer to expose the channel layer of the second portion of the fin structure. The process of performing the oxygen-free cyclic etching process can include performing a first etching process to selectively etch the dielectric layer over the channel layer of the second portion of the fin structure with a first etching selectivity, and performing a second etching process to selectively etch the dielectric layer over the channel layer o