PSR Silicon Trench Profile Optimization in FinFET Fabrication

In this work a method of PMOS Silicon Recess (PSR) trench profile optimization using silicon oxidation is proposed. TCAD simulations shows that rectangular trench profile is better than two types of U -shaped profile on device performance, such as S/D channel stress 6.2% and 9.2% gaining respectively and Vt 3.6% and 7.1 % gaining respectively. Based on different oxidation rates on crystalline faces between 700°C to 1000 ° C, a silicon oxidation recess (SOR) flow is designed in order to get more rectangular trench profile. Transmission electron microscope (TEM) images shows the SOR method is effective for trench profile optimization, in which anchor pattern 1 and 2 are improved by 69.4% and 46.7% respectively.