Si0.5Ge0.5 Channel FinFET Preparation on an In Situ Doped SiGe SRB and Its Electrical Characteristics Optimization

Abstract

In this paper, the Si0.5Ge0.5 channel FinFET preparation on an in situ doped SiGe strain relaxed buffer (SRB) and its electrical characteristic optimization were explored in detail. First, an in situ phosphorus doped three-layer SiGe SRB is developed and a perfect Si0.5Ge0.5/Si0.7Ge0.3 SRB fin profile is achieved under the conventional STI last scheme. Then, the Si0.5Ge0.5 channel FinFET is successfully prepared according to the standard integration process of Si channel FinFET. However, it suffers bad electrical performance due to poor Si0.5Ge0.5 channel interfacial property and high S/D series resistance. Therefore, a channel passivation process including an in situ ozone oxidation combined with HfO2/Al2O3 bi-layer gate dielectric, and a S/D silicide process are simultaneously introduced to optimize its electrical characteristics. As a result, its SS can be decreased from 174 to 104 mV/dec, and its driven current under |VGS| = |VDS| = 0.8 V can be increased from 12 to 314 μA/μm. Therefore, these newly developed technologies are practical for the Si0.5Ge0.5 channel FinFET.