Advanced Transistors for Supply Voltage Reduction: Tunneling Field-Effect Transistors and High-Mobility MOSFETS

Abstract

In recent years, metal-oxide-semiconductor field-effect transistors (MOSFETs) have entered the phase of "power-constrained scaling". Tunneling field-effect transistors (TFETs) and high-mobility Ge1-xSnx channel MOSFETs are promising candidates to enable the scaling of transistor supply voltage; therefore, reduction in power consumption of integrated circuits can be achieved. In this thesis, TFETs and Ge1-xSnx MOSFETs are studied. For TFETs, dependence of the tunneling current on temperature and strain was investigated for the first time. TFETs with two novel heterostructures (Si0.5Ge0.5/Si0.989C0.011/Si and Ge/In0.53Ga0.47As) were realized to enhance the tunneling current. For Ge1-xSnx MOSFETs, surface passivation technique using low-temperature Si2H6 treatment was investigated. By optimizing the thickness of the Si passivation layer and post metal annealing conditions, performance improvement of Ge1-xSnx p-channel MOSFETs was achieved.