S5-H6: Leakage current suppression in InGaaS-channel MOSFETs: Recessed InP source/drain spacers and InP channel caps

Because InGaAs has a small bandgap, InGaAs MOSFETs are vulnerable to large band-to-band tunneling currents, arising near the drain end of the channel. This sets a minimum off-state leakage current, and can render the device unsuitable for VLSI applications at sub-10-nm gate lengths. Here we report two techniques to reduce band-to-band tunneling leakage in InGaAs MOSFETs. By using either a recessed InP wide bandgap spacer in the regrown source/drain region or, alternatively, an InP channel cap on top of InGaAs channel, off-state leakage can be reduced to 1 nA/μm for 22 nm gate length devices. These two techniques pave the way for application of III-V InGaAs MOSFETs in low power logic.