(Invited) Record-Performance In(Ga)As MOSFETS Targeting ITRS High-Performance and Low-Power Logic

Abstract

We review recent development of In(Ga)As-channel MOSFETs. Low-effective mass InAs and InGaAs channels, combined with thin gate dielectrics, provide high transconductance, but off-state leakage can be high due to band-band and source-drain tunneling currents. This leakage is reduced through thin 2.5-3nm channels, and through InGaAs or wide-bandgap InP vertical field spacers in the raised, regrown source and drain. Planar UTB devices with 2.7nm thick strained InAs channels and lightly-doped InGaAs spacers in the raised regrown source and drain provide, at 25nm gate length, record 0.5mA/µm on-current at 100nA/µm off-current (ITRS HP specification) and 500mV VDD. 1 µm gate length FETs show 61mV/decade subthreshold swing at 0.1 Volts VDD. Targeting the ITRS LP specification, we have developed InGaAs-channel MOSFETs with lightly-doped InP wide-bandgap spacer layers in the raised source and drain. At 30nm gate length, these show a minimum 60 pA/µm off-current, approximately 100:1 smaller than a similar device using InGaAs source/drain spacers. A FET using InP spacers, with 45 nm gate length, shows 0.15 mA/µm on-current at 1nA/µm off-current (ITRS GP specification) and 500mV VDD. We will discuss ongoing efforts to further increased on-current and decrease off-current in short-gate-length III-V MOSFETs.