Scaling and carrier transport behavior of buried-channel In0.7Ga0.3As MOSFETs with Al2O3 insulator

Abstract

In this paper, we investigate the scaling and carrier transport behavior of sub-100nm In0.7Ga0.3As buried-channel metal-oxide-semiconductor field-effect transistors (MOSFETs) with Al2O3 as gate dielectric. The device combines a 3-nm Al2O3 layer grown by atomic-layer-deposition (ALD) and a 13-nm In0.52Al0.48As insulator grown by molecular-beam-epitaxy (MBE). Our long channel device with Lg=200nm exhibits excellent subthreshold characteristics, such as subthreshold-swing (S) of 68mV/decade at VDS=0.5V, indicating a very good interface quality between Al2O3 and In0.52Al0.48As. In addition, a short-channel device with Lg=60nm maintains electrostatic integrity of the device, such as subthreshold-swing (S)=90mV/decade and drain-induced-barrier-lowering (DIBL)=100mV/V at VDS=0.5V. We show well-behaved electrostatic scaling behavior that follows a modified FD-SOI MOSFET model. Our experimental and theoretical research suggest that further device optimization in the form of a self-aligned contact structure and aggressive EOT scaling would lead to high-performance III–V MOSFETs for multiple types of applications.