High Electron Mobility Metal–Insulator–Semiconductor Field-Effect Transistors Fabricated on (111)-Oriented InGaAs Channels

Abstract

Metal-insulator-semiconductor field-effect transistors (MISFETs) were fabricated on the (111)A surface of In 0:53 Ga 0:47 As for the first time. Al 2 O 3 gate dielectrics were formed by atomic layer deposition on sulfur-stabilized InGaAs surfaces. The MISFET on (111)A demonstrated channel mobility higher than that on (100), achieving more than 100% improvement with respect to Si even at a high surface carrier concentration.

Electron mobility in ultra-thin InGaAs channels: Impact of surface orientation and different gate oxide materials

“…This structure is chosen to match the fabricated devices from [13], since that report contains the measured mobility data for both (1 0 0) and (1 1 1) bulk Al 2 O 3 -InGaAs-InP MOSFETs. The barrier heights are finite which results in wave-function penetration into the oxide and substrate.…”

“…In the calibration simulations, the quality of the back (InGaAs-InP) interface is kept constant (N int,B = 10 11 cm À2 , L B = 2.0 nm, D B = 0.6 nm) while the parameters of the front (Al 2 O 3 -InGaAs) interface are fitted (N int,F , L F , D F ) in order to achieve good match with the experimental data from [13]. Fig.…”

“…In the simulations, T B = 20 nm was set for the bulk device even though the InGaAs thickness was 1 lm in the fabricated devices [13]. In Fig.…”

“…One among the possible methods is using alternative surface orientations, e.g. Ishii et al [13] have shown that (1 1 1)-oriented bulk InGaAs channels offer up to 30% improved electron mobility compared to (1 0 0) device. However, experimental data is available only for bulk (1 1 1) InGaAs MOSFET and virtually nothing is known about electron mobility in UTB (1 1 1)-oriented InGaAs devices [14].…”

“…Therefore, a modeling study is necessary in order to determine the behavior of mobility in ultra-thin (1 1 1) InGaAs channels. Furthermore, the devices from [13] are fabricated with Al 2 O 3 as gate dielectric, which necessitates the assessment of the impact of other technologically relevant gate oxides on the mobility in UTB InGaAs devices. In this paper, we use physics-based modeling to study the impact of body thickness downscaling, (1 1 1) and (1 0 0) surface orientation, and different gate oxides (SiO 2 , Al 2 O 3 , and HfO 2 ), on the electron mobility in ultra-thin InGaAs layers sandwiched between a gate oxide and InP as substrate.…”