Buried-channel (BC) high-κ/metal gate pMOSFETs were fabricated on Ge1-xCx layers for the first time. Ge1-x Cx was grown directly on Si (100) by ultrahigh-vacuum chemical vapor deposition using methylgermane (CH3GeH3) and germane (GeH4) precursors at 450 °C and 5 mtorr. High-quality films were achieved with a very low root-mean-square roughness of 3 Å measured by atomic force microscopy. The carbon (C) content in the Ge1-xCx layer was approximately 1 at.% as measured by secondary ion mass spectrometry. Ge1-x Cx BC pMOSFETs with an effective oxide thickness of 1.9 nm and a gate length of 10 μm exhibited high saturation drain current of 10.8 μA/μm for a gate voltage overdrive of -1.0 V. Compared to Si control devices, the BC pMOSFETs showed 2× enhancement in the saturation drain current and 1.6× enhancement in the transconductance. The Ion/Ioff ratio was greater than 5 × 104. The improved drain current represented an effective hole mobility enhancement of 1.5× over the universal mobility curve for Si.
- Germanium (Ge)
- Germanium/carbon alloy (GeC)
- Methylgermane (CHGeH
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering