AlGaSb Buffer Layers for Sb-Based Transistors
NAVAL RESEARCH LAB WASHINGTON DC ELECTRONICS SCIENCE AND TECHNOLOGY DIV
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InAs quantum wells can serve as the channel for high-electron-mobility transistors. Structures are typically grown on semi-insulating GaAs substrates with 1.5 lm to 3.0 lm buffer layers of AlSb and AlGaSb accommodating the lattice mismatch. We demonstrate that high electron mobility in the InAs 20,000 cm2V s at 300 K and smooth surfaces can be achieved with Al0.8Ga0.2Sb buffer layers as thin as 600 nm, grown at rates of 1.5 monolayerss to 2.0 monolayerss. The use of thinner buffer layers reduces molecular beam epitaxial growth time and source consumption. The buffer layers also exhibit higher resistivity, which should reduce excess gate leakage current and improve device isolation.
- Electrical and Electronic Equipment