A new δ-doped In0.24Ga0.76As/GaAs pseudomorphic high electron mobility transistor (HEMT) using a graded superlattice spacer grown by molecular beam epitaxy (MBE) has been successfully fabricated and investigated. The present device structure demonstrated a more than 40% enhancement of electron mobility and 20% higher product value of electron mobility and two-dimensional electron gas (2DEG) concentration than those of the conventional HEMT with single undoped spacer under the same growth specifications. Superior device characteristics were achieved by employing the thickness-graded superlattice spacer to accommodate the lattice-mismatch-induced strain and to improve the interfacial quality. For a gate length of 1 μm, the maximum drain-to-source saturation current density and extrinsic transconductance of the present HEMT design are 165 mA mm-1 and 107 mS mm-1, respectively, at room temperature.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Electrical and Electronic Engineering