Aδ-doped In0.24Ga0.76As/GaAs pseudomorphic high electron mobility transistor using a graded superlattice spacer
✍ Scribed by Ching-Sung Lee; Wei-Chou Hsu; Sheng San Li; Pin Ho
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 174 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0749-6036
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✦ Synopsis
A new δ-doped In 0.24 Ga 0.76 As/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.