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Semiconductor Two-Dimensional Hole Gas Heterostructures

IP.com Disclosure Number: IPCOM000062158D
Original Publication Date: 1986-Oct-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 65K

Publishing Venue

IBM

Related People

Esaki, L: AUTHOR [+4]

Abstract

The formation of high-mobility two-dimensional (2D) electron gases at the interface of GaAs-GaAlAs heterojunctions constitutes the foundation of High Electron Mobility Transistors (HEMT). Another heterostructure is the High Hole Mobility Transistor (HHOMT) that is based on a two- dimensional hole gas and has the possibility of accomplishing complementary logic. So far, the 2D electron gas has been achieved by doping with Si a GaAlAs layer grown epitaxially on undoped GaAs. Similarly, the 2D hole gas has been formed by using Be instead, as a dopant. Silicon is in principle an amphoteric impurity for GaAs, but under normal growth conditions on (100) surfaces it behaves as a donor.

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Semiconductor Two-Dimensional Hole Gas Heterostructures

The formation of high-mobility two-dimensional (2D) electron gases at the interface of GaAs-GaAlAs heterojunctions constitutes the foundation of High Electron Mobility Transistors (HEMT). Another heterostructure is the High Hole Mobility Transistor (HHOMT) that is based on a two- dimensional hole gas and has the possibility of accomplishing complementary logic. So far, the 2D electron gas has been achieved by doping with Si a GaAlAs layer grown epitaxially on undoped GaAs. Similarly, the 2D hole gas has been formed by using Be instead, as a dopant. Silicon is in principle an amphoteric impurity for GaAs, but under normal growth conditions on (100) surfaces it behaves as a donor. On the other hand, the fact that the (111) face contains only either Ga atoms (A face) or As atoms (B face) would make it possible to grow either p or n-type material, through growing an epitaxial layer on a (111) GaAs substrate. The amphoteric behavior employed in structures is achieved by growing GaAs-GaAlAs heterojunctions on GaAs substrates of various orientations, away from the (100) towards the (111) direction. Si- doped heterojunctions, grown on (311) substrates, give rise to either a 2D electron or hole gas, depending on the face (B or A) on which the heterolayers are grown. For orientations closer to the (100) direction than (311), e.g., (511), the 2D gas doped with Si is electron-like. The concept of amphotericity of Si, and the way of achieving it through the growth on either A or B faces of (111) substrates, or directions close to it, like the (311) demonstrated here, is not restricted to GaAs and GaAlAs, and could be applied to any of the other III-V compounds, when doped with a group IV element. Heteros...