Control of GaAs and InGaAs Insulator-Semiconductor and Metal-Semiconductor Interfaces by Ultrathin Molecular Beam Epitaxy Si Layers

Abstract

Removal or control of Fermi level pinning is attempted using an ultrathin molecular beam epitaxy (MBE) Si interface control layer (Si ICL) for insulator-semiconductor (I-S) and metal-semiconductor (M-S) interfaces of GaAs and InGaAs. For successful removal of Fermi level pinning at the I-S interface, the Si ICL should maintain an ordered pseudomorphic structure. The optimum thickness of the Si ICL is about 10 Å. Formation of such a Si ICL alone does not remove pinning; subsequent deposition of a SiO2 film is necessary for unpinning. Pinning at the air-exposed surfaces can be removed by combining an HF surface treatment with the Si ICL technique. The Si ICL technique is promising for controlling barrier heights at M-S interfaces.