Photoreflectance Study of the Chemically Modified (100) GaAs Surface

Published

May 1, 1994

Author(s)

John A. Dagata, O Glembocki, J Tuchman, K Ko, S Pang

Abstract

Photoreflectance (PR) spectroscopy has been used to study the Fermi-level pinning position of chemically modified (100) GaAs surfaces. It is shown that there are two pinning positions for the unmodified (100) GaAs surface. For n-GaAs, the Fermi level pins near midgap, while for p-GaAs the Fermi level pins near the valence band. We used an Ar/Cl(2) plasma generated by an electron-cyclotron resonance (ECR) source and P2S5 chemical passivation to change the stoichiometry of the surface. We show that ECR etching makes the surface oxide As rich and that the Fermi-level position for this circumstance is near midgap. The P(2)S(5) passivation produces a thin Ga rich oxide which is observed to pin the Fermi-level near the valence band. These results allow us to relate the Fermi-level pinning position to the stoichiometry of the GaAs/oxide interface.

Proceedings Title

Proceedings of SPIE

Volume

2141

Conference Dates

January 26, 1994

Conference Location

Los Angeles, CA, USA

Conference Title

Spectroscopic Characterization Techniques for Semiconductor Technology V, Orest J. Glembocki, Editor May 1994, Semiconductor Device Characterization I

Pub Type

Conferences

Citation

Dagata, J. , Glembocki, O. , Tuchman, J. , Ko, K. and Pang, S. (1994), Photoreflectance Study of the Chemically Modified (100) GaAs Surface, Proceedings of SPIE, Los Angeles, CA, USA (Accessed April 26, 2025)