Study of InGaAs-Based Modulation Doped Field Effect Transistor Structures Using Variable-Angle Spectroscopic Ellipsometry

Authors

S. A. Alterovitz, National Aeronautics and Space Administration, Lewis Research Center, Cleveland, Ohio
R. M. Sieg, Cleveland State University, Department of Electrical Engineering, Cleveland, Ohio
H. D. Yao, University of Nebraska - Lincoln
Paul G. Snyder, University of Nebraska-LincolnFollow
John A. Woollam, University of Nebraska-LincolnFollow
J. Pamulapati, University of Michigan, Department of Electrical Engineering and Computer Science, Ann Arbor, MI
P. K. Bhattacharya, University of Michigan, Department of Electrical Engineering and Computer Science, Ann Arbor, MI
P. A. P. A. Sekula-Moise, Spire Corporation, Bedford, MA

Date of this Version

1991

Comments

Published in Thin Solid Films, 206 (1991) 288-293. Copyright © 1991 Elsevier Sequoia, Lausanne. Used by permission.

Abstract

Variable-angle spectroscopic ellipsometry was used to estimate the thicknesses of all layers within the optical penetration depth of InCaAs-based modulation doped field effect transistor structures. Strained and unstrained InGaAs channels were made by molecular beam epitaxy (MBE) on InP substrates and by metal-organic chemical vapor deposition on GaAs substrates. In most cases. ellipsometrically determined thicknesses were within 10% of the growth-calibration results. The MBE-made InCaAs strained layers showed large strain effects, indicating a probable shift in the critical points of their dielectric function toward the InP lattice-matched concentration.