Abstract
We have studied the uniformity of both the structure and of the device characteristics of PM-HEMTs on (001) GaAs substrates. The structure uniformity was studied by photoreflectance modulation spectroscopy (PR) at room temperature and photoluminescence spectroscopy (PL) at low temperature. PR was chosen for its main advantages of high sensitivity in room temperature, higher than that of high temperature photoluminescence and non-destructiveness. We have studied the main transitions of the transistor structures using the 2DEG approximation. PR and PL results yield uniformity with relative standard deviation (r.s.d.) lower than 1%. After PR, transistors were fabricated on the wafers and tested for DC and RF characteristics and the results were correlated with the PR data. The comparison between PR and PL has resulted in a strong indication that PR can be the technique of choice for the complete characterization of structure uniformity of 3 inch pseudomorphic heterostructures, since it is non-destructive, relatively simple and can be performed at room temperature. © 1998 Elsevier Science B.V. All rights reserved.