Date of Award

12-1999

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Department of Engineering Physics

First Advisor

Yung K. Yeo, PhD

Abstract

Deep level transient spectroscopy (DLTS), Hall effect, and cathodolummescence (CL) measurements are used to characterize the intrinsic and ion-implantation induced defects in high-temperature (475 and 500 °C) ion-implanted epitaxial n-type 6H- and 4H-SiC, ion-implanted with Cr, Mg, Ar, N, and P atoms. Comparison of room-temperature and high-temperature ion-implanted 6H-SiC:Mg and :Cr indicate the significance of high-temperature ion implantation on the activation of the ion-implanted atoms and damage-recovery of the crystalline lattice. The effects of high-temperature annealing on both damage-recovery and implanted ion activation are detected and analyzed, from 1200 to 1800 °C. Trap parameters of both damage-related and species-related defects are determined by curve-fitting of DLTS rate window plots, including the identification of a 615 meV silicon-vacancy-substitutional-nitrogen defect. Double-correlated DLTS measurements indicate a one-dimensional distribution of various defects along the implantation axis and slight surface diffusion of ion-implanted magnesium during high-temperature annealing. Current-voltage-temperature measurements of 6H-SiC:Mg :Cr indicate the effect of annealing temperature and ion species on the concentration of near midgap defects. Optimum anneal temperatures are determined for activation of ion-implanted nitrogen and phosphorus. CL measurements indicate the formation of deep radiative centers in 500 °C ion-implanted 4H-SiC:P and :N. CL measurements also indicate the presence of a 130 meV higher energy level conduction band minimum.

AFIT Designator

AFIT-DS-ENP-99-04

DTIC Accession Number

ADA371042

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