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Title:Carbon doping of compound semiconductor epitaxial layers grown by metalorganic chemical vapor deposition using carbon tetrachloride
Author(s):Cunningham, Brian Thomas
Doctoral Committee Chair(s):Stillman, Gregory E.
Department / Program:Electrical and Computer Engineering
Discipline:Electrical and Computer Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Chemistry, Organic
Engineering, Electronics and Electrical
Physics, Condensed Matter
Abstract:A dilute mixture of CCl$\sb4$ in high purity H$\sb2$ has been used as a carbon dopant source for $\rm Al\sb{x}Ga\sb{1-x}As$ grown by low pressure metalorganic chemical vapor deposition (MOCVD). To understand the mechanism for carbon incorporation from CCl$\sb4$ doping and to provide experimental parameters for the growth of carbon doped device structures, the effects of various crystal growth parameters on CCl$\sb4$ doping have been studied, including growth temperature, growth rate, V/III ratio, Al composition, and CCl$\sb4$ flow rate. Although CCl$\sb4$ is an effective p-type dopant for MOCVD $\rm Al\sb{x}Ga\sb{1-x}As$, injection of CCl$\sb4$ into the reactor during growth of InP resulted in no change in the carrier concentration or carbon concentration.
Abrupt, heavy carbon doping spikes in GaAs have been obtained using CCl$\sb4$ without a dopant memory effect. By annealing samples with carbon doping spikes grown within undoped, n-type, and p-type GaAs, the carbon diffusion coefficient in GaAs at 825$\sp\circ$C has been estimated and has been found to depend strongly on the GaAs background doping. Heavily carbon doped $\rm Al\sb{x}Ga\sb{1-x}As$/GaAs superlattices have been found to be more stable against impurity induced layer disordering (IILD) than Mg or Zn doped superlattices, indicating that the low carbon diffusion coefficient limits the IILD process.
Carbon doping has been used in the base region on an Npn AlGaAs/GaAs heterojunction bipolar transistor (HBT). Transistors with 3 x 10 $\mu$m self-aligned emitter fingers have been fabricated which exhibit a current gain cutoff frequency of f$\sb{\rm t}$ = 26 GHz.
Issue Date:1990
Rights Information:Copyright 1990 Cunningham, Brian Thomas
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9026165
OCLC Identifier:(UMI)AAI9026165

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