Schottky barrier height modification on high-purity LPE GaAs following a sulphur-based etch

K. S. A. Butcher*, D. Alexiev, V. W. L. Chin, T. L. Tansley, R. J. Egan, M. Keane

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Nuclear radiation detectors constructed from GaAs Schottky barrier structures require control of barrier height if high resolution is to be reproducibly obtained. The authors have therefore studied the variation of device barrier height after treatment with common etching solutions. The heights of Au and Al Schottky barriers on respective samples of n- and p-type liquid-phase epitaxial GaAs were found from reverse bias I-V measurements subsequent to etching with aqua regia and 3H2SO4:H 2O2:H2O (3:1:1). An increase in barrier height observed after the 3:1:1 etch was found to be a consequence of sulphur contamination. This result is consistent with those reported for deliberate sulphur passivation of GaAs. Low diode ideality factors, from 1.007 to 1.064, were measured for layers with carrier concentrations in the range 4*1014 cm-3 to 2.5*1016 cm -3. A comparison was made between samples etched in the 3:1:1 solution at 5 degrees C and at 100 degrees C. C-V measurements gave anomalously large barrier heights for those samples etched at 5 degrees C, indicating the formation of a significant interfacial layer prior to Schottky barrier metallization, while X-ray photoelectron spectroscopy measurements confirmed the presence of a large oxide layer. No such anomalies were observed for the samples etched in 3:1:1 at 100 degrees C.

Original languageEnglish
Article number041
Pages (from-to)1451-1458
Number of pages8
JournalSemiconductor Science and Technology
Issue number7
Publication statusPublished - 1993


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