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Title: InP substrate evaluation by MOVPE growth of lattice matched epitaxial layers.

InP substrates form the starting point for a wide variety of semiconductor devices. The surface morphology produced during epitaxy depends critically on the starting substrate. We evaluated (1 0 0)-oriented InP wafers from three different vendors by growing thick (5 mu m) lattice-matched epilayers of InP, Gain As, and AlInAs. We assessed the surfaces with differential interference contrast microscopy and atomic force microscopy. Wafers with near singular (1 0 0) orientations produced inferior surfaces in general. Vicinal substrates with small misorientations improved the epitaxial surface for InP dramatically, reducing the density of macroscopic defects while maintaining a low RMS roughness. GaInAs and AlInAs epitaxy step-bunched forming undulations along the miscut direction. Sulfur-doped wafers were considered for singular (1 0 0) and for 0.2 degrees misorientation toward (1 1 0). We found that mound defects observed for InP and GaInAs layers on iron-doped singular wafers were absent for singular sulfur-doped wafers. These observations support the conclusion that dislocation termination at the surface and expansion of the step spiral lead to the macroscopic defects observed.
Authors:
;
Publication Date:
OSTI Identifier:
1027034
Report Number(s):
SAND2010-6178C
TRN: US201121%%244
DOE Contract Number:
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: Proposed for presentation at the 15th International Conference on Metal Organic Vapor Phase Epitaxy held May 23-28, 2010 in Lake Tahoe, NV.
Research Org:
Sandia National Laboratories
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ATOMIC FORCE MICROSCOPY; DEFECTS; DISLOCATIONS; EPITAXY; EVALUATION; INDIUM PHOSPHIDES; MICROSCOPY; MORPHOLOGY; ROUGHNESS; SEMICONDUCTOR DEVICES; SUBSTRATES; VAPOR PHASE EPITAXY