In-situ strain measurement during epitaxy of InP based materials

• Published in: International Conference onIndium Phosphide and Related Materials, 2003 pp. 40 - 43
• Main Authors: Hoffman, R.W., Belousov, M., Volf, B., Murphy, M., Cruel, J., Lee, D., Gurary, A., Armour, E.A.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 2003
• Subjects: Capacitive sensors; Data mining; Epitaxial growth; Hall effect; Indium phosphide; Inductors; Instruments; Optical materials; Rotation measurement; Strain measurement
• ISBN: 0780377044; 9780780377042
• DOI: 10.1109/ICIPRM.2003.1205307

We have developed an instrument to measure wafer curvature during epitaxial growth in rotating disk reactors. This instrument uses a high speed, position sensitive, laser reflectometer to accurately measure the substrate's radius of curvature. The instrument has been used to measure ternary compound lattice-mismatch during growth. Agreement within 60 ppm was found between strains extracted from in-situ curvature measurements and the ex-situ measured strain determined by high-resolution x-ray diffraction. Discrepancy between extracted strains for two samples was explained by the onset of pseudomorphic strain relaxation and confirmed through Hall mobility data. A correlation between Hall mobility and strain of nearly lattice-matched InGaAs on InP demonstrated the importance of in-situ strain control at growth temperature. A maximum mobility was obtained with an at growth temperature strain of 375 ppm (compressive) relative to the InP substrate and not at perfect lattice-matching conditions.