Comparison of different grading approaches in metamorphic buffers grown on a GaAs substrate

• Published in: Journal of crystal growth 2014-01, Vol.386, p.183-189
• Main Authors: Saha, Sudip, Cassidy, Daniel T., Thompson, D.A.
• Format: Article
• Language: English
• Subjects: Buffers; Cations; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Crystal growth; Equations of state, phase equilibria, and phase transitions; Evaluation; Exact sciences and technology; Gallium arsenide; Grading; Materials science; Metamorphic; Metamorphic buffers; Methods of crystal growth; physics of crystal growth; Phase separation; Physics; Pseudo-substrate; Quaternary buffers; Solubility, segregation, and mixing; phase separation; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2013.10.015

Linear and logarithmic step thickness grading for ternary (In0.194Ga0.806As), cation graded, and quaternary (In0.485Ga0.515As0.4P0.6), anion graded metamorphic buffers have been investigated. The group III ratio was kept fixed during the quaternary growths. Comparison between the samples showed that using a higher grading slope at the beginning of the growth and decreasing the grading slope as the growth progresses leads to improvement in the quality of the metamorphic buffers. However, owing to the existence of phase separation, the quaternary buffers showed poorer quality of the final metamorphic pseudo-substrate layers than for the ternary graded metamorphic buffers. •Proposed a better way to grow the pseudo-substrates.•Investigated the potentiality of InGaAsP metamorphic buffer.•Investigated the effects of grading slope.•For the first time degree of polarization was used to characterize the metamorphic pseudo-substrate.