Studies on MOVPE growth of GaP epitaxial layer on Si(001) substrate and effects of annealing

Growth of gallium phosphide layer on silicon substrate has been carried out using metal-organic vapor phase epitaxy. Epitaxial layers were grown at 845 degrees C with a V/III ratio of 100 and a growth rate of 1.7 A slat a reactor pressure of 30 mbar. The nominal thickness of the gallium phosphide epitaxial layer is similar to 600 nm as measured by cross-sectional scanning electron microscopy. Growth of gallium phosphide epilayer is confirmed by Raman spectra studies. High-resolution X-ray diffraction studies show that the epilayer is of single crystalline nature and structurally coherent with silicon substrate. It is also inferred from these measurements that the in- and out of plane strain arising from small mismatch confirms a relaxed epilayer. As-grown epilayer shows p-type behavior with a hole carrier density of similar to 1.2 x 10(18)cm(-3) and hole mobility 114 cm(-2)V s(-1) at room temperature. Annealing at 550 degrees C for 10 min shows significant improvements in crystalline quality of the epilayer. The annealed layer shows a reduced hole density (similar to 6.7 x 10(17)cm(-3)) and increased hole mobility (155 cm(-2) v s(-1)). (c) 2006 Elsevier B.V. All rights reserved.