SILICON INCORPORATION IN INP DURING LP-MOCVD USING DISILANE

Silicon doped epitaxial layers of InP have been prepared by low pressure metalorganic chemical vapour deposition, using disilane as the source of silicon. Trimethylindium and phosphine were used as the source reactants for the growth. The doping characteristics for the epitaxial growth were investigated at substrate temperatures in the range 525-750° C and for doping levels in the range 4 × 1016-2 × 1019 cm-3. The results indicated that the Si doping level is proportional to the disilane flow rate. The Si incorporation rate increases with temperature, but becomes temperature-independent for T > 620° C. Comparison between Si concentrations determined by Secondary Ion Mass Spectroscopy, donor levels determined by Hall effect measurements, and optical measurements at 7 K indicates that approximately 50% of the Si in the InP is in the form of electrically inactive species. Uniform doping over 5 cm wafer dimensions has been obtained for growth at T = 625° C. © 1990 AIME.