Growth and characterization of Fe-doped semi-insulating InP prepared by low-pressure organometallic vapor phase epitaxy with tertiarybutylphosphine

Abstract

Fe-doped semi-insulating InP epitaxial layers were grown by low-pressure organometallic vapor phase epitaxy with tertiarybutylphosphine (TBP), triethylindium (TEI) and iron pentacarbonyl [Fe(CO)5] as the reactant gases. The growth was performed by varying the growth rate, growth pressure and V/III ratio. The epitaxial layers were characterized by optical microscopy, secondary ion mass spectrometry, double crystal x-ray diffraction and current-voltage measurements. Semi-insulating InP epitaxial layers with specular surface morphology and low defect density were obtained at TBP partial pressure higher than 0.38 torr. A premature reaction between TEI and TBP was observed which presumably formed TEI:TBP adducts and/or polymers. As a result, the growth rate of Fe-doped semi-insulating InP layers grown at low pressure with TBP in our reactor decreased by 35% as the V/III ratio was increased from 15 to 46. Electrical measurements on these layers showed that the resistivity varied from 1.7×107 to 4×108 Ω cm as the V/III ratio was increased from 15 to 46. The resistivity of TBP-grown materials is comparable to that of PH3-grown materials over a measurement temperature range of 25–110 °C. Selective growth and surface planarization of Fe-doped InP grown with TBP and trimethylindium on patterned etched mesas were achieved.