GROWTH OF UNDOPED INDIUM-PHOSPHIDE BY OMVPE IN AN INVERTED-VERTICAL REACTOR USING TRIMETHYLINDIUM AND TERTIARYBUTYLPHOSPHINE AND PHOSPHINE

The as-grown morphologies and background carrier concentrations of und oped InP epilayers grown at 650-degrees-C were determined as a functio n of phosphorus source [tertiarybutylphosphine (TBP) or phosphine (PH3 )] and V:III ratio in an inverted-vertical (IV) metallorganic chemical vapor deposition (MOCVD) reactor. Specular surface morphology was obt ained over the entire growth surf ace (16.6 cm2) at a minimum PH3 to t rimethylindium (TMIn) ratio of 1 0, and at a minimum TBP to TMIn ratio of 33. Below these V:III ratios, the area of the InP epilayer surface s exhibiting specular morphology decreased as the V:III ratio was redu ced; however, the layer thicknesses remained uniform. All undoped InP epilayers were n-type. The carrier concentration (N(D)-N(A)) obtained with PH3 in the specular area of the InP epilayers was on the order of 1.5 x 10(14) cm-3 at V:III ratios up to ca. 20; at a V:III ratio of 4 0, N(D)-N(A) decreased to 10(12) cm-3. The carrier concentration obtai ned with TBP in the specular area of the InP epilayers was about 3.6 x 10(15) cm-3 at V:III ratios up to 33. The relation of V:III ratio to morphology and the distribution of visible phosphorus deposition on th e reactor tube walls during growth indicated that the decomposition ch aracteristics of PH, and TBP are considerably different in the inverte d vertical reactor than in other system configurations. The decomposit ion characteristics observed here are empirically correlated with deco mposition mechanism unique to the IV geometry.