Calculation of the Liquidus Isotherms and Component Activities in the Ga-As-Si and Ga-P-Si Ternary Systems

Abstract

Liquidus isotherms and thermodynamic activities have been calculated for the Ga-As-Si and Ga-P-Si ternary systems. The calculations are based on the assumption that the activities of the components in the liquid phase can be represented with sufficient accuracy by the ternary regular solution model. A least square analysis of the liquidus data for Si-doped GaAs yields the three ternary interchange energies (i.c.e.'s). These are then used to construct the liquidus isotherms for Si-doped GaAs, Ga-and As-doped Si, and the ternary eutectic valley, all of which are in excellent agreement with the experimental results over a wide temperature and composition range. The ternary Ga-As and Ga-Si i.c.e.'s are in very good accord with the i.c.e.'s derived from the binary data but a similar test for the Si-As i.c.e, shows a less satisfactory agreement. As the Ga-P-Si system has not yet been investigated, the calculations presented here are based solely on binary data and they need experimental confirmation. The implications of these results to crystal growth and the limitations of the regular solution model in the vicinity of the compound composition SiAs are also discussed.

Binary Phase Diagrams and Thermodynamic Properties of Silicon and Essential Doping Elements (Al, As, B, Bi, Ga, In, N, P, Sb and Tl)

“…Talc was used as a solid pressure-transmitting medium to generate pressure inside the test chamber [ 111 ]. The As-Si equilibrium phase diagram at a pressure of ~39.5 atm was evaluated by Olesinski and Abbaschian [ 112 ] based on the available experimental data [ 42 , 113 , 114 , 115 , 116 , 117 , 118 , 119 ] and thermodynamic descriptions [ 120 , 121 , 122 , 123 ], as shown in Figure 7 . The liquid phase boundary of the As-Si system in the Si-rich side, up to the eutectic point at around 56 at % Si, was drawn as dotted line in the work of Olesinski and Abbaschian [ 112 ] due to the large disagreement among the available data [ 113 , 115 ].…”

“… ( a ) Enthalpy of mixing of the Ga-Si liquid at 1477 °C; ― : [ 185 ]; □: [ 195 ] and [ 196 ] at 1487 ± 5 °C; - · - · - : [ 121 ]; - ·· - ·· - : [ 120 ]; -----: [ 122 ]; ▽: [ 197 ]; ···· : [ 51 ] at >1414 °C and ( b ) Activity of gallium and silicon in the Ga-Si liquid; ― : [ 185 ]; -·-·-: [ 196 ] and ------ : [ 67 ] at 1477 °C. …”

Observations on Si Contamination in GaP LPE

“…(Oxygen and all the lighter elements are not detected with the x -r a y unit.) This conclusion is reached because these precipitates are not produced if 02 is deleted from the same growth procedure, and elemental Si will not precipitate from a G a S P melt at 975~ for Si concentrations in ~he melt ~ 15% (8).…”

Liquid-Phase Epitaxy

“…There is a vast body of literature on phase equilibria modeling relevant to LPE [14,18,25,[40][41][42][43][44][45][46][47][48][49][50][51][52], mostly directed toward specific materials systems such as Si, Ge, SiGe, SiC, III-V and II-V binary compounds and their ternary, quaternary, and quinary alloys. The equilibrium vapor-phase composition can impact stoichiometry, defects, and loss of melt components due to evaporation, but is ususally of secondary importance in LPE modeling.…”