Doping studies using thermal beams in chemical-beam epitaxy

The use of chemical-beam expitaxy instead of chemical vapor deposition allows the incorporation of thermal atomic beams for doping. Dopant profile measurements by a differential capacitance-voltage technique and secondary ion mass spectroscopy technique show that there is no surface segregation with Si dopants in InP at all growth temperatures (<600 °C). On the other hand, Sn and to a lesser extent Be show surface segregation which can be reduced by growing the InP at a lower temperature (<550 °C). From this study, it is seen that Si should be preferred as the n-type dopant in producing InP/InGaAs high electron mobility transistors.