Adsorption and desorption of the surfactant Sb on GaInP grown by organometallic vapor phase epitaxy

It has been determined that ordering has a profound effect on the bandgap energy of many compound semiconductor alloys. Therefore, ordering must be controlled for devices such as solar cells, light emitting diodes and diode lasers. Since ordering depends on the surface properties during organometallic vapor phase epitaxy (OMVPE), the ability to control the surface has been shown to be important for controlling ordering and for producing heterostructures and quantum wells. However, perhaps equally as important as the affect of ordering on the bandgap is the fundamental information that it can provide about the surface during growth. This paper reports on the use of time dependent surface photoabsorption (SPA) measurements to determine the rate of change in the P dimer concentration when TESb is added to and removed from the reactor. In particular, the time constants for the transients are presented and compared with the Langmuir model for adsorption and desorption of the surfactant. Transients in the Sb surface concentration were also indirectly determined from secondary-ion mass spectroscopy (SIMS) measurements on a GaInP heterostructure where TESb was added during growth of one of the layers.