Surface morphology of metalorganic vapor phase epitaxy grown GaAs, GaInP for heterojunction bipolar transistor applications with nitrogen as the carrier gas

The MOCVD growth of GaAs, GaInP for heterojunction bipolar transistor (HBT) applications was carried out in a horizontal low pressure reactor. Nitrogen was used as the carrier gas. After growth, the samples were examined using an atomic force microscope (AFM). Monolayer steps were observed on the GaAs surface. The growth mechanism is the step flow mode according to the BCF theory. The step width varies between 25 nm and 240 nm, which is determined by the growth conditions. The step width decreases with lower growth temperature and higher growth rate. Monolayer steps were also observed on the GaInP surface.