Selective area epitaxy (SAE) is an established means to control the lateral size and height of epitaxial features. An enhanced growth rate is observed to be a function of mask dimensions. In this study, the effects of reactor pressure and configuration on the SAE of GaAs were studied. Using a SiO2 mask in a dual stripe configuration, the growth rate enhancement and mesa shape were measured at reactor pressures ranging from 50 to 600 Torr. Results are obtained using a close-coupled showered (CCS) reactor design and compared to a conventional horizontal reactor. The CCS reactor demonstrates a wide range of pressure for stable operation, which has notable advantages for SAE. (C) 2003 Elsevier B.V. All rights reserved.