We studied the selective growth behaviors of InP through narrow openings (<2 mum) by metal-organic chemical vapor deposition. The lateral overgrowth was observed to be significantly affected by both the opening width and orientation. It was found that the lateral overgrowth length reached the maximum at 60degrees off [011] direction. The lateral overgrowth also showed a 'diffraction-like' behavior, with the overgrowth length increasing with decreasing opening width. Based on these results, a novel InP/InGaAs heterojunction bipolar transistor (HBT) structure with extrinsic base laterally overgrown on SiO2 is proposed. The device behaviors of the laterally regrown-base HBT prototypes are demonstrated. (C) 2003 Elsevier B.V. All rights reserved.