A new heterojunction bipolar transistor (HBT) structure with buried SiO2 wires is proposed. SiO2 wires were buried in the InP layer by metalorganic vapor-phase epitaxy (MOVPE). The insertion of SiO2 wires under the base electrodes reduces collector capacitance because of a small dielectric constant. Two SiO2 wires of 200 nm width and 60 nm height on the InP substrate were buried in an InP DHBT structure with a flat heterointerface when the buried growth temperature was 580 degrees C and the direction of the wire was < 010 >. (c) 2006 Elsevier B.V. All rights reserved.