Abstract: A method of fabricating a heterojunction bipolar transistor and the transistor by providing a substrate of a group III-V semiconductor material, doping a first selected region at a surface of the substrate a predetermined first conductivity type, concurrently or separately incorporating a group III element into a portion of the first selected region, doping the portion of the first selected region to a second conductivity type with a laser beam to cause melting and subsequent recrystallization of said substrate and forming contacts to the portion of the first selected region and to the first selected region. The portion of the first selected region extends farther into the substrate than the remainder of the first selected region. A complementary transistor can be concurrently fabricated using the same steps except that p-implants replace the n-implants and n-doped InGaAs instead of p-doped InGaAs forms the base layer.