Heterojunction bipolar transistor and method of manufacturing
A heterojunction bipolar transistor structure grown with organometallic vapor phase epitaxy (OVMPE) which uses zinc as the base dopant. The HBT structure has eight layers grown on a substrate, including n-type doped first, second, third, fifth, sixth, seventh, and eighth layers and a p-type zinc doped fourth layer. The first layer is a thicker, moderately doped n-type layer compared to the thinner, higher doped n-type second layer. The seventh layer is a thicker, moderately doped n-type layer compared to the thinner, higher doped n-type eighth layer. In addition, some or perhaps all of the layers have a high V/III ratio of 10-100 used to increase the gallium vacancies and reduce the diffusion of zinc from the base layer. Further, annealing of the structure is performed during growth to minimize gallium interstitials and to inhibit the diffusion of zinc.