An innovative planarization technology for ultra high frequency InP/InGaAs heterojunction bipolar transistor (HBT) manufacturing

An innovative planarization technology is successfully demonstrated through parallel reactive etching between PECVD deposited silicon nitride and spin coated BCB. By adjusting the gas ratio of SF 6 to O 2 appropriately, equal etch rates between BCB and SiN can be reached, which results in parallel etching between two materials. With help of planarization technology, a scaled down sub-micron InP/InGaAs HBT is fabricated, and superior RF performance is presented.