InGaAs/InP double heterojunction bipolar transistors with fmax=532GHz

An InGaAs/InP DHBT with InGaAsP composite collector is designed and fabricated using triple mesa structure and planarization technology. All processes are on 3-inch wafers. The DHBT with emitter area of 0.5×5μm
²
exhibits a current cutoff frequency f
_t
=350GHz and a maximum oscillation frequency f
_max
=532GHz which is to our knowledge the highest BV
_CEO
ever reported for InGaAs/InP DHBTs in China. The breakdown voltage is 4.8V. The high speed InGaAs/InP DHBTs with high breakdown voltage are promising for voltage controlled oscillator (VCO) and mixer applications at THz span.