Current gain increase by SiNx passivation in InGaAs/InP double heterostructure bipolar transistors

Passivation of InGaAs/InP double heterostructure bipolar transistors (DHBTs) with room temperature SiNx deposition was investigated. Due to reduction of surface damages during SiNx deposition, current gain improvement was observed at low bias voltage region. According to our analysis, a drastic decrease of surface recombination related current component at base-emitter junction occurred after passivation, which is crucial for improving the device reliability.