High-speed InGaP/InGaAsN/GaAs NpN double heterojunction bipolar transistors with low turn-on voltage

Comparison of heterostructure-emitter bipolar transistors (HEBTs) with InGaAs/GaAs superlattice and quantum-well base structures

“…However, the conventional HBTs suffered from a large collector-emitter offset voltage (DV CE ) resulting from a considerable base-emitter (B-E) turn-on voltage, which severely limits the minimum operated voltage and causes high power consumption in circuit applications [3,4]. It is well known that two usual approaches, i.e., the reduction of potential spike at B-E junction [5][6][7] and the employment of a small energy-gap material as base layer [8][9][10], have been used for the reduction of the turn-on voltage.…”

“…In addition, the use of the In x Ga 1Àx As 1Ày N y as base layer have been demonstrated to further reduce the energy-gap of base and it effectively improved the problem associated with excess strain [10]. Unfortunately, the blocking effect of collector current at base-collector heterojunction could induce a large knee voltage and reduce the collector current.…”

Current transport mechanism in InGaP∕GaAsSb∕GaAs double-heterojunction bipolar transistors

“…Recently, several groups have demonstrated the potential of using narrow energy bandgap InGaAsN material in the base layer to reduce the turn-on voltage. [3][4][5][6] However, InGaAsN material typically displays degraded minority carrier properties compared with GaAs, leading to the reduction of dc current gain and high frequency performance. Although these unfavorable characteristics can be suppressed by the insertion of graded layers between the base and collector junction, 4 this complicates the transistor design and fabrication.…”

Thermal stability of current gain in InGaP∕GaAsSb∕GaAs double-heterojunction bipolar transistors

“…[5][6][7][8] However, InGaAsN material typically displays degraded minority carrier properties compared with GaAs, 5,6 leading to the reduction of dc current gain and high frequency performance. The first is InGaAsN, which has been used as the base layer by several groups.…”