InP based double heterojunction bipolar transistorwith carbon doped GaAsSb:C base grown by LP-MOVPE

We present the growth of highly carbon doped GaAsSb on InP substrate with LP-MOVPE and nitrogen carrier gas.Carbon doped GaAsSb lattice matched on InP are of pronounced interest for high speed double heterostructure bipolar transistors (DHBTs).We observed a significant effect of the nitrogen carrier gas on the growth behaviour which results in lower distribution coefficients.A linear doping behaviour with small CBr4 flows up to p=4 x 10 19 cm-3 can be observed and first realized DHBT structures shown fT and fmax values of 100 GHz and 60GHz, respectively

Mechanism of Current Gain increase of Heterostructure Bipolar Transistors Passivated by Low-Temperature Deposited SiNx

The graded base InGaAs//InP heterostructure bipolar transistors (HBTs)were passivated by the low-temperature plasma deposited iNx .The current gain was found to increase after the passivation.The study of the Gummel plots shows that the passivation results in the reduction of both the collector current and base current,while the decrease of the base current is more significant.This causes the increase of the current gain.Nitrogen plasma treatment results in the increase of the current gain,while Silane plasma treatment results in a small reduction of the current gain.The influence of the plasmas of the two sources on the HBTs ’ performance are investigated..In- situ ellipsometer study showed that at the initial state of SiNx deposition,the SiNx deposition rate was zero,and nitrogen plasma has strong effects on the passivation of HBTs and results in the increase of the current gain. surface recombination,these cause the increase of the base current and the decrease of current gain

InP-BASED HBT with graded InGaAlAs BASE layer grown by LP-MOVPE

A compositionally graded InGaAlAs:C base layer is inserted in an InP-based HBT grown by LP-MOVPE with a novel non-gaseous source configuration. Due to the addition of 6% Al the active hole concentration in the HBT base layer, deduced from Hall measurements, is increased from 1.5 10 19 to 3.8 10 19 cm -3 . Moreover, an In-grading within the base layer results in an intrinsic electric field of about 5.4 kV/cm. A high dc current gain of β = 35 is provided at a high p-type doping level. First HBT devices exhibit a current gain cut-off frequency of fT = 117 GHz and an unilateral gain cut-off frequency of 90 GHz (not de-embedded)