Extraction of the average collector velocity in high-speed "Type-II" InP-GaAsSb-InP DHBTs

In "type-II" NpN InP-GaAsSb-InP double heterostructure bipolar transistors DHBTs), the p/sup +/ GaAsSb base conduction band edge lies /spl Delta/E/sub C/ above the InP collector conduction band: a small ballistic injection energy /spl Delta/E/sub C/ is thus imparted to electrons as they are launched into the collector. The resulting high initial velocity should in principle reduce the collector signal delay time in comparison to the case where thermal electrons are accelerated by the collector electric field alone. We extract the bias dependence of the average collector electron velocity in high-speed InP-GaAs/sub 0.62/Sb/sub 0.38/-InP DHBTs, and find a maximum average velocity reaching 4/spl times/10/sup 7/ cm/s across a 2000 /spl Aring/ InP collector. This finding provides evidence of the performance advantage afforded by abrupt type-II base/collector (B/C) junctions for collector transport when compared to other B/C junctions.

[1]  John C. Woolley,et al.  Electron effective mass values in GaAsxSb1−x alloys , 1969 .

[2]  S. Blayac,et al.  Measurement of base and collector transit times in thin-base InGaAs/InP HBT , 2003, IEEE Electron Device Letters.

[3]  M. Peter,et al.  BAND GAPS AND BAND OFFSETS IN STRAINED GAAS1-YSBY ON INP GROWN BY METALORGANIC CHEMICAL VAPOR DEPOSITION , 1999 .

[4]  S. P. Watkins,et al.  Type-II Base-Collector Performance Advantages and Limitations in High-Speed NpN Double Heterojunction Bipolar Transistors (DHBTs) , 2003 .

[5]  Mark S. Lundstrom,et al.  Technique for measurement of the minority carrier mobility with a bipolar junction transistor , 1997 .

[6]  K. Kavanagh,et al.  Anisotropic resistivity correlated with atomic ordering in p-type GaAsSb , 2001 .

[7]  M. Lundstrom.  Fundamentals of carrier transport , 1990 .

[8]  S. P. Watkins,et al.  300 GHz InP/GaAsSb/InP Double HBTs with High Current Capability and V , 2001 .

[9]  S. Laux,et al.  Collector signal delay in the presence of velocity overshoot , 1990, IEEE Electron Device Letters.

[10]  T. Ishibashi.  Influence of electron velocity overshoot on collector transit times of HBTs , 1990 .

[11]  David C. Look,et al.  Electrical Characterization of GaAs Materials and Devices , 1989 .

[12]  Jeremiah R. Lowney,et al.  Majority and minority electron and hole mobilities in heavily doped GaAs , 1991 .

[13]  Mark S. Lundstrom.  Fundamentals of Carrier Transport, 2nd edn , 2002 .

[14]  C. Bolognesi,et al.  300 GHz InP/GaAsSb/InP double HBTs with high current capability and BV/sub CEO/>6 V , 2001, IEEE Electron Device Letters.

[15]  G. Bahir,et al.  Measurement of the minority carrier mobility in the base of heterojunction bipolar transistors using a magnetotransport method , 1995 .