AlGaAs/GaAs heterojunction bipolar transistors (HBTs) are used for digital and analog microwave applications with frequencies as high as Ku band. HBTs can provide faster switching speeds than silicon bipolar transistors mainly because of reduced base resistance and collector-to-substrate capacitance. HBT processing requires less demanding lithography than GaAs FETs, therefore, HBTs can cost les...

A method is described for measuring the bandgap narrowing in the base of a Si homojunction or SiISiGe heterojunction bipolar transistor from the temperature dependence of the collector current. The model includes the temperature dependence of the intrinsic carrier concentration, the bandgap, the minority carrier mobility, and freeze-out of dopant in the base. The analysis method is applied to t...

A new insight on the behavior of metal contact-insulating interfaces in SiGe heterojunction bipolar transistor is given by high-performance aberration-corrected scanning transmission electron microscopy (STEM) analysis tools equipped with sub-nanometric probe size. It is demonstrated that the presence of initial defects introduced during technological processes play a major role in the accelera...

The temperature-dependent direct current dc characteristics and radio frequency performance of an InGaP/GaAs heterojunction bipolar transistor with the composite passivations on base surface are studied and demonstrated. For comparison, the characteristics of other samples with different treatments on the base surfaces are also included in this work. The device with composite passivations, i.e....

The suitability of high-resolution X-ray diffraction (HRXRD) as an in-line measurement tool for the characterization of heterojunction bipolar transistor SiGe base layers and Si cap layers was investigated. We showed that despite of polycrystalline Si on the mask material of patterned wafers, HRXRD measurements performed on an array of small windows yield results which are comparable to those t...

This paper explains the development of physical model Heterojunction Bipolar Transistor (HBT) and characterizes its performance as an optoelectronic mixer (OEM). HBT has been identified as a suitable device to be implemented in optoelectronic mixers by simultaneously photodetecting an intensity modulated laser beam at 1550nm and frequency translating the detected signal to a higher or lower fre...

We have performed transport measurements on a gallium phosphide antimonide (GaPSb) film grown on GaAs. At low temperatures (T), transport is governed by three-dimensional Mott variable range hopping (VRH) due to strong localization. Therefore, electron-electron interactions are not significant in GaPSb. With increasing T, the coexistence of VRH conduction and the activated behavior with a gap o...

This letter describes the use of a power-optimized cascode configuration for obtaining maximum output power at millimeter-wave (mm-wave) frequencies for a two-way combined power amplifier (PA). The PA has been fabricated in a high-speed InP double heterojunction bipolar transistor technology and has a total active emitter area of 68.4 lm2. The experimental results demonstrate a small signal gai...

Large parasitic series resistances of heterojunction bipolar transistor (HBT) are shown to cause a sharp kink in the base current (IB) of the Gummel plot at elevated temperatures under high collector currents (IC) and low base-collector (b-c) applied bias (VBC). This effect was analyzed and attributed to the temperature dependence of low-field and high field mobilities of undepleted and deplete...