Under continuous-wave operation and class-ABīiasing conditions, 24.2-dBm (263-mW) RF output power with concurrent The device exhibits collector breakdown voltage BVĬBO of more than 24 V and a maximum oscillation frequency f Transistor (HBT) with record output power and power gain at X-band (8.4 In addition, according to the van't Hoff equation, the initial values of heat adsorption for Pd/semiconductor and Pd/oxide interface are calculated as 7.29 and 49.6 KJ/mole, respectively.Ī double mesa-type Si/SiGe/Si (n-p-n) heterojunction bipolar In addition, under the presence of oxide layer in the studied MOS device, a larger change of barrier height and higher hydrogen response are observed. Particularly, at an extremely low hydrogen concentration of 15 ppm H2/air, both steady-state and transient responses at room temperature can be detected. The studied devices can be operated under very wide hydrogen concentration regimes with remarkable hydrogen-sensing properties. The effects of hydrogen adsorption on device performances such as the current-voltage characteristics, sensitivity, barrier height variation, heat of adsorption, and transient response are investigated. The hydrogen response characteristics and sensing properties or catalytic Pd/Al0.3Ga0.7As metal-oxide-semiconductor (MOS) and metal-semiconductor (MS) Schottky diodes are systematically studied. The analysis are quantitatively verified with simulation and measurement results from SiGe HBTs of representative Ge and base doping profiles. Employing a higher base doping concentration than the emitter with a box-type Ge profile considerably reduces the base resistance and thus favors the CB configuration for power amplification in this frequency range. For these devices, the CE configuration exhibits higher MSG than the CB configuration. Employing a typical doping profile of Si bipolar junction transistors with a trapezoidal Ge profile in SiGe HBTs usually results in a larger base resistance than the emitter resistance. These analyses have explicit implications on the operation configurations of SiGe heterojunction bipolar transistors (HBTs). In the intermediate frequency range, the base resistance value, mainly affected by the base doping concentration, determines which configuration offers higher maximum stable power gain (MSG).
The analysis reveals that the CB configuration offers higher maximum available power gain than the CE configuration in the device's high operation frequency range, while the inverse relation holds in the very low frequency range. The power gain difference, under different device stability conditions, between common-emitter (CE) and common-base (CB) bipolar junction transistors (BJT) is analyzed comprehensively.
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