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In this work, the surface recombination effect of a GaAs-based heterostructure-emitter and heterostructure-base transistor (HEHBT) with a pseudomorphic base structure are compared and investigated. Due to the insertion of InGaAs quantum well between emitter-base (E-B) junction, the valence band discontinuity can be enhanced and high emitter injection efficiency may be achieved. The excellent transistor characteristics including high current gain of 280 and low offset voltage of 100 mV are obtained when the base metal is deposited on the lower surface recombination velocity InGaAs layer. However, lower current gain of only 135 and large offset voltage of 300 mV are acquired as the base metal is deposited on the GaAs layer. This is mainly attributed to the significant difference of surface recombination effect of the studied devices. The surface recombination velocity of InGaAs is substantially lower than that of GaAs layer.

A high breakdown-voltage and high-linearity field effect transistor based on n-p-n structure, i.e., camel-gate field-effect transistor (CAMFET), has successfully fabricated and demonstrated. The CAMFET employs very thin n+ and p+ layers together with the channel to form a majority-carrier camel diode for modulating the channel current. The breakdown voltage about 21 V is obtained Furthermore, the maximum drain saturation current and transconductance are as high as 770 mA/mm and 220 mS/mm, respectively. Consequently, for the tri-step doping channel CAMFET, not only have the voltage-independent but also the high transconductance are obtained.