On the n/sup +/-InGaAs/n-GaAs composite doped channel heterostructure field-effect transistor (CDC-HFET)

An interesting n/sup +/-InGaAs/n-GaAs composite doped channel heterostructure field-effect transistor (CDC-HFET) is fabricated and studied. In the n/sup +/-InGaAs/n-GaAs CDC structure, the narrow InGaAs layer is used to introduce the channel quantization effect. Thus, the effective energy-gap of InGaAs channel can be increased. In addition, the n-GaAs channel can improve the operation capability under higher electric field. Therefore, the impact ionization effect can be avoided. Experimentally, the studied device shows good DC and microwave dc performances with flat and wide operation regime.