High-frequency characterization of the charge injection transistor

High frequency measurements on the three terminal device based on real-space hot electron transfer between two conducting layers separated by a potential barrier have been performed. The device was made from a multilayer GaAs/AlGaAs heterostructure grown by OMCVD. When operating as a charge injection transistor the device exhibits power and current gains with cut-off frequencies of ∼9.8 and ∼29 GHz, respectively. The maximum current gain was ∼40 dB. In the negative resistance FET mode the same device was found to be capable of microwave generation in the frequency range up to 7.7 GHz. The frequency response of our device is shown to be limited by RC in the output circuit and methods for improvement of cutoff frequency are discussed.