A new GaAs field effect transistor (FET) with DIpole barrier (DIB)

A new GaAs field effect transistor (FET) with dipole-barrier (DIBFET) employing a delta- n (δ n ) layer and a delta- p (δ p ) layer is proposed and fabricated. Electrons are confined in the upper undoped-GaAs layer (the channel layer) rather than around the δ n layer by the influence of the transverse electric field resulting from the dipole-barrier formation. This leads to the high electron concentration of 1.5×10 18 cm -3 with the electron drift mobility of 3600 cm 2 /V·s in the undoped GaAs channel at room temperature. The fabricated GaAs DIBFET with 0.8 µm gate length shows the maximum value of extrinsic transconductance of 366 mS/mm. The drain current density is larger than 800 mA/mm. The current gain cutoff frequency f T of 16.7 GHz and the maximum oscillation frequency f max of 67 GHz are obtained. One-dimensional calculation of device characteristics is performed for the purpose of evaluating the device performance.