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 (delta(n)) layer and a delta-p (delta(p)) layer is proposed and fabricated. Electrons are confined in the upper undoped- GaAs layer (the channel layer) rather than around the delta(n) layer b y the influence of the transverse electric field resulting from the di pole-barrier formation. This leads to the high electron concentration of 1.5x10(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 mu m gate length shows the maximum value of extrinsic transconductance of 366 mS/mm. The drain current density is larger tha n 800 mA/mm. The current gain cutoff frequency f(T) of 16.7 GHz and th e maximum oscillation frequency f(max) of 67 GHz are obtained. One-dim ensional calculation of device characteristics is performed for the pu rpose of evaluating the device performance.