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The breakdown behavior of a heterodimensional two-dimensional MESFET has been investigated. It is a novel side-gated FET made from a double-sided planar-doped AlGaAs/InGaAs PHEMT material. Its on-state breakdown behavior reduces impact ionization at high drain-source bias leading to a low output conductance of less than 6 mS/mm for V(sub GS) = 0 V and a low gate leakage current of less than 100 nA. Its off-state drain-source and drain-gate breakdown voltages were measured to be at 20 and 21 V.

A survey of the optoelectronic response of sidegated 2-D MESFET's utilizing laterally contacting gates to the active region shows broad photoresponse that may be tuned by the applied gate bias. These MESFET's also exhibit a higher responsivity that may be attributed to the top illumination unimpeded by the top gate. The survey reveals photogains as high as 2.4 X 10(super 7) at 0.7 micrometer wavelength and 26 microwatt/sq cm optical power intensity. The contact of the gates with the sides of the photoactive region eliminates the shadowing effect so as to permit direct illumination of the channel.

A quasi-three-dimensional method models novel semiconductor devices, such as a two-dimensional metal semiconductor field effect transistor (MESFET). It uses a two-dimensional numerical simulation of device cross-section under different gate biases, and an analytical model representing the current and potential distribution in the third dimension. The application of interpolated results of numerical simulation to analytical theory yields the relation between threshold voltage and device dimensions, between device conductance and gate voltage, and an estimate of the full channel current.

Fabricates a quarter-micrometer diameter Schottky barrier mixer diode on n[sup +] gallium arsenide. Formation of anodes; Growth of layers by chemical vapor deposition; Measurement of diode zero-bias capacitance; Observation on the video responsivity of the diodes; Description of the diode design, fabrication and evaluation.