Power static induction transistor technology

Static induction transistor (SIT) is characterized by short channel structure and the relatively low impurity concentration in the channel, so that the potential profile near the source region is effectively controlled by the drain voltage as well as the gate voltage. Majority carriers in the source region are directly injected into the channel and their amount continuously increases with increasing the drain voltage, thus establishing the non-saturating current-voltage characteristic in the SIT. The SIT, which is usually constructed as a vertical multichannel structure, exhibits features such as high input impedance, small gate capacitance, small gate resistance and negative temperature coefficient of drain current, thus offering a thermally stable operation of large area devices without ballasting resistor. An introduction of high resistivity region between gate and drain increases its breakdown voltage and decreases gate to drain capacitance, leading to an improvement of handling power and frequency characteristic.