Effect of punch through on the microwave series resistance of n⁺np⁺Si IMPATT diodes around the X band

Abstract

The effect of punch through on the series resistance of n + np + single drift region Si HP [5082-0432] IMPATT diodes of capacity 0.02 pf around the X band has been studied. The computed result for series resistance fits well with the device data. The analysis shows that for a constant bias current density, when the space charge effect is not prominent, the value of series resistance decreases with the decrease of punch through, determined by the doping density and thickness of the active layer. The decrease of punch through produces an upward shift in the operating frequency of the device. It is also observed that an increase of punch through factor leads to a decrease in negative resistance, conversion efficiency and the susceptance of the device.