Pulsed-mode high-power generation in silicon double drift region (DDR) IMPATT devices is briefly reviewed, and current work is presented on the structural parameter dependence of pulsed silicon IMPATTs designed for operation around 94 GHz at a current density of . Computer studies are presented on three DDR structures: (i) flat, (ii) SLHL, i.e. low - high - low structure with single bump on either side of the p - n junction, and (iii) DLHL, i.e. low - high - low structure with double bumps on either side of the p - n junction. The results indicate that the DLHL structures exhibit much higher negative conductance than the other structures. It is seen that the magnitude of the peak negative conductance of the DLHL DDR IMPATT devices decreases appreciably if low - high - low bumps are changed from rectangular to trapezoidal shape. It is also found that the heights of the second bumps produce little variation in the negative conductance of the DLHL device, although the second bumps play a vital role in containing the space-charge effect at high current densities. The heights of the first bumps close to the metallurgical junction, however, produce appreciable changes in the small-signal behaviour of the DLHL diodes. Further, it has been found that the width of the active region, if increased gradually, makes the DLHL diode a narrow band device operating near the avalanche resonance frequency. The effect of variation of bump width and bump location (from the optimized structure) on the high-frequency properties of the device has also been studied and the results are presented in the paper.

Studies on pulsed mm-wave low - high - low silicon IMPATT diodes at high current density and dependence on structural parameters

A review of the pulsed mode high power generation in silicon DDR IMPATT devices at high current density has been presented together with the current work of the authors in the same subject.Computer studies have been presented on silicon pulsed IMPATT diodes with various double drift region (DDR) structures for operation at 94 GHz at a current density of 100 KA/cm2. Three structures: (i) flat, (ii) SLHL, i.e., low-high-low structure with single bump on either side of the p-n junction and (iii) DLHL, i.e., low-high-low structures with double bumps on either side of the p-n junction have been investigated. The dc & small-signal results indicate that suitably designed silicon DDR IMPATT devices with double impurity bumps on either side of the junction exhibit much higher negative conductance and power output than other structures.It is seen that appropriately designed DDR structures could be operated at a high current density of 100 KA/cm2, with narrow avalanche zone to give sufficient W-band pulsed power, wh...

Computer Studies on Pulsed Silicon MM-Wave IMPATT Diodes for various DDR Structures at High Current Density

Computer studies have been carried out on the effect of electron and hole reverse saturation current on the high frequency (i) negative resistance and reactance profiles, (ii) admittance characteristics, and (iii) device quality factor of a silicon double-drift region (DDR) IMPATT operating in the mm-wave range (W-band). The results indicate that the negative resistance peaks in the electron and hole drift layers decrease with increasing reverse saturation current. The total diode negative resistance also decreases appreciably with the increase of either electron or hole reverse saturation current, ie, with decrease in electron or hole current multiplication factors (M & Mp).It has further been observed that in the lower frequency range of the W-band, the device negative conductance decreases with the increase of reverse saturation current, while in the frequency range from 160–210 GHz, the device negative conductance increases with the enhancement of reverse saturation current.An upward frequency shift b...

A Study on the Effect of Electron and Hole Saturation Currents on the Negative Resistance Profiles, Negative Conductance and the Frequency of Operation of Millimeter Wave (W-Band) Double-Drift Silicon IMPATT Diodes

N Mazumder

Papers

A Study on the Effect of Electron and Hole Saturation Currents on the Negative Resistance Profiles, Negative Conductance and the Frequency of Operation of Millimeter Wave (W-Band) Double-Drift Silicon IMPATT Diodes