摘要
A full-scale, self-consistent, non-linear, large-signal model of double-drift hetero-structure IMPATT diode with general doping profile is derived. This newly developed model, for the first time, has been used to analyze the large-signal characteristics of hexagonal SiC-based double-drift IMPATT diode. Considering the fabrication feasibility, the authors have studied the large-signal characteristics of Si/SiC-based hetero-structure devices. Under small-voltage modulation （~ 2%, i.e. small-signal conditions） results are in good agreement with calculations done using a linearised small-signal model. The large-signal values of the diode＇s negative conductance （5 × 106 S/m2）, susceptance （10.4 × 107 S/m2）, average breakdown voltage （207.6 V）, and power generating efficiency （15%, RF power： 25.0 W at 94 GHz） are obtained as a function of oscillation amplitude （50% of DC breakdown voltage） for a fixed average current density. The large-signal calculations exhibit power and efficiency saturation for large-signal （〉 50%） voltage modulation and thereafter decrease gradually with further increasing voltage-modulation. This generalized large-signal formulation is applicable for all types of IMPATT structures with distributed and narrow avalanche zones. The simulator is made more realistic by incorporating the space-charge effects, realistic field and temperature dependent material parameters in Si and SiC. The electric field snap-shots and the large-signal impedance and admittance of the diode with current excitation are expressed in closed loop form. This study will act as a guide for researchers to fabricate a high-power Si/SiC-based IMPATT for possible application in high-power MM-wave communication systems.
A full-scale, self-consistent, non-linear, large-signal model of double-drift hetero-structure IMPATT diode with general doping profile is derived. This newly developed model, for the first time, has been used to analyze the large-signal characteristics of hexagonal SiC-based double-drift IMPATT diode. Considering the fabrication feasibility, the authors have studied the large-signal characteristics of Si/SiC-based hetero-structure devices. Under small-voltage modulation （~ 2%, i.e. small-signal conditions） results are in good agreement with calculations done using a linearised small-signal model. The large-signal values of the diode＇s negative conductance （5 × 106 S/m2）, susceptance （10.4 × 107 S/m2）, average breakdown voltage （207.6 V）, and power generating efficiency （15%, RF power： 25.0 W at 94 GHz） are obtained as a function of oscillation amplitude （50% of DC breakdown voltage） for a fixed average current density. The large-signal calculations exhibit power and efficiency saturation for large-signal （〉 50%） voltage modulation and thereafter decrease gradually with further increasing voltage-modulation. This generalized large-signal formulation is applicable for all types of IMPATT structures with distributed and narrow avalanche zones. The simulator is made more realistic by incorporating the space-charge effects, realistic field and temperature dependent material parameters in Si and SiC. The electric field snap-shots and the large-signal impedance and admittance of the diode with current excitation are expressed in closed loop form. This study will act as a guide for researchers to fabricate a high-power Si/SiC-based IMPATT for possible application in high-power MM-wave communication systems.
