Electro-Thermal Model for Multi-Anode Schottky Diode Multipliers

Abstract

We present a self-consistent electro-thermal model for multi-anode Schottky diode multiplier circuits. The thermal model is developed for an n-anode multiplier via a thermal resistance matrix approach. The non-linear temperature responses of the material are taken into consideration by using a linear temperature-dependent approximation for the thermal resistance. The electro-thermal model is capable of predicting the hot spot temperature, providing useful information for circuit reliability study as well as high power circuit design and optimization. Examples of the circuit analysis incorporating the electro-thermal model for a substrateless-and a membranebased multiplier circuits, operating up to 200 GHz, are demonstrated. Compared to simulations without thermal model, the simulations with electro-thermal model agree better with the measurement results. For the substrateless multiplier, the error between the simulated and measured peak output power is reduced from ~ 13 % to ~ 4 % by including the thermal effect.

Modeling of Schottky barrier diode millimeter-wave multipliers at cryogenic temperatures

“…It is assumed that only the epi-layer resistance varies with temperature. In the developed SDD model the total series resistance is partitioned into two parts by using the parameter X r according to [7] ( ) ( …”

190 GHz high power input frequency doubler based on Schottky diodes and AlN substrate

“…Since the active layer of a diode anode is normally quite thin (on the order of several hundred nanometers), it is necessary to carefully optimize the diode properties which make it capable of handling certain power level of the driven input without causing the diode catastrophic failure due to the excessive input power. For the thermal issue, high input power will lead to higher operation temperature in the diodes, which adversely affects the circuit performance or even disables the diodes [9]. To tackle these two issues, the common strategy is to use more diode anodes to share the high input power, and to adopt high thermal conductivity materials as circuit substrates for rapid heat sink, respectively [10].…”

Submillimeter-Wave Quasi-Vertical GaAs Schottky Diodes Integrated on Silicon Membranes

“…Although this method cannot give temperature estimates for the individual diodes in the array, it does provide a measure of the approximate temperature rise of the devices when subjected to high input power levels. When driven at 100 mW for peak efficiency, the temperature of the varactors is estimated from these measurements to be 35°C, approximately 30°C lower than that calculated for the substrateless 100-200 GHz doubler and over 100 C cooler than the GaAs membrane multiplier investigated in [101], for the same input power.…”

“…Carrier velocity saturation will degrade a multiplier's performance at high applied voltages [15] and elevated temperatures increase the reverse saturation current of varactor diodes, contributing additional loss. Excessive heating is a significant issue for GaAs devices operating at submillimeter wavelengths as this material is generally a poor thermal conductor and is often thinned to only a few microns to mitigate excitation of substrate modes [101]. Consequently, researchers have directed significant effort towards improving the thermal grounding of these circuits, including bonding the GaAs-supported multipliers to highly thermal conductive substrates, such as diamond, to more efficiently remove heat [102].…”

“…To assess the reasonableness of the temperature estimations described above, thermal analysis of It should be added that the peak efficiency of the integrated multiplier presented in this work (60%) is a factor approximately 2.5 times larger than the multipliers presented in [101], and this high efficiency clearly impacts heat dissipation and temperature rise in the devices. The maximum input drive level tested for the circuit was 300 mW, which yielded an estimated diode temperature near 60°C.…”