Optically driven photoconductive devices for power switching application. II. Thermal modelling including heat sink

For pt.I see ibid., vol.139, no.3, p.343-9 (1992). The removal of heat generated in power devices using a heat sink is increasingly important for packaging and reliability, particularly for the photoconductive circuit element (PCE) which can conduct a large current when used as a high power switch. The authors present a thermal model for estimating the relationship between the temperature in a p ⁺-i-n⁺ PCE and the required geometry of the heat sink under steady-state dark and illuminated operations. The model is based on a one-dimensional heat-transfer analysis and relevant semiconductor device physics. Given the bias condition, the geometry and the material for the PCE, and the material for the heat sink, the model can predict the area of the heat sink needed for a desired temperature in the device. Calculations for different semiconductor thicknesses, different metals (aluminum and copper), different semiconductors (Si and GaAs), different applied voltages, different levels of optical excitation and different device operations (turn-on and turn-off operations) are illustrated