Investigation on Heat Transfer Mechanism of Semiconductor Bridge Ignition Based on Thermoelectric Coupling Analysis

The heat transfer mechanism in the electroexploding ignition process of the semiconductor bridge (SCB) is studied by finite element simulation to reveal the ignition mechanism of SCB, and the ignition threshold voltage of SCB is predicted by the critical ignition heat Q(c). The thermoelectric coupling model is adopted to analyze the distributions of temperature and electric field intensity for the SCB. Under the capacitor discharge of 30 V, the temperature distribution is not uniform of the bridge, and the temperature rises fastest at the "heat points" formed at the V-shaped sharp corners. The highest electric field intensity also appears first at the V-shaped sharp corners, and then the electric field intensity concentrates the edge of the melted zone greatly increasing the heat generation in the un-melted zone. Since the melted zone enlarges with the propagation of the electric field intensity, the heat transfer during the ignition process can be attributed to the coupling effect caused by the thermal and electric fields. After the Q(c) of SCB is calculated from the enthalpy value corresponding to the phase changes of melt and vaporization, the heat generation Q(r)-t curves are used to determine the ignition threshold voltage of 21 V for the specific size SCB device by comparing with the Q(c) value. This method could be used to predicate the ignition threshold voltage of the electroexploding ignition for various types of SCB, so it is very important for guiding the design of SCB in practical applications.