Future and Limits of Power I.C.

In this paper we present a review of the actual realizations and future trends for the power IC technologies. Two different processes for high voltage and high current are discussed and compared. Particular attention is devoted to surface stability phenomena and their implications on reliability. The actual panorama for medium and high power packages is discussed. Starting from the phisical limit of the maximum power that can "be dissipated in practical application conditions, we analyse the maximum power available at the out put for three classes of operations: DC, AC audio, and class D switching amplifiers. For the first two applications the actual limits appear to be set mainly by the extermal context (power supply regulation, thermal heatsink capability) instead of electrical performance of the silicon chip itself. So the actual implementations that provide 30 W continuous power and a voltage-current product in excess of 200 W, appear as a maximum. Class D limits appear to be mainly connected to the intrinsic characteristics of power devices, like sustaining-saturation voltage ratio, commutation speed and 2nd breakdown ruggedness. Actual implementations in 44 V technology reach 80 W for bipolar loads, so 150 W are possible when considering unipolar loads. But the new developments in power technologies indicate the way how to increase them.