METHOD OF BUILDING A DISTRIBUTED POWER DEVICE WITH DUAL FUNCTION MINORITY CARRIER REDUCTION

摘要

A distributed power device (100) including a plurality of tank regions (90) separated from one another by a deep n-type region (16), and having formed in each tank region a plurality of transistors (50). The plurality of transistors (50) in each tank region are interconnected to transistors in other tank regions to form a large power FET, whereby the deep n-type regions isolate the tank regions from one another. A first parasitic diode (D5) is defined from each tank region to a buried layer, and a second parasitic diode (D4) is defined between the buried layer and a substrate. The deep n-type regions distribute the first and second parasitic diodes with respect to the plurality of tank regions, preferably comprised of a P-epi tank. The deep n-type regions also distribute the resistance of an NBL layer (14) formed under the tank regions. The distributed parasitic diodes and resistance of the NBL layer advantageously provides that the parasitic diode (D4) between the NBL layer and the substrate will never be forward biased. In addition, each of the tank regions has a heavily doped p-type region (56) reducing the minority carrier lifetime to provide increased switching speed of the large power FET.