Automotive-qualified SiC DMOSFETs with integrated Schottky Rectifiers

Reducing the size, weight, and increasing the efficiency of automotive traction power inverters requires the development of novel high-voltage, high current silicon carbide high-speed transistors and rectifiers, since the existing silicon technology is severely limited in terms of operating temperature, frequency and energy efficiency. However, the non-optimized device and manufacturing technology currently used for silicon carbide power diode fabrication results in higher energy losses and a non-competitive price point with respect to silicon. Novel device and process technology in combination with the use of a high-volume manufacturing strategy on large diameter silicon carbide wafers is proposed in this proposed program for achieving near-theoretical device performance on high-current power transistors with integrated Schottky rectifiers. The proposed device and manufacturing strategies will drastically reduce the manufacturing costs for silicon carbide Schottky diodes and transistors, making them cost- competitive with the existing silicon technology. Phase I was focused on a proof-of-concept demonstration of the proposed device technology. A major task involved transferring the process technology to a large-scale, high- volume foundry identified in the proposal. Phase II will be focused on scaling the voltage and current ratings of the Phase I demonstrated device to 1700 V and up to 250 Amperes, in line with updated requirements from automotive customers. Detailed reliability investigations pursuant to the industry standards is planned for Phase II. A detailed commercialization strategy will also be implemented during Phase II. Commercial Applications and Other Benefits: John Deere is extremely interested in the proposed devices in this program for their next generation of heavy-duty construction vehicles. Electric vehicle power electronics manufacturers such as General Motors, Delphi Automotive and Cummins Power Systems are expected to be direct customers of the proposed silicon carbide devices to be developed in this program. Reducing the weight of the power module, which represents 23% of the total Inverter weight will extend its electric range and/or reduce the size and cost of the battery. Significantly reduced silicon carbide chip-sizes for the same current rating along with low-cost, high-volume manufacturing strategies proposed in this program will help meet the aggressive power electronics targets set for the electric vehicle industry by the DOE for the year 2022. This in turn will enhance the country’s energy security by reducing dependence on foreign oil, save money by cutting fuel costs for American families and businesses, and result in a cleaner environment by reducing harmful CO2 emissions from gas- powered vehicles.