In the last couple of years, Rohm Semiconductor has dug trenches to fortify its budding silicon carbide business, which is trying to replace the conventional silicon used in power electronics. Last year, the company did so literally.
The Japanese chipmaker said that it would start manufacturing the first silicon carbide MOSFETs carved with tiny trenches, which provide much lower resistance and faster switching speeds than previous circuits.
Now, the company is displaying the devices this week at the Electronica trade show in Munich, Germany. In 2010, Rohm was the first to start manufacturing silicon carbide MOSFETs and now it's on the third generation of the technology.
Silicon carbide is also known as a wide-bandgap material, which can typically handle higher voltages and tolerate much hotter temperatures than regular silicon. Chipmakers like Cree and Infineon are using it in light bulbs and power electronics inside things like electric car charging stations.
But the unorthodox material has seen limited success. The factors that have constrained the market include the high cost of packaging the material and the difficulty of integrating it with conventional parts. Sales of the silicon carbide devices have not progressed as quickly as many analysts predicted.
Rohm’s devices cut resistance in half and input capacitance by 35% in the same size chip as silicon carbide devices without the microscopic trenches. They are designed to handle low and medium voltages, and their faster switching speed allows engineers to pair them with smaller coils and capacitors.
The company is also showing new Schottky barrier diodes built out of silicon carbide, with high switching speeds for power supplies. Other products on display at Electronica include power modules containing the diodes and MOSFETs.