Novel UK Si transistor switches 1.2kV and 75A through a TO247 package

It has a TO-247 transistor switching 1.2kV and 75A.

“To get this level of performance from traditional silicon-based mosfets, the device size must be much bigger,” said SFN CEO and founder David Summerland. “1,200V 75A in a TO247 housing can be achieved using wide bandgap materials like silicon carbide, but this approach has other issues – SiC, for example, takes much longer to process [and] regardless of the roadmaps, SiC does not scale like silicon.  The production equipment required to make a QJT is exactly the same as for a standard silicon mosfet, and the Bizen process adds no extra manufacturing complexity.”

The company initially plans three parts in TO-247 or TO-263: 1200V 75A, 900V 75A and 650V 32A, which will be able to be made on “conventional larger-geometry silicon processing lines”, according to the company.

Also mooted is a 1.2kV 100A TO-247 transistor, with the company saying: losses at rated current will be one quarter (<300mV) of those exhibited by the SiC device, and its input capacitance will also be four to five times less (<1pF).

Wafer tests also show that the Bizen process exhibits an effective current gain of over 1 million, said SFN, which “will enable direct connection between the 1,200V/ 75A QJT power transistor and a low-voltage low-current CPU output port such as a PWM.

“The QJT is the first power device on the Bizen family roadmap,” said Summerland. “This will shortly lead to the ‘processor junction transistor [PJT], an integrated Bizen device with its own processor, which can also be produced on a manufacturing cycle time of eight days, heralding a new era of intelligent power devices.”

This short manufacturing cycle is due to the small number of masks needed to make the transistors, even with integrated logic.

Bizen parts are being made at Semefab in Nottinghamshire.

Search For The Next’s trading arm is a subsidiary called WaferTrain, which operates the Bizen blog – which requires a log in to read it.