Technology: Energetic transistor does two jobs for the price of one

日期:2019-02-28 06:13:08 作者:高唧谚 阅读:

By PETER HADFIELD in TOKYO Toshiba, the Japanese electronics company, claimed a breakthrough last week with a new type of transistor that is energy-efficient and can work at high voltages. Until now, transistors had one or other attribute but not both. The conventional metal oxide transistor is small and uses very little power. It also requires few peripheral parts, which means that it is lighter and less prone to break down. But metal oxide transistors cannot cope with the high voltages needed for applications requiring more power, such as the distribution of electricity or high-speed trains. For these uses, another type of transistor is used, the bipolar. The problem with bipolar transistors is their large energy consumption and their complexity – they need a large number of peripheral devices. Engineers have struggled for a long time to produce a new transistor that would combine the best qualities of both types. Toshiba says its new transistor, announced at the International Electron Devices meeting in Washington and called the Injection Enhanced Insulated Gate Bipolar Transistor, has all the advantages of the metal oxide transistors but can be used at high voltages. The key to the new transistor is a layer called the ‘carrier accumulation layer’, which reduces the voltage from 4500 volts to a couple of volts in the same way as a resistor does. Toshiba’s engineer in charge of developing the transistor, Makoto Ueda, says that the transistor ‘will be one tenth the size of the bipolar transistor, and require only about one-tenth the number of peripheral parts. That will mean an energy saving for high-power transistors of about 10 000 per cent.’ In the US the National Institute of Standards and Technology has just announced that it was contributing $2 million as part of a $5 million programme to develop a high-speed low-voltage transistor. Advanced Power Technology, of Oregon,