A European consortium is aiming to create an integrated circuit with advanced silicon-based bipolar transistors that operate at a frequency of 500GHz, or 0.5Tera Hertz, as part of an £11 million project.

Gilles Thomas, of STMicroelectronics, co-ordinator of the DOTFIVE project, explained: “The objective is to develop silicon/germanium heterojunction bipolar transistors (SiGe HBTs) at 500GHz, which could allow the design of products with circuits that could reach up to 160GHz. This compares with devices such as today’s GSM phones, which operate at a standard frequency of 2GHz in Europe.

A key part of the new transistor will be the silicon germanium compound, built on a substrate of pure silicon, which allows the band gap of the semiconductor material to be widened. This is designed to enable higher mobility of the electrons and consequently higher transistor frequencies. The researchers also plan to explore new ways of building the transistors.

According to Thomas, the transistors will allow for applications that are currently only available using very costly techniques — either electronics comprising expensive compound materials like gallium arsenide or indium phosphide, or by using discrete electronics.

Thomas continued: “You could have applications such as proximity radars, which currently work at 77GHz and are being developed on very high-end cars, and radars with a range of distances to increase safety, especially in poor visibility.

“You could also, for example, cheaply build airport security equipment to detect weapons on people without them having to remove any clothing.”

The 36-month project is scheduled to end in 2010.

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