Vitesse Semiconductor (distributed by Logic Four ) is to work with partners BAe Systems and the University of Illinois (UIUC) to fulfil a US$6 million ($8.75 million) contract from the US Defense Advanced Research Projects Agency (DARPA). The contract is to develop manufacturing processes and communication ICs using its sub-micron Indium Phosphide (InP) Heterojunction Bipolar Transmitter (InP HBT) technology.
Through the contract, the company will enhance the capabilities of its VIP-2 process. The process uses four-inch (102-mm) diameter semi-insulating substrates and is designed for high-performance and high yield. VIP-2 makes use of double heterojunction bipolar transistors working at twice the speed of the company’s current versions. The VIP-2 process has four layers of metal interconnect and includes resistors and capacitors. It provides designers the benefits of both high-speed and high-voltage operation suitable for digital, analogue and RF circuits at 10 GHz and higher.
Vitesse will collaborate with BAe on the design of communications chips. The initial devices are for direct digital frequency synthesis (DDFS) for defence and radar applications. Further transistor reduction is planned with the aim of shrinking device geometry to 0.25 μm. Vitesse claims that this will result in static speeds of 150 GHz.
Indium Phosphide (InP) is a member of the III-V family of semiconductors. III-V materials comprise one element from the metallic group 3 of the periodic table, and one from the non-metallic group 5. The family also includes Gallium Arsenide (GaAs) among others. The high electron mobility characteristics of InP and GaAs has led to the development of high electron mobility transistors (HEMT) such as Vitesse’s HBT devices.
In a HEMT the conducting channel is created by the heterojunction structure that confines the charge carriers to a thin layer. The concentration of the carriers and their speed in this layer enables the transistor to maintain its high gain at very high frequencies.
“Vitesse, BAe and UIUC embrace the opportunity to achieve the requirements DARPA has outlined and lead the charge for design improvements in their existing and future systems by using this emerging technology,” says Ray Milano, vice president of physical media devices at Vitesse.