- 21 June 2005 -

Silicon is up from 103GHz to top 105-GHz

UMC, a world leading semiconductor foundry, today announced it has fabricated a Voltage-Controlled Oscillator (VCO) with a record-setting fundamental operating frequency of 105GHz using its 0.13um RF CMOS process technology.

The chip was developed by the Silicon Microwave Integrated Circuits and Systems Research Group (SIMICS), Department of Electrical and Computer Engineering at the University of Florida, Gainesville.

Until now, the highest recorded fundamental operating frequency for CMOS circuits was a 103-GHz oscillator fabricated using a 90nm CMOS process that consumed approximately four times more power.

The new effort by the University resulted in the 105-GHz VCO as well as a second 99-GHz VCO with a tuning range of 2.4 GHz, using the 0.13um process.

The effort signifies that VCOs for the 94GHz industrial scientific medical band and imaging as well as 60GHz WLAN and 77GHz radar applications can be implemented using UMC's process. VCOs are used in virtually all RF and wireless systems.

"UMC continues to provide the advanced process technologies that are used to power today's highest-performance applications," said Patrick T. Lin, chief system architect at UMC.

"Developing ICs of this caliber in 0.13um CMOS is a huge milestone," said Professor Kenneth O from the University of Florida. "If we incorporate frequency doubling techniques, we should be able to generate signals with 200 Ghz frequencies and higher.

"This has the potential to open up far-infrared to CMOS. UMC's role in our development was pivotal as this leading foundry provided the process and parameters that brought the chip to silicon quickly and easily."

The 105-GHz VCO uses a cross-coupled NMOS transistor core. The transistor structure of the LC resonator-based VCO chip has been optimised to reduce parasitic capacitances, which limits the maximum operating frequency.

An accumulation mode MOS varactor has been optimised to achieve Q values of approximately 6 at 105GHz or approximately 630 at 1GHz, which is critical for achieving low power consumption and reducing noise.

The 99-GHz VCO core consumes 15 mW. The phase noise at 10-MHz offset from the carrier varies between -101 to -103 dBc/Hz over the 2.4-GHz tuning range. The circuits were developed with the support of DARPA.