Smallest Jazz process offers lean, green chips
by Andy Extance in Atlanta
Jazz Semiconductor has quadrupled the cutoff frequency that chips made in its SiGe fab can achieve, boosting its challenge to rival silicon and GaAs technologies.
By cutting the size of its lithographic process from 0.35 µm to 0.18 µm the Newport Beach, California, company has boosted peak cutoff frequency, fT, from 50 GHz to 200 GHz.
This enhances the advantage that devices made with the process have over RF CMOS, and can convert to energy efficiency improvements where high frequencies aren t needed. At the International Microwave Symposium in Atlanta, Georgia, on June 17, Jazz claimed that 0.18 µm SiGe fabrication can now provide a 30 percent efficiency advantage over silicon.
“Before, 1 mA could get you performance at 50 GHz. Now, you re doing it for tens of milliamps instead of one,” explained Todd Mahlen, manager of Jazz s power management service.
Even with the new process in place, Jazz feels that GaAs retains a strong hold on applications at frequencies above 5 GHz. However it is confident it can compete below 5 GHz, and can more readily integrate different functions in CMOS. That includes the possibility of integrating a silicon transceiver, with an RF power amplifier, switch and logic functionality.
This integration has been aided by a new process based on a layer of n-doped SiGe sandwiched vertically between two p-doped SiGe layers, christened vertical PNP .
“Vertical PNP does precision analog functions like data conversion and timing,” Mahlen said. “Having a vertical PNP to complement our high-speed, high-end NPN is very attractive, there s really nobody out there that is selling that today.”
Jazz s capability to promote this unique chip manufacturing approach looks set for a boost thanks to its impending buyout by Tower Semiconductor. Israel-based Tower is an exclusively silicon foundry that might seem an unexpected bedfellow for Jazz, but Mahlen is positive about the match.
“The attractive thing for us is really economy of scale,” he said. “It makes us a sizeable player where the big guys can take us more seriously.”
“In our top 20 customers we have no overlap. In the top 50 we have only three.”
Combining Tower s 6 and 8-inch wafer lines in Israel and Jazz s 8-inch line, plus two Chinese joint ventures that Jazz is involved in, will allow the overall company to produce the equivalent of 750,000 8-inch wafers annually. This will equate to the seventh largest pure-play foundry and the largest specialty foundry in the world.
The merger is expected to be completed in the closing quarter of 2008.
Andy Extance is a reporter for compoundsemiconductor.net.