Increasing consumer demand for low power portable products is being answered by Motorola, Inc.'s Semiconductor Products Sector (SPS), with improvements to its silicon germanium carbon (SiGe:C) technology for wireless applications. Motorola's latest performance enhancement to its 0.18 and 0.35 micron SiGe:C heterojunction bipolar transistor (HBT) in a BiCMOS process is expected to provide longer battery life, meaning longer talk times for portable products including cellular phones.
This enhancement was presented this week at IEEE's Bipolar/BiCMOS Circuits and Technology Meeting (BCTM). By optimizing the way the transistor is built, power consumption may be reduced by a factor of four, and a 60 percent improvement in peak frequency performance may be obtained, in comparison with the existing process.
"Our full suite of passives along with RF/analog MOS and optimized silicon germanium carbon are designed to enable new products while allowing current reduction in existing products," said Dr. Vida Ilderem, director of RF/IF silicon technologies for Motorola. "High integration and low cost make this technology very attractive for wireless handset applications."
Silicon germanium allows for the integration of multiple functions onto a single chip. This optimized chip-making process helps to further conserve power consumption, while improving performance. Motorola's process integrates a high performance HBT with CMOS analog and digital functions on a single chip. Because the development was done on existing technology platforms, designers can use the existing models, libraries and standard cell designs for the 0.18 and 0.35 micron BiCMOS processes.
Cutoff frequencies have been improved from 50 GHz to 80 GHz (0.35 micron BiCMOS) and 120 GHz (0.18 micron BiCMOS) with a reduction in minimum noise figure from 0.9 dB to 0.3 dB. This performance was realized through vertical and lateral scaling of the transistors.
"These significant improvements in power consumption and RF noise boost the capabilities of an already leadership technology," said Behrooz Abdi, vice president and general manager of Motorola's Radio Products Division. "These are key metrics for the wireless mobile market. They are intended to enable our existing and future customers to offer leadership products to the cellular, wireless LAN and GPS markets with unprecedented levels of integration."
Motorola has introduced several products using its first-generation 0.35 micron SiGe:C process including the RF portion of its i.250 GSM/GPRS Innovative Convergence' wireless platform. The 0.18 micron process was qualified in the first quarter of 2002, with products planned for early 2003.