LONDON IBM Corp. has demonstrated what it said is the world's first thin-silicon SiGe bipolar transistor. It also announced a chip design that it said can improve performance four-fold while reducing power consumption five-fold in wireless devices.
The chip design uses a novel wafer thin enough to maximize the performance of both the computing and communicationscomponents.
IBM presented details of the chip design Tuesday (Sept. 30) at the 2003 Bipolar/BiCMOS Circuits and Technology Meeting in Toulouse, France.
IBM said the chip design could be implemented within five years, enabling applications such as anticollision radars in cars. The devices could also reduce power usage in cell phones and improve video streaming in mobile devices.
The achievement builds on IBM's recent announcement of design and manufacturing methods that improve the performance and lower the power consumption of pure computing chips.
IBM said it is the first to build SiGe bipolar using a thin SOI wafer, paving the way to processing SiGe bipolar and CMOS on the same thin SOI wafer.
Traditional SiGe bipolar transistors cannot be built on a thin SOI wafer. Until now, no technique existed to combine CMOS and SiGe bipolar onto one wafer that would maximize the performance of both.
The new process deposits a thin layer of SiGe on top of the SOI wafer, forming the basis for the bipolar transistor.
"Electrons come down from the polysilicon emitter, accelerate through the SiGe base and make a turn in the SOI layer towards the collector contact electrode," the company said. "With zero or low voltage applied to the SOI wafer, the current path in the SOI is long, which results in low electric field in the SOI and makes the device suitable for high voltage applications; with high positive voltage applied to the SOI wafer, the collector contact is virtually extended all the way to the back of the SOI layer under the emitter. The current path is thus shorter, making the device suitable for high speed applications."
The project is a collaboration between researchers at the IBM Semiconductor Research and Development Center, IBM Research and IBM Microelectronics Division.