12 July 2011

Imec demos implant-free quantum-well SiGe pFETs 

Imec of Leuven, Belgium has fabricated implant-free quantum-well (IF-QW) pFETs with an embedded silicon-germanium (SiGe) source/drain.

The international nanoelectronics research center says that the devices show excellent short-channel control and record logic performance, with a benchmark against various competing technologies showing competitive results. The device performance was also demonstrated at low operating voltages. The results prove that the device architecture is a viable option for the 16nm technology node and beyond, Imec reckons.

Next-generation multimedia applications will require ICs that are simultaneously very powerful and low power, says Imec. An attractive option is to use high-mobility channels, for example using SiGe with high Ge content. However, further scaling of the gate length will require better electrostatic gate control, and low variability of the key electrical parameters. Imec and its partners have recently shown that the IF-QW concept with a buried SiGe channel meets these requirements while significantly improving the device performance.

Imec is now presenting the second generation of its SiGe45% IF-QW pFETs, processed on standard 300mm STI (shallow trench isolation) wafers. Compared to earlier IF-QW devices, the raised SiGe and Si substrate are recessed and replaced with a thick SiGe25% epi-layer to form the source/drain electrodes. Imec also says that it has developed process modules that minimize local variations and maximize the device performance.

These developments have resulted in what is described is excellent short-channel control, with a drain-induced barrier lowering of ~110mV/V at 35nm-LG and a record 1mA/µm-Ion at –1V. For lower operating voltages, increased performance was demonstrated.

The devices were benchmarked at various operating voltages against state-of-the-art technologies such as silicon-on-insulator (SOI) nFETs or SiGe-FETs, showing at least equivalent results. Imec reckons that these results show that SiGe IF-QW devices with an embedded source/drain form a promising architecture for integration on bulk silicon, from the 16nm node onwards.

The results were obtained in cooperation with Imec’s key partners in its core CMOS programs, including Globalfoundries, Intel, Micron, Panasonic, Samsung, TSMC, Elpida, Hynix, Fujitsu and Sony.

Imec is exhibiting in booth 1724 at this week’s Semicon West 2011 trade show in San Francisco, CA, USA.

Tags: Imec SiGe

Visit: www.imec.be