Implant-free quantum-well SiGe pFETs for future high-performance CMOS architectures

Next-generation multimedia applications will require ICs that are at the same time very powerful and low power. One attractive option is to use high-mobility channels, for example using SiGe (silicon-germanium) with a high Ge content. However, further scaling of the gate length will require a better electrostatic gate control, and a 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 now presents the 2nd generation of SiGe45% IF-QW pFETs, processed on standard 300mm STI 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. Also, imec has developed process modules that minimize local variations and maximize the device performance.

This has resulted in an 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, an increased performance was demonstrated. The devices were benchmarked at various operating voltages against state-of-the-art technologies such as SOI nFETs or SiGe-FET, showing at least equivalent results. These results show that SiGe IF-QW devices with embedded source drain form a promising architecture for integration on bulk Si, from the 16nm node onwards.

These results were obtained in cooperation with imec’s key partners in its core CMOS programs Globalfoundries, INTEL, Micron, Panasonic, Samsung, TSMC, Elpida, Hynix, Fujitsu and Sony.

Provided by IMEC