Heinz Schmid, Hans Biebuyck, et al.
Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Excellent improvement in the hole transport properties for SiGe heterostructures promises symmetric, higher speed, and lower power consumption circuits compared to conventional Si CMOS devices. Modulation-doped field effect transistors (MODFETs) grown on a relaxed Si0.7Ge0.3 buffer have been fabricated using a self-aligned gate process. The p-type devices had gate lengths ranging from 1.0 μm down to 0.1 μm. A record unity current gain cutoff frequency fT of 70 GHz was obtained for 0.1 μm gate-length devices.