Microwave performance of optically fabricated T-gate thin film silicon-on-sapphire based MOSFET's

• Published in: IEEE electron device letters 1995-06, Vol.16 (6), p.289-292
• Main Authors: de la Houssaye, P.R., Chang, C.E., Offord, B., Imthurn, G., Johnson, R., Asbeck, P.M., Garcia, G.A., Lagnado, I.
• Format: Article
• Language: English
• Subjects: Applied sciences; Electronics; Exact sciences and technology; FETs; MOSFET circuits; Noise figure; Optical films; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Semiconductor films; Semiconductor thin films; Silicon on insulator technology; Thermal conductivity; Thermal stresses; Transistors; Voltage
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/55.790738

Microwave characteristics of n and p-MOS transistors fabricated in thin film (50 and 100 nm) silicon-on-sapphire with T-gate lengths drawn at 0.5 and 0.7 μm are reported. The observed f max was as high as 32 GHz for a n-MOS 0.7 μm gate length device. Minimum noise figure values of 1.4, 1.8, and 2.1 dB at 2, 8, and 12 GHz respectively were obtained in a 100 nm thick n-channel device. N-channel device results were comparable in the 50 and 100 nm films. For the p-channel FETs, the thinner, more highly stressed films gave significantly better results than the thicker p-channel films. At 2 GHz, p-FET noise figures as low as 1.7 dB were found. These results are, to the authors' knowledge, the lowest reported noise figures for either the p- or n-channel devices of any silicon based FET technology. Thinner films showed better voltage gain (g/sub m//g/sub out/) than the thicker films.