Details

Autor(en) / Beteiligte

• Hellberg, P.-E
• Zhang, S.-L
• Radamsson, H.H
• Kaplan, W

Titel

Threshold voltage control for PMOSFETs using an undoped epitaxial Si channel and a p+-SixGe1−x gate

Ist Teil von

• Solid-state electronics, 2000-11, Vol.44 (11), p.2085-2088

Erscheinungsjahr

2000

Quelle

Elsevier Journal Backfiles on ScienceDirect (DFG Nationallizenzen)

Beschreibungen/Notizen

• This paper examines experimentally the performance of PMOSFETs with an undoped epitaxial Si channel in combination with a p(+)-SixGe1-x gate electrode. The channel doping profiles were made using shallow As-implantation followed by selective epitaxy of undoped Si to different thicknesses of 40, 80 and 120 nm. The p(+)-SixGe1-x gate with different values of x was used to tailor the threshold voltage. The transconductance and saturation current were found to increase and the threshold voltage to decrease with increasing thickness of the undoped Si channel for the same gate material. Increasing Ge content in the p(+)-SixGe1-x gate resulted in an increased threshold voltage. Compared to the p(+)-Si gate, the threshold voltage was increased by 0.15 and 0.35 V with a p(+)-Si0.79Ge0.21 and p(+)-Si0.53Ge0.47 gate, respectively, independently of the Si channel thickness. Therefore, the use of a p(+)-SixGe1-x gate introduces an extra degree of freedom when designing the channel for high performance PMOSFETs.