Title :
Design of nearly body-effect free Si/SiGe MODFETs
Author :
Velázquez, J.E. ; Jeamsaksiri, W. ; Yeoh, J.C. ; Fobelets, K.
Author_Institution :
Dept. of Electr. & Electron. Eng., Imperial Coll. of Sci. Technol. & Medicine, London, UK
Abstract :
DC transfer characteristic measurements have been carried out on an n-channel Si/SiGe MODFET with an MOS gate at three different substrate biases. For our layer structure, electrons are supplied into the strained Si quantum well (QW) from the top heavily doped layer and below the QW is non-intentionally doped (setback). Here, we numerically studied the setback layer, for which the doping can be systematically designed to reduce the influence of the substrate bias on the threshold voltage (VTH) shift. By inserting and positioning a 15 nm-thick heavily doped n+ (2.10(-7) cm-3) layer into the 700 nm-thick setback layer, we found that, when we positioned the n+ layer 635 nm below the QW, the VTH shifted by only 37 mV and only a slight change of the subthreshold slope occurred, 3.12 mV/dec, for -2 V applied to the substrate
Keywords :
Ge-Si alloys; elemental semiconductors; heavily doped semiconductors; high electron mobility transistors; microwave field effect transistors; semiconductor materials; silicon; DC transfer characteristic measurements; MOS gate; Si-SiGe; Si/SiGe MODFETs; heavily doped layer; n-channel MODFETs; nearly body-effect free MODFETs; setback layer; strained Si quantum well; substrate bias; subthreshold slope; threshold voltage shift; Doping; Educational institutions; FETs; Germanium silicon alloys; HEMTs; MODFET circuits; MODFET integrated circuits; MOSFET circuits; Silicon germanium; Threshold voltage;
Conference_Titel :
High Performance Electron Devices for Microwave and Optoelectronic Applications, 2000 8th IEEE International Symposium on
Conference_Location :
Glasgow
Print_ISBN :
0-7803-6550-X
DOI :
10.1109/EDMO.2000.919023
