Novel MOSFETs with Internal Block Layers for Suppressing Short Channel Effects and Improving Thermal Instability
In this paper, several new MOSFET devices, vertical MOSFET with L-shaped internal block layers (bVMOS), planar MOSFET with self-aligned internal block layers (bMOS), and Silicon-Germanium MOSFET with self-aligned internal block layers (bSGMOS) are presented. We use the sidewall spacer and etch back techniques to form the L-shaped internal block layers of bVMOS. They can suppress the short channel effects, diminish the parasitic capacitance, and reduce the leakage current cause by P-N junction between source/drain and body regions. They also provide a pass way to eliminate carriers and heat which generated by impact ionization resulting in suppression of floating-body effect and self-heating effect. In addition, we use Si3N4 cap layer upon gate as a hard mask, combining self-aligned and sidewall spacer techniques to fabricate the internal block layers under the both sides of channel end to form bMOS. The depleted region between source/drain and body is shielded and so the short channel effects and the controllability of gate to channel are improved. The internal block layers not only maintain the character of internal block layers but also ameliorate the drawback of bVMOS. The ISE TCAD simulation results show the short channel effect is suppressed and the thermal instability is improved by the internal block layers effectively in each device. Furthermore, we employ the epitaxial silicon-germanium thin film process (bSGMOS) to form silicon-germanium thin film at source/drain region to improve the device current drive by the strain thereby enhancing the device performance.
Advisor:Meng-Hsueh; Yao-Tsung Tsai; Ann-Kuo Chu; James B. Kuo; Jyi-Tsong Lin
School:National Sun Yat-Sen University
School Location:China - Taiwan
Source Type:Master's Thesis
Keywords:thermal instability block layer mosfet short channel effect
Date of Publication:08/21/2008