Title :
Suppression of the floating-body effect using SiGe layers in vertical surrounding-gate MOSFETs
Author :
Date, Celisa K. ; Plummer, James D.
Author_Institution :
Paul Allen Center for Integrated Syst., Stanford Univ., CA, USA
fDate :
12/1/2001 12:00:00 AM
Abstract :
The use of silicon germanium (SiGe) heterostructures in vertical surrounding-gate MOSFETs provides an additional means for tailoring current-voltage (I-V) characteristics by controlling physical effects inside the device. Incorporation of an SiGe layer in the vertical MOSFET source can delay the floating-body effect by changing the back injection efficiency and current gain of the parasitic bipolar junction transistor (BJT). Structures with abrupt and ramped SiGe source layers showed up to 2 V and 6 V increases in breakdown voltage at low gate voltages with suppression of the floating-body effect kink. Comparison of simulation to experiment displayed the difficulties of accurately predicting device parameters, but demonstrated the usefulness of simulation to qualitatively predict device behavior
Keywords :
Ge-Si alloys; MOSFET; avalanche breakdown; semiconductor device breakdown; semiconductor device models; I-V characteristics; MEDICI simulator; SiGe; SiGe heterostructures; SiGe layer; abrupt SiGe source layers; avalanche breakdown; back injection efficiency; breakdown voltage; current gain; current-voltage characteristics; floating-body effect kink; floating-body effect suppression; parasitic BJT; parasitic bipolar junction transistor; ramped SiGe source layers; source engineering; vertical MOSFET source; vertical surrounding-gate MOSFETs; Acceleration; Electric breakdown; Germanium silicon alloys; Impact ionization; MOSFETs; Photonic band gap; Predictive models; Random access memory; Silicon germanium; Substrates;
Journal_Title :
Electron Devices, IEEE Transactions on
