Title :
Increased hot-carrier effects 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 drain can modify hot-carrier characteristics via material dependent impact ionization coefficients. MOSFETs with ramped SiGe drain layers showed increased drain current in the soft breakdown regime, due to increased impact ionization as verified by substrate current measurement, with up to 1.5 V decreases in breakdown voltage. Comparison of simulation to experiment displayed the difficulties of accurately predicting device parameters, but demonstrated the usefulness of simulation to qualitatively predict device behavior without costly expenditures of time, material, and equipment
Keywords :
Ge-Si alloys; MOSFET; avalanche breakdown; hot carriers; impact ionisation; semiconductor device breakdown; semiconductor device models; I-V characteristics; SiGe; SiGe heterostructures; avalanche breakdown; breakdown voltage; current-voltage characteristics; drain engineering; hot-carrier characteristics; material dependent impact ionization coefficients; ramped SiGe drain layers; simulation; soft breakdown regime; vertical MOSFET drain; vertical surrounding gate MOSFETs; Charge carrier processes; Electrons; Germanium silicon alloys; Hot carrier effects; Hot carriers; Impact ionization; MOSFETs; Predictive models; Silicon germanium; Voltage;
Journal_Title :
Electron Devices, IEEE Transactions on
