Hole-trapping/hydrogen transport (HT) sup 2 model for interface-trap buildup in MOS devices
The electric field dependence of radiation-induced interface-trap formation has been reported to be different for metal-gate capacitors and polysilicon-gate capacitors and transistors. For metal-gate capacitors, interface-trap formation steadily increases with increasing positive field. On the other hand, for polysilicon-gate capacitors and transistors, interface-trap buildup peaks near fields of 1 MV/cm to 2 MV/cm and decreases with an approximate E{sup {minus}1/2} dependence at higher fields. The previously reported field dependence for interface-trap generation for Al-gate capacitors is consistent at all fields with McLean's physical explanation of the two-stage process, which depends on hydrogen ion (H {sup +}) release in the bulk of the oxide as radiation-induced holes transport to either interface via polaron hopping. Above 1 MV/cm, the field dependence of interface-trap buildup for polysilicon-gate devices is inconsistent with this model. Instead, it is similar to the field dependence for hole-trapping in SiO{sub 2}, suggesting that hole trapping may play a key role in interface-trap generation in Si-gate devices. However, recent studies of the time-dependence of interface-trap buildup have known that hole trapping cannot be the rate-limiting step in interface-trap buildup in polysilicon gate devices. Consistent with McLean's physical explanation of the two-stage process, the rate-limiting step in interface-trap formation appears to be H{sup +} transport to the Si/SiO{sub 2} interface. We will show that the electric field dependence of radiation-induced oxide- and interface-trap charge buildup for both polysilicon and metal-gate transistors follows an approximate E{sup {minus}1/2} field dependence over a wide range of electric fields when electron-hole recombination effects are included. Based on these results a hole trapping/hydrogen transport (HT){sup 2} model for interface-trap buildup is proposed.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (USA)
- Sponsoring Organization:
- DOE/DP
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 6763446
- Report Number(s):
- SAND-90-2291C; CONF-901235--2; ON: DE91000020
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
426000* -- Engineering-- Components
Electron Devices & Circuits-- (1990-)
656002 -- Condensed Matter Physics-- General Techniques in Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BARYONS
CATIONS
CHARGED PARTICLES
ELECTRIC FIELDS
ELEMENTARY PARTICLES
FERMIONS
HADRONS
HOLE MOBILITY
HOLES
HYDROGEN IONS
HYDROGEN IONS 1 PLUS
INTERFACES
IONS
MOBILITY
MOS TRANSISTORS
NUCLEONS
PROTONS
RECOMBINATION
SEMICONDUCTOR DEVICES
TRANSISTORS
TRAPPED PROTONS
TRAPPING