Accession Number:

AD0648236

Title:

RADIATION STUDY ON MOS STRUCTURES,

Descriptive Note:

Corporate Author:

FAIRCHILD CAMERA AND INSTRUMENT CORP MOUNTAIN VIEW CALIF FAIRCHILD SEMICONDUCTOR DIV

Report Date:

1967-01-01

Pagination or Media Count:

74.0

Abstract:

The report examines in detail the effects of electron, X-ray, and ultraviolet radiation on oxidized silicon surfaces and Planar devices. Two permanent surface effects of ionizing radiation are distinguished i The build-up of a positive space-charge within the oxide, and ii The creation of fast surface states at the oxide-silicon interface resulting in increased surface recombination velocity. The dependence of these effects on dose and dose rate, on bias applied during irradiation, and on structural parameters is discussed and a theory involving hole trapping is presented which accounts for the observed features of the space-charge build-up. Radiation-induced changes in the characteristics of MOS field-effect transistors, p-n junction diodes and pnp and npn transistors are reported and examined in terms of the above two effects. It is shown that the charge build-up causes shifts in the operating point of MOS transistors, catastrophic increases in the reverse current of p-n junctions, and large variation in their breakdown voltage. The increase in fast surface state density is responsible for the lowering of the transconductance of MOS transistors and, in combination with the space-charge build-up, for the degradation of the current gain in bipolar transistors. Author

Subject Categories:

  • Solid State Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE