摘要 |
A cryogenic radiation-hard dual-layer field oxide of reoxidized nitrided oxide (ONO) which provides radiation hardness for field-effect transistors and other semiconductor devices at cryogenic temperatures. The dual-layer field oxide includes a thin lower dielectric layer of reoxidized nitrided oxide and an upper deposited dielectric layer that remains charge neutral. The upper dielectric layer is preferably silicon nitride or a doped oxide, such as phospho silicate glass or boro phospho silicate glass. The lower dielectric layer can be made very thin since reoxidized nitrided oxide is a much better barrier layer to the diffusion of boron or phosphorous from the upper dielectric layer into the silicon substrate than silicon dioxide. A thin lower dielectric layer allows only a small amount of positive charge buildup, while the upper dielectric layer traps both holes and electrons and remains charge neutral.
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