Unified model of damage annealing in CMOS, from freeze-in to transient annealing

Conference · Mon Dec 01 04:00:00 EST 1975 · IEEE Trans. Nucl. Sci., v. NS-22, no. 6, pp. 2157-2162

OSTI ID:4087913

Sander, H H; Gregory, B L

Irradiation studies at 76$sup 0$K are described which demonstrate that radiation-produced holes in SiO$sub 2$ are immobile at this temperature. If an electric field of either polarity is present in the SiO$sub 2$ during 76$sup 0$K irradiation, to sweep out the mobile electrons, the holes will virtually all be trapped where created and produce a uniform positive charge density in the oxide. This predicts $delta$V/sub T/ varies as d/sub ox/$sup 2$, which is observed. The magnitude of the observed shift is consistent with 18 eV required per hole- electron pair generated. All CMOS transistors of the same oxide thickness exhibit the same initial $delta$V/sub T/, for a given exposure level, regardless of oxide type or process. The rate of annealing differs, both as a function of oxidation process and oxide thickness. Thin oxides have two advantages: a smaller $delta$V/sub T/ (stable shift) and faster annealing. If a CMOS device is irradiated for sufficient time at 76$sup 0$K to build in an appreciable field, further irradiation with zero gate-substrate bias will produce little additional change in V/sub T/, since the field in the oxide tends to keep all generated electrons in the oxide, where they recombine with trapped holes. Room temperature annealing following a pulsed gamma exposure occurs in two regimes. The first regime can be quite fast, and occurs prior to 10$sup -4$ seconds. The magnitude of this early-time recovery is both process dependent and thickness dependent. In a hardened device most of the damage anneals during this early- time stage, whereas in a typical non-hardened unit the early-time stage (recovery) can be quite small. (auth)

• Research Organization: Sandia Labs., Albuquerque, NM
• NSA Number: NSA-33-020341
• OSTI ID: 4087913
• Conference Information: Journal Name: IEEE Trans. Nucl. Sci., v. NS-22, no. 6, pp. 2157-2162
• Country of Publication: United States
• Language: English

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