Rj. Milanowski et al., COMBINED EFFECT OF X-IRRADIATION AND FORMING GAS ANNEAL ON THE HOT-CARRIER RESPONSE OF MOS OXIDES, IEEE transactions on nuclear science, 40(6), 1993, pp. 1360-1366
Process-radiation-induced defects and hot-carrier instability in n-cha
nnel transistors subjected to simulated X-ray lithography have been st
udied. Using optically-assisted electron injection (photoinjection), t
wo specific instability mechanisms were investigated: (1) trapping of
electrons at coulombic centers in the bulk oxide and (2) depassivation
/passivation of interface traps by hydrogen originating in the bulk ox
ide. Devices treated with a standard forming gas anneal after X-irradi
ation show residual, but minor, susceptibility to hot-carrier-induced
instability via both these mechanisms. These results can be explained
by the presence of post-anneal neutral electron traps and the failure
of the forming gas anneal to fully restore the pre-irradiation hydroge
n-transport properties of the oxide.