Negative charge induced degradation of PMOSFETs with BF2-implanted p+-poly gate

A new degradation phenomenon on thin gate oxide PMOSFETs with BF₂ implanted p⁺-poly gate has been demonstrated and investigated. The cause of this type of degradation is a combination of the boron penetration through the gate oxide and charge trap generation due to the presence of fluorine in the gate oxide and some other processing-induced effects. The negative charge-induced degradation other than enhanced boron diffusion is studied in detail here. The impact of this process-sensitive p⁺-poly gate structure on deep submicron CMOS process integration has been discussed.