Influence of conformal nitride material impacting the OTP & MTP data retention performance

Experimental condition of thin SAB Oxide around 350Aring coupling with 400Aring Contact SiON film has exhibited the worst data retention behavior in One Time Programmable (OTP) & Multiple Time Programmable (MTP) memory device. Another alternative solution has been explored to improve the data retention characteristic by replacing the 400Aring silicon oxynitride (SiON) contact stopper with 300Aring silicon nitride (SiN) material. A convincing results was demonstrated in the combination of 350Aring SAB Oxide with 300Aring Contact SiN film, although the combination of thicker SAB Oxide up to 1600Aring with 400Aring Contact SiON film is still feasible with the existence of some undesirable leakage behaviors inherited from SAB plasma dry etch process in OTP cell architecture. On the other hand, the MTP cell must use Contact SiN film as contact etch stopper to achieve the data retention performance due to array design architecture.