220 into a reaction chamber and maintaining a low pressure of about 6 5 torr while simultaneously exposing the conductor layer pattern 220 to a phosphine ph 3 gas at a temperature between 600 u00b0 c to 700 u00b0 c preferably 650 u00b0 c for a time duration of about 120 minutes step 130 in another embodiment the phosphorous doping of the hsg formed polysilicon layer 220 is performed under a ph 3 gas pressure of about 200 torr at a temperature in the range of about 620 u00b0 c to 680 u00b0 c for a time duration of 120 minutes after doping of the composite polysilicon pattern layer including the hsg layer 230 and polysilicon pattern layer 220 a diffusion barrier layer 240 is formed on the hsg layer 230 at step 140 here a nitrogen gas is provided to react with the surface of the hsg layer 230 to form a silicon nitrite layer 240 the nitration process may be performed at a temperature between 600 u00b0 c and 700 u00b0 c preferably 650 u00b0 c for a duration of 180 minutes following the formation of the silicon nitride layer 240 a dielectric layer 250 is formed on the silicon nitride layer in an embodiment the dielectric layer comprises a high dielectric material such as aluminum oxide al 2 o 3 tantalum oxide ta 2 o 5 having a thickness about 45 u00e5 at step 160.