e a high chamber polymer is not good the higher polymer condition taper profile is generated easily as opposed to the desired vertical profile polysilicon layer 12 may be patterned using for example patterned masking layer 14 as a mask as shown in fig2 as shown in fig2 as polysilicon layer 12 is etched to formed etched polysilicon layer 12 u2032 passivation ions i e those ions that would form polymer on the film layer 12 surface to generate vertical profile are implanted into the polysilicon layer 12 as at 20 to form a passivation layer portion 18 within etched polysilicon layer 12 u2032 the passivation ions are preferably c 2 f 6 c 4 f 8 or cf 4 and are more preferably c 2 f 6 passivation layer portion 18 has a passivation ion concentration of preferably from about 100 to 100 000 atoms cm 3 and more preferably from about 1000 to 10 000 atoms cm 3 and is from about 100 to 1000 u00e5 thick and is more preferably from about 300 to 800 u00e5 thick passivation layer portion 18 extends preferably from about 100 to 1000 u00e5 and more preferably from about 300 to 800 u00e5 beneath the upper surface 19 of the patterned polysilicon layer 12 u2032 this passivation of polysilicon layer 12 during the c 2 f 6 etch process 16 achieves a vertical profile of etched polysilicon layer 12 u2032 as shown in fig2 and 3 as shown in fig3 any patterned masking layer 14 is.