Electrical Properties of Ultra Thin Multilayer Dielectrics on Polysilicon

We demonstrate the feasibility of very thin ONO (SiO
2
/Si
3
N
4
/SiO
2
) dielectrics on poly-Si for 16M DRAM application. For D
ox eff.
= 8.5nm, the leakage current density is lower than 10
^-8
A/cm
²
, and the long term stability is more than 10 years at electric fields of 5.5MV/cm. The onset of tunneling current in ONO dielectrics depends on the thickness of the SiO
2
entry potential barrier. The high field current characteristic depends on the thickness of the SiO
2
exit potential barrier.