Polarity asymmetry of oxides grown on polycrystalline silicon

The quality of oxide thermally grown on polycrystalline silicon, commonly referred to as polyoxide, is strongly dependent on polysilicon doping processes and polyoxide growth conditions. The electrical properties of polyoxides using different polysilicon doping processes (in situ, ion implanted, and POCl/sub 3/) and different oxidation processes (dry, wet, and LPCVD) have been studied. The emphasis is on the dependence of the polarity asymmetry of leakage current, critical electric field histogram, electron trapping rate, and charge to breakdown. Polyoxides with in situ doped polysilicon exhibit an unusual polarity asymmetry, i.e. higher field enhancement and charge to breakdown are observed when the upper electrode is biased negative. This is the opposite of the asymmetry reported for polyoxides before. High-temperature annealing of the polysilicon films prior to oxidation reduces this asymmetry. >

[1]  Chenming Hu,et al.  Electron trapping in very thin thermal silicon dioxides , 1981, 1981 International Electron Devices Meeting.

[2]  T. T. Sheng,et al.  Electrical conduction and breakdown in oxides of polycrystalline silicon and their correlation with interface texture , 1982 .

[3]  D. Dimaria,et al.  Interface effects and high conductivity in oxides grown from polycrystalline silicon , 1975 .

[4]  Ih-Chin Chen,et al.  Electrical breakdown in thin gate and tunneling oxides , 1985 .

[5]  H. R. Huff,et al.  Experimental Observations on Conduction Through Polysilicon Oxide , 1980 .

[6]  E. Irene,et al.  Silicon Oxidation Studies: Morphological Aspects of the Oxidation of Polycrystalline Silicon , 1980 .

[7]  S.K. Lai,et al.  Comparison and trends in today's dominant E2technologies , 1986, 1986 International Electron Devices Meeting.

[8]  Joshua Alspector,et al.  Properties of Thermal Oxides Grown on Phosphorus In Situ Doped Polysilicon , 1983 .

[9]  M. Liang,et al.  Charge Trapping in Dielectrics Grown on Polycrystalline Silicon , 1989 .

[10]  D. Kerr,et al.  Evidence for surface asperity mechanism of conductivity in oxide grown on polycrystalline silicon , 1977 .

[11]  L. Faraone,et al.  Characterization of thermally oxidized n+polycrystalline silicon , 1985, IEEE Transactions on Electron Devices.

[12]  S. Mori,et al.  Reliable CVD Inter-Poly Dielectrics for Advanced E&EEPROM , 1985, 1985 Symposium on VLSI Technology. Digest of Technical Papers.

[13]  K. Shinada,et al.  Low Leakage Current Polysilicon Oxide Grown by Two-Step Oxidation , 1985, 23rd International Reliability Physics Symposium.