A model relating wearout to breakdown in thin oxides

A model has been developed relating wearout to breakdown in thin oxides. Wearout has been described in terms of trap generation inside of the oxide during high voltage stressing prior to breakdown. Breakdown occurred locally when the local density of traps exceeded a critical value and the product of the electric field and the higher leakage currents through the traps exceeded a critical energy density. The measurement techniques needed for determining the density of high-voltage stress generated traps have been described along with the method for coupling the wearout measurements to breakdown distributions. The average trap density immediately prior to breakdown was measured to be of the order of low-10/sup 19//cm/sup 3/ in 10 nm thick oxides fabricated on p-type substrates stressed with negative gate voltages. The model has been used to describe several effects observed during measurements of time-dependent-dielectric-breakdown distributions. The area dependence of breakdown distributions, the differences in the breakdown distributions during constant current and constant voltage stressing, and the multi-modal distributions often observed were simulated using the model. The model contained the provision for incorporation of weak spots in the oxide. >

[1]  R. S. Scott,et al.  A statistical model of oxide breakdown based on a physical description of wearout , 1992, 1992 International Technical Digest on Electron Devices Meeting.

[2]  T. R. Oldham,et al.  Spatial Dependence of Trapped Holes Determined from Tunneling Analysis and Measured Annealing , 1986, IEEE Transactions on Nuclear Science.

[3]  E. Harari.  Dielectric breakdown in electrically stressed thin films of thermal SiO2 , 1978 .

[4]  D. Dumin,et al.  Transient Flat-Band Voltage Shifts Following High Voltage Stressing of Thin Oxides , 1992 .

[5]  E. E. King,et al.  Improved method for evaluating hot-carrier aging in p-channel MOSFET's , 1993, 31st Annual Proceedings Reliability Physics 1993.

[6]  Jordi Suñé,et al.  Degradation and Breakdown of Gate Oxides in VLSI Devices , 1989, February 16.

[7]  D. Arnold,et al.  Impact ionization, trap creation, degradation, and breakdown in silicon dioxide films on silicon , 1993 .

[8]  D. Kwong,et al.  Influence of process parameters on the time‐dependent dielectric breakdown of rapid thermally nitrided and reoxidized nitrided thin SiO2 , 1992 .

[9]  E. Harari,et al.  Conduction and trapping of electrons in highly stressed ultrathin films of thermal SiO2 , 1977 .

[10]  R. S. Scott,et al.  A model relating wearout induced physical changes in thin oxides to the statistical description of breakdown , 1993, 31st Annual Proceedings Reliability Physics 1993.

[11]  Y. Hokari,et al.  Stress voltage polarity dependence of thermally grown thin gate oxide wearout , 1988 .

[12]  A. Brand,et al.  Novel read disturb failure mechanism induced by FLASH cycling , 1993, 31st Annual Proceedings Reliability Physics 1993.

[13]  B. Riccò,et al.  High-field-induced degradation in ultra-thin SiO/sub 2/ films , 1988 .

[14]  N. Shiono,et al.  A lifetime projection method using series model and acceleration factors for TDDB failures of thin gate oxides , 1993, 31st Annual Proceedings Reliability Physics 1993.

[15]  George A. Brown,et al.  The polarity, field and fluence dependence of interface trap generation in thin silicon oxide , 1992 .

[16]  D. Dumin,et al.  Measurement of High Voltage Stress Induced Traps Inside Thin Silicon Oxide Films , 1992 .

[17]  R. S. Scott,et al.  Voltage, Fluence, and Polarity Dependence of Trap Generation Inside of Thin Silicon Oxide Films * , 1992 .

[18]  M. Wada,et al.  Stress induced leakage current limiting to scale down EEPROM tunnel oxide thickness , 1988, Technical Digest., International Electron Devices Meeting.

[19]  C. K. Williams.  Kinetics of trapping, detrapping, and trap generation , 1992 .

[20]  C. Hu,et al.  Stress-induced current in thin silicon dioxide films , 1992, 1992 International Technical Digest on Electron Devices Meeting.

[21]  George A. Brown,et al.  Polarity dependence of thin oxide wearout , 1989 .

[22]  B. Ricco,et al.  Influence of localized latent defects on electrical breakdown of thin insulators , 1991 .

[23]  D. J. Dumin,et al.  Correlation of stress-induced leakage current in thin oxides with trap generation inside the oxides , 1993 .

[24]  C. Hu,et al.  Hole injection oxide breakdown model for very low voltage lifetime extrapolation , 1993, 31st Annual Proceedings Reliability Physics 1993.

[25]  Jordi Suñé,et al.  On the breakdown statistics of very thin SiO2 films , 1990 .

[26]  Jack C. Lee,et al.  Modeling and characterization of gate oxide reliability , 1988 .

[27]  R.-P. Vollertsen,et al.  Dependence of dielectric time to breakdown distributions on test structure area , 1990, Proceedings of the 1991 International Conference on Microelectronic Test Structures.

[28]  C. Hu,et al.  Stress-induced oxide leakage , 1991, IEEE Electron Device Letters.

[29]  Eduard A. Cartier,et al.  Degradation and breakdown of silicon dioxide films on silicon , 1992 .