Parameters affecting the DC breakdown strength of parylene F thin films

The effect of some experimental parameters (electrode area, thickness, temperature and voltage rising rate) on the breakdown strength of films of poly(α,α, α',α'-tetrafluoro-p-xylylene), a fluorinated parylene (PA-F), has been studied. The measurements were performed in air on 20 capacitor structures for each condition and the two parameters of the Weibull distribution (α and β) were fitted to the data. The influences of electrode area (0.28, 4.5 and 18 mm2), film thickness (1.4, 5.0, 9.8, 21.5 and 49.4 μm), for a temperature range from 25°C to 350°C and voltage rising rate between 10 V/s and 100 V/s, have been investigated and discussed for the thinnest films. The thickness increases up to 5 μm leads to an increase in the dielectric strength with increasing the thickness whereas a continuous decrease is observed for higher thicknesses. Those results are correlated to the thickness dependent crystallinity of parylene films. The effect of electrode area, measured on the thinnest films, on the PA-F dielectric strength does not impact the Weibull parameters at 25 °C for high dielectric breakdown field values, whereas it induces a decrease in the β values at low field with increasing electrode area. This highlights the presence of randomly distributed defects in the tested structures. The temperature dependence of the dielectric strength was also investigated between 25°C and 350°C for two different thicknesses (1.4 and 5 μm) and shows negative temperature dependence in both cases. Finally, the effect of the rate of the applied field rising between 0.07 and 0.7 MV/cm.s on the thin films was studied at 25°C and 300°C and does not show any remarkable effect on the Weibull parameters.

[1]  G. C. Montanari,et al.  Weibull statistics in short-term dielectric breakdown of thin polyethylene films [comments and reply] , 1994 .

[2]  G. Damamme,et al.  Effect of the insulator size on the breakdown strength , 1997, IEEE 1997 Annual Report Conference on Electrical Insulation and Dielectric Phenomena.

[3]  J. J. O'Dwyer,et al.  The theory of electrical conduction and breakdown in solid dielectrics , 1973 .

[4]  P. Bjellheim,et al.  Electric breakdown strength of aromatic polymers: dependence on film thickness and chemical structure , 1991 .

[5]  John C. Fothergill,et al.  Estimating the cumulative probability of failure data points to be plotted on Weibull and other probability paper , 1990 .

[6]  M. Locatelli,et al.  Thickness dependence of the Maxwell-Wagner-Sillars dielectric relaxation dynamics in semicrystalline fluorinated parylene , 2011, 2011 - 14th International Symposium on Electrets.

[7]  G. Raju,et al.  DC breakdown characteristics of high temperature polymer films , 2006, IEEE Transactions on Dielectrics and Electrical Insulation.

[8]  M. Ieda,et al.  Dielectric Breakdown of Polyimide Film in High Temperature Region , 1976 .

[9]  Masayuki Ieda,et al.  Observation of Dielectric Breakdown Sites in Polyethylene Thin Film , 1980 .

[10]  Masayuki Ieda,et al.  Dielectric Breakdown Process of Polymers , 1980, IEEE Transactions on Electrical Insulation.

[11]  H. Zhou,et al.  Thickness dependent dielectric breakdown of PECVD low-k carbon doped silicon dioxide dielectric thin films: modeling and experiments , 2003, Microelectron. J..

[12]  W. Weibull.  A Statistical Distribution Function of Wide Applicability , 1951 .

[13]  Masayuki Ieda,et al.  Self-Healing Breakdown at Spherulite Boundaries of Polyethylene Thin Films , 1981 .

[14]  T. Schutte,et al.  DC breakdown strength of polypropylene films: area dependence and statistical behavior , 2007, IEEE Transactions on Dielectrics and Electrical Insulation.

[15]  Leonard A. Dissado.  Theoretical basis for the statistics of dielectric breakdown , 1990 .

[16]  Masayuki Hikita,et al.  Dielectric breakdown and electrical conduction of poly(vinylidene-fluoride) in high temperature region , 1980 .

[17]  W. F. Gorham,et al.  Preparation and reactions of some [2.2] paracyclophane derivatives , 1969 .

[18]  Miss A.O. Penney.  (b) , 1974, The New Yale Book of Quotations.

[19]  F. Shi,et al.  Temperature accelerated dielectric breakdown of PECVD low-k carbon doped silicon dioxide dielectric thin films , 2005 .