Acceleration Factors in Acceleration Life Test of Thermal Oxides on 4H-SiC Wafers


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Acceleration factors in acceleration life test of thermal oxides grown on 4H-SiC(0001) wafers and influences of dislocations on oxide reliability have been investigated using time-dependent dielectric breakdown measurements. The thermal oxides are formed by dry oxidation at 1200°C followed by annealing in nitrogen atmosphere. Then, post oxidation annealing in wet ambient at 950°C or hydrogen atmosphere at 800°C were carried out for some of the oxides. Aluminum or poly-Si films with thickness of 300 nm were formed as gate electrodes. The temperature dependence of time-to-breakdown (tBD) indicates that activation energy (Ea) values for the Al-gate and Poly-Si-gate thermal oxides are 0.59 eV - 0.79 eV and 0.34 eV - 0.72 eV, respectively. Analyzing the electric field dependence of tBD, it was indicated that the values of electric acceleration parameters (β) are 2.7 cm/MV - 7.0 cm/MV and 5.8 cm/MV - 7.1 cm/MV for the Al-gate and poly-Si-gate thermal oxides, respectively. In addition, the charge-to-breakdown decreases with increase in the density of basal plane dislocation.



Materials Science Forum (Volumes 556-557)

Edited by:

N. Wright, C.M. Johnson, K. Vassilevski, I. Nikitina and A. Horsfall




J. Senzaki et al., "Acceleration Factors in Acceleration Life Test of Thermal Oxides on 4H-SiC Wafers", Materials Science Forum, Vols. 556-557, pp. 635-638, 2007

Online since:

September 2007




[1] K. Yamabe and K. Taniguchi: IEEE Trans. Electron Devices. Vol. 32 (1985), p.423.

[2] C.F. Chen, C.Y. Wu, M.K. Lee and C.N. Chen: IEEE Trans. Electron Devices. Vol. 34 (1987), p.1540.

[3] K.C. Chang, H.T. Nuhfer, L.M. Porter and Q. Wahab: Appl. Phys. Lett. Vol 77 (2000), p.2186.

[4] V.V. Afanas'ev, A. Stesmans and C.I. Harris: Mater. Sci. Forum Vol. 264-268 (1998), p.857.

[5] V.V. Afanas'ev, A. Stesmans, M. Bassler, G. Pensl and M.J. Schulz: Appl. Phys. Lett. Vol. 76 (2000), p.336.

[6] N.S. Saks, S.S. Mani and A.K. Agarwal: Appl. Phys. Lett. Vol. 76 (2000), p.2250.

[7] J. Senzaki, K. Kojima, T. Kato, A. Shimozato and K. Fukuda: Appl. Phys. Lett. Vol. 89 (2006), 022909.

[8] C.Y. Chang and S.M. Sze: ULSI Technology (The McGRAW-HILL Companies, INC., 1996). 0. 001 0. 01 0. 1 1 10 1. E+02 1. E+03 1. E+04 1. E+05 Density of BPD [/cm2] Charge to breakdown [C/cm 2] Fig. 4. Correlation between charge-to- breakdown and density of basal plane dislocations under the TDDB condition that electric field and temperature are normalized to 9 MV/cm and 20°C.