Gamma Irradiation Effects on 4H-SiC MOS Capacitors and MOSFETs


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The effects of gamma radiation on field effect mobility and threshold voltage have been studied for lateral n-channel 4H-SiC MOSFETs passivated with nitric oxide. MOS capacitors (n and p) and n-channel lateral MOSFETs were irradiated unbiased (floating contacts) for a total gamma dose of 6.8Mrad (Si). The MOS capacitors were used to study the radiation-induced interface traps and fixed oxide charge that affect the performance of the MOSFETs. Radiationinduced interface traps were observed near the SiC valence band edge and just above mid-gap, and field effect channel mobility was reduced by 18-20% following irradiation. Even so, 4HMOSFETs appear to be more radiation tolerant than Si devices.



Materials Science Forum (Volumes 527-529)

Edited by:

Robert P. Devaty, David J. Larkin and Stephen E. Saddow




A. C. Ahyi et al., "Gamma Irradiation Effects on 4H-SiC MOS Capacitors and MOSFETs", Materials Science Forum, Vols. 527-529, pp. 1063-1066, 2006

Online since:

October 2006




[1] T. Ohshima, H. Itoh and M. Yoshikawa: J. Appl. Phys. Vol. 90 (2001), p.3038.

[2] K.K. Lee, T. Ohshima and H. Itoh: IEEE Trans. Nucl. Sci. Vol. 50 (2003), p.194.

[3] G.Y. Chung, et al.: IEEE Elect. Dev. Lett. Vol. 22 (2001), p.176.

[4] P.J. McWhorter and P.S. Winokur: Appl. Phys. Lett. Vol. 48 (1986), p.133.

[5] J.R. Brews: Applied Solid State Science, D. Kahhny, editor, (Academic Press, New York, 1981), p.31.

[6] F.W. Sexton and J.R. Schwank: IEEE Trans. Nucl. Sci. Vol. 32 (1985), p.3975. Fig. 4. Mobility vs VGS and IDS-VGS characteristics for n-channel 4H-SiC MOSFETs before and after 6. 8Mrad gamma rays.