Characterization of MOS Capacitors Fabricated on n-type 4H-SiC Implanted with Nitrogen at High Dose

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Aiming to minimize the interface state density, we fabricated MOS capacitors on n-type 4H-SiC by using wet oxidation of nitrogen implanted layers. We investigated a wide range of implantation dose, including a high dose able to amorphise a surface SiC layer with the intent to reduce the oxidation time. The oxide quality and the SiO2-SiC interface properties were characterized by capacitance-voltage measurements of the MOS capacitors. The proposed process, in which nitrogen is ion-implanted on SiC layer before a wet oxidation, is effective to reduce the density of interface states near the conduction band edge if a high concentration of nitrogen is introduced at the SiO2-SiC interface. We found that only the nitrogen implanted at the oxide-SiC interface reduces the interface states and we did not observe the generation of fixed positive charges in the oxide as a consequence of nitrogen implantation. Furthermore, the concentration of the slow traps evaluated from the Slow Trap Profiling technique was low and did not depend on the nitrogen implantation fluence.

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Periodical:

Materials Science Forum (Volumes 556-557)

Edited by:

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

Pages:

639-642

Citation:

A. Poggi et al., "Characterization of MOS Capacitors Fabricated on n-type 4H-SiC Implanted with Nitrogen at High Dose", Materials Science Forum, Vols. 556-557, pp. 639-642, 2007

Online since:

September 2007

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$38.00

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[8] S. Dimitrijev, P. Tanner and H.B. Harrison: Microelectronics Reliability Vol. 39 (1999), p.441 � Ninte r Ntotal Neff (cm -2) Dit at 0. 3 eV / 0. 6 eV (eV-1cm -2) TDst (cm -2) #1 low low -2. 6�10.

[11] 2. 6�10.

[12] / 1. 8�10.

[11] 2. 7x10.

[10] #2 high low <10.

[10] 4�10.

[11] / 2. 7�10.

[11] 5. 0x10.

[10] #3 low high -3. 5�10.

[11] 2. 2�10.

[12] / 2. 2�10.

[11] 3. 7x10.

[10] #4 high high <1010 4�10.

[11] / 1. 7�10.

[11] 2. 1x10.

[10] Table 2 N concentration at the oxide-SiC interface Ninter, total amount of N inside the oxide film Ntotal, effective oxide charges density Neff, , interface state density Dit at 0. 3 and at 0. 6 eV, and total density of the slow traps TDst for all of the samples.

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