Effect of nitrogen annealing on SiC/SiO 2 interface properties was comparatively investigated for SiC MOS capacitors. Interface properties were characterized by normalized parallel conductance and interface state den...
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ISBN:
(纸本)9781509026142
Effect of nitrogen annealing on SiC/SiO 2 interface properties was comparatively investigated for SiC MOS capacitors. Interface properties were characterized by normalized parallel conductance and interface state density value, anddielectric strength was evaluated by the electric-field-to-breakdown (Ebd). The results exhibited that both fast and slow states were present at the nitrogen-annealed samples' parallel conductance characteristics. Thus, we could conclude that nitrogen annealing led to incomplete nitridation of SiC/SiO 2 interface. Based on the results, nitridation mechanism was simply analyzed. It seemed that the nitridation process started from near conduction band, extending till to mid-band-gap. Besides, when the samples underwent higher temperature nitrogen annealing, more slow states were converted into fast ones, indicating that higher annealing temperature could lead to more effective nitridation. It was suggested that nitrogen annealing resulted in incomplete nitridation of SiC/SiO 2 interface regardless of oxide thickness and that this process was limited to the annealing temperature. The higher the annealing temperature was, the more effective the nitridation effects were.
Ti/Al contacts deposited on p-type epilayerdoped with Al at 2×10 19 cm -3 are reported. The current-voltage curves of Ti/Al contacts annealed at different temperatures from 800 to 1000 °C were measured, w...
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Ti/Al contacts deposited on p-type epilayerdoped with Al at 2×10 19 cm -3 are reported. The current-voltage curves of Ti/Al contacts annealed at different temperatures from 800 to 1000 °C were measured, which provided the specific contact resistances (SCrs) of 6.59×10 -5 Ω/cm 2 and 7.81×10 -5 Ω/cm 2 after annealing at 900°C for 5min and 950°C for 2min, respectively. The microstructures of Ti/Al contact on P-type 4H-SiC were investigated by X-ray diffraction (Xrd). The results of Xrd show that the phases of Ti 3 SiC 2 was formed at the metal/SiC interface after annealing, which could be effective to ohmic contacts on P-type 4H-SiC. The quantitative phase analysis were also discussed, which show that the phase composition of Ti 3 SiC 2 is key factor for low resistance to P-type 4H-SiC. Moreover, simulations proved that the gradual Ti 3 SiC 2 ISL reduces or eliminates the effective barrier height at the metal/Ti 3 SiC 2 /p-type and may also contribute to low contact resistivity.
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