Improvement in the Electrical Properties in n-ZTO/p-SiC Heterojunction Structures via Post-Annealing

We studied the effect of the post-annealing process on the electrical properties of an n-ZTO/p-SiC (4H-SiC) heterojunction. Heterojunctions with a Zinc-Tin oxide (ZTO) active layer were fabricated via solution processing, and after post-annealing, the I-DS (@V-GS similar to 5V) increases from similar to 18.56x10(-6)A to similar to 5.52x10(-3) A, and the threshold voltage (VTH) shifted to the negative bias direction. As a result, thermally activated carriers are generated and the density of oxygen vacancies in the ZTO film decrease, as confirmed by the 1/C-2 characteristics and FTIR spectroscopy. The 1/C2 results shows that the post-annealing process depletes the width, and the built-in voltage and carrier concentration improve in the n-ZTO/p-SiC heterostructure. After post-annealing, we confirmed that the built-in voltage and carrier concentration increased to similar to 2.41V and 6.12x10(20) cm(-3) according to the changes in depletion width and resistivity.