dc.description.abstract | With the development of the optoelectronic industry, when the performance reaches a certain bottleneck, the appearance of the passivation layer greatly improves the performance of the optoelectronic components. However, there is no passivation layer between the metal and the semiconductor, some research teams have studied to complete the passivation by means of local opening. However, the opening of the hole will cause serious carrier recombination, therefore the technique of passivating contact will come into being. The thin film is the key to passivation contact. When the single-layer passivated contact film is developed to a certain level, the structure of the single layer cannot meet the requirements of the component, so the passivation contact film of the compound film is proposed. The composite passivation contact film has better passivation effect than the single-layer passivation contact, so this study applied it to the photodetector and studied its component characteristics.
In this study, we use wet chemical oxidation method to grow silicon oxide film, and we try the different parameters of wet chemical oxidation method to find the best silicon oxide film with the highest density and low leakage current. Then silicon nitride film is deposited on the silicon oxide film to achieve the effect of compound film of passivation contact. After rapid thermal annealing treatment, it is found that the compound film has the best passivation effect at 500 °C, with the highest lifetime of 1021.25μs and iVoc of 652.4mV. Then we will fabricate the devices of different silicon nitride thickness and measure their electrical properties.
Finally, the compound film of passivation contact is applied to the silicon-based photodetector. Indium tin oxide was deposited on compound films for improving the responsibility. The results show that when the compound film of passivation contact is made by using silicon oxide 1.5nm of thickness and silicon nitride 1.7nm, it has the best passivation effect, and the dark current of the photodetector can be reduced from 4.36x10-7A to 8.25x10-9A, photon responsibility of 0.582 A/W at a laser light source of 850 nm.
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