Nanohole texturing to improve the performance of a microscopic photodetector

Nano-texturing technology has received significant attention as the demand for the miniaturization of optical devices grows. In this paper, we report the fabrication process and formation mechanisms for textured nanoholes on a silicon substrate developed using a Cl2-based high-density plasma system to improve the performance of microscopic optical devices. The mechanisms underlying the formation of the nanoholes were determined based on the results derived from variations in the etching time and conditions for the injected gas, while the effect of the plasma on the nanohole structure was evaluated in relation to changes to the upper and lower radio frequency (RF) power. The aspect ratio of the nanoholes ranged from 0.100 to 0.796 depending on the upper/lower RF power, while it was confirmed that the surface reflectance of the silicon substrate decreased and the performance of the metal-semiconductor-metal photodetector improved as the density of the nanoholes increased. These results are expected to contribute to improving the performance of optical devices.