Sulfur Implanted Black Silicon for Metal Semiconductor Metal (MSM) Photodetectors.

摘要

We have investigated a wet chemical process for nanoscale texturing of sulfur-doped silicon (Si) surfaces, which results in substantial suppression of the reflectivity in a broad spectral range, leading to black Si surfaces. The blackened surface was characterized optically and with Veeco micro- profiler. We fabricated metal semiconductor metal (MSM) test devices using the aforementioned black silicon and electrically characterized them for current- voltage (I-V), optical response, zero biased quantum efficiency (QE), and optical responsivity. We observe increased optical response and responsivity for the blackened silicon. One key observation we have made is the extension of the detectivity up to 1.2 m, which is beyond 1.1 m for a typical silicon detector. This observation was made under zero bias to the detector. We conclude that anneling and metal enhanced chemical etching (MECE) treatment prior to fabrication of the devices have enhanced the detectivity of the devices beyond the typical bandgap of 1.1 m of silicon.