A Study on Cryo-Electrochemistry to Fabricate Nanocrystals on Si Substrate

In this study, the low temperature porous silicon electrochemical etching study carried out since 2017 has been carried out. Preliminary experimental results show that the free carrier absorption has a considerable influence on the electrochemical etching. In 2017, the research team found that the infrared laser radiation suppresses the etching with the free-carrier absorption effect. Therefore, we further selected the laser with infrared wavelength of 1310-1550 nm and lowered the ambient temperature of the etching bath to minus 74 ° C Feasibility of formation of sub-nanocrystalline (~ 0.5 nm) by dual-suppression etching with free-carrier-loading effect and low temperature effect. Preliminary experimental results show that the long-wavelength laser irradiation can inhibit the etching, since the laser shine point, there are wavy narrow pattern generated outside, is expected to have a breakthrough discovery, in photoluminescence measured with UV light excitation, and There is no general porous silicon photoluminescence phenomenon, the wavelength of the light to stimulate the assessment may not be in the range of light, which assumes the need for further research and analysis. This project continues the 2017 study, not only analyzing its activation energy, deriving the relationship between the etching rate and the photoactivation activation energy, but also studying the relevant literature and expecting to propose a model of uniform distribution of porous silicon distribution by the inhibition mechanism , Proposed a deep well-like structure that explains how electrochemical etching makes a homogeneous surface of the silicon crystal (so far not yet accepted as accepted). In addition to the theoretical study, there are practical industrial applications: the control development of the etching rate through the laser power can replace the fabrication of some components in MEMS, the photoresist coating and the removal of light in the development process Blocking steps. This technology to shorten the manufacturing process and reduce costs, to achieve the production of 3D driver components, but also look forward to the silicon photonic integrated core device material production technology to make some revolutionary breakthroughs.