Obtaining a high area ratio free-standing silicon microchannel plate via a modified electrochemical procedure

A silicon microchannel plate (Si MCP) is of large interest for electron multiplication. Conventional fabrication processes utilize an etching process on the front side and wafer thinning on the backside. In this note, a process based on electrochemical etching, developed to generate a gap between the device layer and the substrate, is presented. A sample containing a microchannel through-hole structure can be directly obtained with a laser cut by scanning the laser beam on the surface without cutting through the wafer. An oxidation step is used to increase the MCP's electrical resistance. After dry oxidation at 900 °C, structure distortion is observed in the free-standing sample. Thus, oxidizing before cutting the microchannel plate from the substrate is recommended.