High‐Aspect‐Ratio Parallel‐Plate Microchannels Applicable to Kinetic Analysis of Chemical Vapor Deposition

A method is proposed to fabricate a high‐aspect‐ratio (HAR) microchannel with a microscopic gap and AR of more than 1000:1 applicable to a test structure for kinetic analysis of chemical vapor deposition (CVD). It has a parallel‐plate structure and is formed concisely by sticking a planar Si substrate and a patterned Si or silicon‐on‐insulator (SOI) substrate fabricated by single‐step etching, by clamping them. The resulting feature exhibits a uniform gap and smooth surface morphology along its depth. When CVD is conducted into this HAR microchannel, the sticking probability ( η ) of film‐forming species can be detected by analyzing the film thickness gradient. The use of a microchannel with an AR of 1000:1 enables the elucidation of η values from 1 down to the order of 10 −7 . A kinetic analysis of SiC‐CVD from methyltrichlorosilane and H 2 is thus performed. It is found that conformal SiC‐film growth occurred inside the HAR microchannel, where one of the film‐forming species is revealed to have extremely low η around 10 −6 . The present study demonstrates that the developed HAR microchannel is a solution to access the overall reaction kinetics of CVDs, including film‐forming species with extremely low η .