WALL-INDUCED EFFECTS IN GAS-TRANSPORT THROUGH MICROMACHINED CHANNELS IN SILICON

It has recently been shown that micromachined channels can be used to study gas transport at Knudsen-like conditions also close to atmospheric pressures. The channels are etched into a silicon surface and covered by a glass lid through anodic bonding. An unexpected pressure dependence of diffusion lag times through channels around 100 nm deep and a few centimeters long is concentrated on. A simple tentative model, based on the adsorption of gas molecules onto the channel walls, is resented which can explain an observed decrease in lag time with pressure and an influence of one species on the diffusion lag time of another species in a gas mixture. Some observations on chemical reactions on modified channel walls are also discussed.