Development of high purity one ATM ozone source - Its application to ultratuin SiO₂ film formation on Si substrate

A high-concentration ozone generator operating at atmospheric pressure has been developed for fabrication of ultra thin silicon oxide films. The generator can supply atmospheric pressure of ozone jet with ozone concentration up to 80 vol%. The ozone jet is generated by desorbing ozone at nearby room temperature, which has been condensed on silica-gel by passing ozone/oxygen mixture gas from a commercial ozonizer at a low temperature (<-50°C); at the temperature ozone is more selectively adsorbed on silica-gel than oxygen. The high purity ozone jet with a concentration of 25 vol% at a pressure of l x 105 Pa had so large oxidation power that SiCh film as thick as 3.3 nm grew on a Si surface after GO min exposure at 375°C. The density of the film was equivalent to that of the film formed by a conventional thermal oxidation process, judging from etching rate with dilute HF solution.