| 摘要 |
PURPOSE:To remove a natural oxide film on a silicon substrate and obtain an extremely thin silicon oxide film of quality and uniformity, by consitituting a semicondutor manufacturing equipment including a furnace tube and a boat made of siliconcarbide or silicon. CONSTITUTION:It is required to remove a natural SiO2 film which has already been piled up on an MNOS-structured Si substrate 1, when an extremely thin SiO2 film of 20-30Angstrom thick is formed on the substrate 1. When the natural SiO2 film is removed by reduction in an H2 atmosphere at 1,050-1,250 deg.C., a blur 2 appears to the substrate 1 close to a boat 4 upstream. As a furnace tube 3 and a boat 4 is made of quartz, the quartz is etched and becomes an SiO2 film as the same way as the natural SiO2 film on the substrate 1. It sticks to the substrate 1 and a deficiency like pitted shape occurs. Therefore, both furnace tube 3 and boat 4 are made of SiC or Si to avoid it. |
