| 摘要 |
PURPOSE:To form regions having different life times simultaneously by providing two oxide films of different thicknesses. CONSTITUTION:When a substrate 11 has been prepared, a thick thermal oxide film is formed on the main surface of the substrate 11, the thermal oxide film located on an island region 17 is removed by performing an etching leaving the thermal oxide film on island regions 16 and 18. Then, the above is heat-treated in the dry O2 atmosphere containing HCl, and a thermal oxide film is formed. A Cl ion dose not reach the interfaces of films 19a and 19c at the part where thick thermal oxide films 19a and 19c exist, and even when HCl is mixed in, almost no change in life time is observed. On the other hand, the effect of HCl mixture is appearing at the part where the thin thermal oxide film 19b exists, thereby enabling to increase the life time. After the thermal oxide film 19 has been formed as above, p and n layers are formed by selectively diffusing impurities. Ohmic contacts 20-27 are then formed and an IC is completed by connecting these contacts. |
