| 摘要 |
PURPOSE:To form a silicate glass film having stable electric characteristics and small moisture absorptive property by reducing the pressure in a reaction tube of less than 5 Torr and setting the flow rate ratio oxygen in a range of 2.5- 5. CONSTITUTION:The pressure in a reaction tube is set to Torr, O2/SiH4 flow rate and O2/SiH4+PH3 flow rate are varied in a range of 1-6 to form an SiO2 film (a) and PSG film (b), these films are allowed to stand in steam of 2atms at 120 deg.C for 6 hours, and when the water content in the film is then measured, gas flow rate ratio is preferably 2.5-5, exhibiting nearly equal value to that by a normal pressure CVD method. No variation occurs in the threshold value of an MOS transistor having an SiO2 film and PSG film produced as above as surface protective films with the gas flow rate ratio of 2.5-5, thereby obtaining stable transistor. |
