| 摘要 |
PURPOSE:To bring an active region to a non-defect condition at the same time by heating a semiconductor substrate in an oxidizing atmosphere and heating it repeatedly up to a predetermined temperature at the prescribed rate of a temperature rise when a gate oxide film is formed to the surface of the substrate exposed through etching. CONSTITUTION:An SiO2 film 3 and an Si3N4 film 4 are laminated and coated onto the active region of a P<-> type Si substrate 1, and a thick field oxide film 5 is shaped around the laminated films through heating in wetted oxygen. The laminated films are removed through reactive-ion etching using CF4 gas containing 5-10% O2, but a crystal defect layer 6 having high density is formed in the active region 2 through the impulse of ions and radicals at that time. Accordingly, when the gate oxide film 7 is shaped onto the layer 6, the film 7 is formed through heating at 1,100 deg.C in O2 containing 5% HCl, the substrate is cooled down to 650-800 deg.C, the gas is changed over to N2 gas, and heating is repeated only by desired number up to 1,100 deg.C at the rate of the temperature rise of 2-10 deg.C/min. |
