| 摘要 |
PURPOSE:To stabilize the characteristic of a semiconductor device by a method wherein the single layer of a CVD oxide film and a resist layer applied on the top surface thereof are utilized together as a mask. CONSTITUTION:A gate oxide film 2 and a field oxide film 3 are formed on an N type silicon substrate 1, and a poly-silicon layer 4 containing N type impurities is deposited thereon. A CVD oxide film 5 is adhered, and the CVD oxide film is removed excluding a region containing a gate formation programing region using photolithography technique. The poly-silicon layer 4 and the gate oxide film 2 are etched to be removed leaving a resist film 6 as it is. Boron is introduced into layers 7 according to the ion implantation method using the layer consisting of the CVD oxide film 5 and the resist film 6 in the gate region and the field oxide film 3 as a mask. Probability to be implanted with boron in the CVD oxide film 5 and the poly-silicon gate layer 4, and to receive damage is reduced, and stability of the threshold voltage is enhanced. |
