| 摘要 |
PURPOSE:To improve reliability by burying low resistance polyscrytalline silicon in a contact hole. CONSTITUTION:An insulation layer 2 PSG and a corrosion resistance layer 4 silicon nitride layer are coated by turns on an N-type silicon substrate 1 using vapor phase growth. Then, a contact hole is formed by patterning, a polycrystalline silicon layer 5 is coated to make the surface of the substrate smooth covering the contact hole, a phosphorus ion is implanted and the polycrystalline silicon layer 5 is made low resistance. Then, the polycrystalline silicon layer 5 is oxidized to the depth of an oxidation resistance layer 4 at 1,100 deg.C using wet O2 and a silicon oxide layer 6 is formed. In this case, the polycrystalline silicon layer 5 remains in the contact hole. The silicon oxide layer 6 is removed by etching and Al is coated as a wiring layer 3 covering the polycrystalline silicon layer 5 in the contact hole. This enables to improve reliability improving a step cover without increasing contact resistance. |
