| 摘要 |
PURPOSE: A formation method of an isolation layer is provided to prevent an electrical attenuation and residues of a gate electrode by forming 'L'-type spacer nitrides and adequate-sized bird's beaks beneath the 'L'-type spacer nitrides. CONSTITUTION: After forming a pad thermal oxide(15) and a pad nitride(20) on a semiconductor substrate(10), and etching the pad nitride(20) to form an isolation layer, a thermal oxide and a nitride are sequentially deposited. Spacer oxides(30') and spacer nitrides(25') are formed by selectively etching the thermal oxide and the nitride. After completely removing the spacer oxides(30') to form 'L'-type spacer nitrides(25'), a field thermal oxide(35) is formed with bird's beaks, thereby preventing a formation of a moat when forming an isolation layer. Then, a trench is formed using the pad nitride(20) as a mask.
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