| 摘要 |
PURPOSE:To improve the stabilization in the threshold voltage and properties of an FET by using a high melting point metal for a gate electrode, and interposing an Si3N4 film between the metal film and a resist mask in case of forming the electrode. CONSTITUTION:A field oxidized film 2 and a gate oxidized film 3 are formed on a P type Si substrate 1, an Mo film 4 and an Si3N4 film 5 are superposed by a CVD method, a resist mask 6 is coated, the films 5, 4 are etched by reactive ion etching or plasma ashing to form a gate electrode 4a. Then, As ions are implanted to form N<+> type layers 7a, 7b, and the film 5 is removed. A PSG film 8 is covered, heat-treated to decrease the resistance of the film 4, and to activate the layers 7a, 7b, and aluminum electrodes 9 are attached. According to this structure, gate wiring resistance can be reduced, and the introduction of Na of the Si3N4 from the resist mask to the Mo film can be effectively prevented. The Mo film prevents the ion implantation in the gate electrode, and the PSG getters mobile ions of the gate insulating film. Thus, the threshold can be determined with good controllability, thereby obtaining stable element properties. |
