| 摘要 |
PURPOSE:To lessen a change of conductance by a method wherein when an Al gate self-matching MOS transistor is prepared, B<+> ions are injected into the substrate about the gate electrode and a region with high layer resistance is formed by applying a laser beam to that part. CONSTITUTION:The N-type Si substrate 21 is coated with SiO2 film, the gate SiO2 film 23 is left between the source and drain regions 24, 25 to be formed, the protective SiO2 film 22 is left on other part, and B impurity is diffused into the substrate to form the P-type regions 24, 25. Next Al film is applied to the entire surface of the substrate, and is patterned to form the source electrode 26, drain electrode 27 and gate electrode 28. B<+> ions are injected into the substrate about the electrode 28 by using those electrodes as masks to form a shallow ion-injected layer 29. After this, a Q-switch ruby laser beam 30 is applied to the layer 29 to anneal it, and a high resistance of 3kOMEGA/cm<2> is provided to the layer. In this way, a change of conductance can be controlled within a range of + or -2% even with a large current operation for a long time. |
