| 摘要 |
PURPOSE:To obtain desired threshold-value voltage by applying an energy beam to a gate region after the MOS-type semiconductor device is prepared and thereby reducing surface change caused by the defect of a gate oxidized film and a substrate. CONSTITUTION:A thick field SiO2 film 2 is formed in the peripheral part of the P<-> type Si substrate 1 and further a thin SiO2 film 4 and a polycrystalline Si film 3 containing N type impurities are laminated on the substrate 1 surrounded by the film 2 and are connected thereto. Next, the laminate is turned into a gate electrode 3 by patterning through the intermediary of the gate SiO2 film 4, and by using the electrode 3 as a mask, source and drain regions 5 and 6 on N<+> side are formed diffusely within the substrate 1 on both sides of the mask. After that, the whole surface is covered with an SiO2 film 7, contact holes are made in respective regions, and electrodes 9-11 are fitted to each region of the gate source and drain. Then, a laser beam is applied to the gate regions in a forming gas containing 90% N2 and 10% H2 and thus the threshold-value voltage is controlled without incurring any pollution. |
