| 摘要 |
PURPOSE:To localize a floating gate electrode on a channel between source and drain regions, by forming floating gate electrode in self-aligning manner together with a control gate electrode at the end parts of the source and drain regions and in a self- aligning manner together with element isolating grooves at the end parts of a channel. CONSTITUTION:On a P-type semiconductor substrate 1, a first oxide film 2, which is to become a first gate oxide film 2A, is formed by thermal oxidation. Then, a first polycrystalline silicon film 3, which is going to become a floating gate electrode 3A, is grown by an ordinary vapor phase growing method. Phosphorus, which is N-P type impurities, is added. Then, a second oxide film 4 is formed on the first polycrystalline silicon film 3 by thermal oxidation. Thereafter a second polycrystalline silicon film 5 is grown. Then the first oxide film 2, the first polycrystalline silicon film 3, the second oxide film 4 and the second polycrystalline silicon film 5, which are on a region that is to become an element isolating region, are removed. The exposed surface of the semiconductor substrate 1 is etched, and element isolating grooves 6 are formed. Then photoresist is removed. By the grooves 6, the floating gate electrode 3A is formed in a self-aligning manner. |
