| 摘要 |
PURPOSE:To contrive formation of a highly microscopic semiconductor by a method wherein the width of a groove is reduced by forming a well isolating groove by performing a self-alignment. CONSTITUTION:The first oxide film 102 is formed on a P-type semiconductor substrate 101, a nitride film 103 is formed on the side wall of the oxide film 102, N-type impurities 104 are ion-implanted using said films as a mask, and the second oxide film 105 is selectively formed by performing a thermal oxidization method. After the nitride film 103 has been removed using thermal phosphoric acid, a well isolation groove 106 is formed by performing an active-ion etching on a part of the semiconductor substrate 101 using the oxide films 102 and 105 as a mask. Then, after the third oxide film 107 has been formed inside the groove 106 using an oxidizing method, a polycrystalline silicon 108 is formed on the whole surface by performing a chemical vapor growth method, and the polycrystalline silicon 108 on the outside of the groove 106 is removed by performing an etching back operation. Then, an N-well 109 is formed by performing a drive-in process at 1000-1100 deg.C.
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