| 摘要 |
PURPOSE:To obtain a semiconductor device having an LDD structure without danger of causing device characteristics based on the irregularity of a frame size to vary in an extremely simple step of merely utilizing a side etching at the time of forming a gate insulating film, a gate electrode. CONSTITUTION:A thermal oxide film is first formed on the main surface of a silicon semiconductor substrate 1, a polycrystalline silicon film containing phosphorus in high concentration is deposited, a resist pattern 7 for forming a gate electrode is patterned by a photoresist working technique, sidewisely etched to desired degree by plasma etching, and a gate insulating film 2 and a gate electrode 3 are selectively formed with an HF etchant. A desired overetch is performed after so-called just etching in the step of etching the film 2 and the electrode 3, a desired undercutting amount 9 is set by controlling the sidewisely etching amount, thereby obtaining an object device configuration, i.e., a desired LDD structure.
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