| 摘要 |
PURPOSE: An ion implantation method for realizing a desired dopant concentration is provided to be capable of controlling final MOSFET threshold voltage value by selecting the adequate line-width. CONSTITUTION: A substrate(200) underlies an epitaxially grown p- layer(202). Mask elements(204,206,208,210) are placed over the epitaxial layer(202) and phosphorous or arsenic dopant ions are implanted into the epitaxial layer(202) in the open spaces between the mask elements(204,206,208,210). A layer of photoresist, silicon nitride, silicon dioxide or other material that is partially transmissive to the ions to be implanted through the mask element is formed over the epitaxial layer(202). A mask element having a plurality of different-width lines is created, and the mask is used to pattern the layer such that a line is located proximate each of n-type wells. |
