| 摘要 |
<p>A method for forming a semiconductor device is provided to reduce the change of a threshold voltage of the semiconductor device and to prevent a leakage current by performing an oxygen ion implantation process to form a recess region for a bulb of a bulb-type recess region in advance. An isolation layer for defining an active region(120) is formed on a semiconductor substrate(100). A hard mask layer pattern(145) for exposing a gate expectation region is formed on the semiconductor substrate. An oxygen ion implantation process is performed by using the hard mask layer pattern as an ion implantation mask to form an oxide layer(160) in a predetermined depth of a lower portion of the gate expectation region. A spacer is formed on a sidewall of the hard mask layer pattern. The active region is etched by using the hard mask layer pattern and the spacer as an etch barrier until the oxide layer is exposed. The exposed oxide layer is removed to form a bulb-type recess region on the active region. After the hard mask layer pattern and the spacer are removed, a gate is formed to gap-fill the bulb-type recess region.</p> |
