MOSFET having a highly doped channel liner and a dopant seal to provide enhanced device properties

摘要

A fabrication process and integrated circuit are provided in which a transistor having increased resistance to punchthrough and decreased channel capacitance is formed. A liner layer is formed within the active region of a transistor to minimize punchthrough. A barrier layer is then formed between the liner layer and the upper surface of the semiconductor substrate. The barrier layer preferably inhibits migration of the liner ions into the junction and channel regions of the transistors during subsequent processing steps. Such migration could deleteriously affect transistor function by, e.g., increasing the threshold voltage and thus decreasing the drive current. The barrier layer also preferably facilitates formation of shallow junctions. In an embodiment, the liner layer may include p-type ions such as boron and the barrier layer may include nitrogen implanted into the semiconductor substrate. Alternatively, the barrier layer may include nitrogen-incorporated epitaxially grown silicon.