METHODS OF MANUFACTURING SEMICONDUCTOR DEVICES WITH LOCAL RECESS CHANNEL TRANSISTORS

摘要

A method of manufacturing a local recess channel transistor in a semiconductor device. A hard mask layer is formed on a semiconductor substrate that exposes a portion of the substrate. The exposed portion of the substrate is etched using the hard mask layer as an etch mask to form a recess trench. A trench spacer is formed on the substrate along a portion of sidewalls of the recess trench. The substrate along a lower portion of the recess trench is exposed after the trench spacer is formed. The exposed portion of the substrate along the lower portion of the recess trench is doped with a channel impurity to form a local channel impurity doped region surrounding the lower portion of the recess trench. A portion of the local channel impurity doped region surrounding the lower portion of the recess trench is doped with a Vth adjusting impurity to form a Vth adjusting impurity doped region inside the local channel impurity doped region. The width of the lower portion of the recess trench is expanded. A gate insulating layer is formed on the substrate in the recess trench. A gate electrode layer is formed on the gate insulating layer in the recess trench. A portion of the gate insulating layer and the gate electrode layer is etched to form a gate.