METHOD FOR FABRICATING SEMICONDUCTOR DEVICE WITH BULB TYPE RECESS GATE

摘要

A method for manufacturing a semiconductor device having a bulb-type recess gate is provided to prevent diffusion of a boron dopant due to heat generated from a subsequent space dielectric forming process by forming a thermal diffusion layer through a plasma nitridation process. A plasma nitridation process is performed on an upper portion of a semiconductor substrate(11) to form a thermal diffusion barrier. A hard mask pattern for opening a recess forming region is formed on an upper portion of the nitrided substrate. A predetermined thickness of the substrate is etched by using the hard mask pattern as an etching mask to form a first recess. A cell channel ion implantation process is performed to form a channel ion implantation region(19). A spacer dielectric(20) is formed on the whole surface of the resultant structure including the first recess. The spacer dielectric is wholly etched and the substrate of the lower portion of the exposed first recess is etched to form a globe-shaped second recess. A gate pattern is formed on a recess comprised of the first recess and the second recess.