The present invention discloses a method for forming a semiconductor device with a reduced silicon horn structure. After a pad nitride layer is removed from a substrate, a hard mask layer is conformally deposited over the substrate. The hard mask layer is then etched and trimmed to completely remove a portion of the hard mask layer from an active area and a portion of the hard mask layer from an oblique sidewall of a protruding portion of a trench isolation region around the active area. The active area is then etched to form a recessed region. A gate dielectric layer is formed in the recessed region and a gate electrode layer is formed on the gate dielectric layer.