A method of forming a buried gate electrode prevents voids from being formed in a silicide layer of the gate electrode. The method begins by forming a trench in a semiconductor substrate, forming a conformal gate oxide layer on the semiconductor in which the trench has been formed, forming a first gate electrode layer on the gate oxide layer, forming a silicon layer on the first gate electrode layer to fill the trench. Then, a portion of the first gate electrode layer is removed to form a recess which exposed a portion of a lateral surface of the silicon layer. A metal layer is then formed on the semiconductor substrate including on the silicon layer. Next, the semiconductor substrate is annealed while the lateral surface of the silicon layer is exposed to form a metal silicide layer on the silicon layer.