Method for fabricating a self-aligned stacked capacitor of semiconductor device

PURPOSE: A method for forming a self-aligned stack capacitor of a semiconductor device is provided to obtain a sufficient capacitance in a high-integrated device. CONSTITUTION: In the method, the first oxide layer(3) is formed on a silicon substrate(1), and an undoped polysilicon layer(4) is formed thereon. Next, the undoped polysilicon layer(4) is patterned to a desired contact hole size, and the second oxide layer is formed thereon. Then, the second oxide layer and the first oxide layer(3) are dry-etched to the silicon substrate(1) to form a self-aligned contact hole. Thereafter, a doped polysilicon layer(7) is deposited and dry-etched to form a sidewall on respective sides of the second oxide layer and the contact hole. Next, a lower electrode(8) made of refractory metal or silicide thereof is formed on exposed surfaces, and the remaining second oxide layer is removed. Then, a dielectric layer(9) of Ta2O5 and an upper electrode(10) of refractory metal or silicide thereof are formed in sequence over a resultant structure.