Techiques for forming a silicon quantum dot, which can be applied to the formation of a semiconductor memory device, are disclosed. The techniques may include depositing a first dielectric layer on a semiconductor substrate, depositing a polysilicon layer on the first dielectric layer, forming a plurality of metal clusters on the polysilicon layer in regular distance, and etching the polysilicon layer using the plurality of metal clusters as a mask. As disclosed herein, it is possible to form the silicon quantum dots having the fineness and uniformity characteristic together with the single crystalline level characteristic.