Abstract: The present invention is related to a method for forming nanometer-sized silicon quantum dots. The method includes the steps of: forming a silicon nitride thin film using active and low energy nitrogen ions on a silicon substrate; forming a uniform silicon thin film on the silicon nitride thin film by a silicon vapor deposition technique; forming silicon nitride islands by injecting a nitrogen gas; forming silicon quantum dots covered with the silicon nitride islands by etching silicon thin film, not covered with the silicon nitride thin film, by injecting an oxygen gas; eliminating the silicon nitride thin film covering the silicon quantum dots by using reactive ions.