A method of forming a hardened nano-imprinting stamp is disclosed. The hardened nano-imprinting stamp includes a plurality of silicon-based nano-sized features that have an hardened shell of silicon carbide, silicon nitride, or silicon carbide nitride. The hardened shell is made harder than the underlying silicon by a plasma carburization and/or a plasma nitridation process. During the plasma process atoms of carbon and/or nitrogen bombard and penetrate a plurality of exposed surfaces of the nano-sized features and chemically react with the silicon to form the hardened shell of silicon carbide, silicon nitride, or silicon carbide nitride.