Patterning sub-30-nm MOSFET gate with i-line lithography

We have investigated two process techniques: resist ashing and oxide hard mask trimming. A combination of ashing and trimming produces sub-30-nm MOSFET gate. These techniques require neither specific equipment nor materials, These can be used to fabricate experimental devices with line width beyond the limit of optical lithography or high-throughput e-beam lithography. They provide 25-nm gate pattern with i-line lithography and sub-20-nm pattern with e-beam lithography, A 40-nm gate channel length nMOSFET is demonstrated.