1. Materials Science and Engineering, University of California San Diego, La Jolla, California 92093, United States
2. Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
3. Taiwan Semiconductor Manufacturing Corporation (TSMC), Hsinchu 300-78, Taiwan
4. Irvine Materials Research Institute, University of California Irvine, Irvine, California 92697, United States
5. Material Science and Engineering, University of Texas, Dallas, Texas 75080-3021, United States