1. Shaanxi Province Key Laboratory for Electrical Materials and Infiltration TechnologySchool of Materials Science and EngineeringXi’an University of Technology Xi’an 710048 P. R. China
2. Xi’an Microelectronic Technology Institute Xi’an 710065 P. R. China
3. Institute of Materials ScienceTechnische Universität DarmstadtFB Nichtmetallisch‐Anorganische Werkstoffe Alarich‐Weiss‐Straße 2 Darmstadt D‐64287 Germany