Roughening and destructive effects of sintering on micron-sized ZnO features

Microfabrication of ceramic features has become a critical issue in realizing the miniaturization of devices. Micron-sized ZnO features attract much attention because of their unique properties of direct wide bandgap, high exciton binding energy, good piezoelectrics, and easy doping for devices. However, limited effort has been devoted to understanding the sintering behaviors of micron-sized ZnO features. In this study, micron-sized ZnO ridges were prepared via centrifuge-aided micromolding and sintered at 950 °C for different time in air atmosphere. The sintering process destructs the ZnO ridges via abnormal grain growth and surface roughening. The relationship difference in grain growth vs. densification between the bulk and the features is elucidated, and gas evaporation during sintering is the major contributor to grain growth. Destruction prediction of ridge features using sintering time and bulk relative density is established based on grain growth and densification. Feature surface roughening is further analyzed with respect to thermodynamic fundamentals.

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