Abstract Microstructural evolution of Au thin film in post-annealing by microwave and by electric furnace heating was compared. Wave number spectra of film surface roughness were analyzed to characterize their roughness variation by annealing. Coarsening of film microstructure occurred consistently as the increase of the annealing temperature in both methods. Labyrinth-shaped morphologies consisting of bump-ridge crystals were formed by annealing, which might be originated from the fine-grained colonies existed in the as-deposited state. Through coalescence and growth of the grains within the colony, the bump-ridge crystals increased their height as the increase of annealing temperature. Eventually, microstructures and crystal morphologies became similar by both annealing methods above 800–850 °C. However, there are following differences observed in the low temperature annealing cases: 1. While a temporal variation of the film microstructure was observed in furnace annealing, microwave annealing exhibited smaller tendency of this feature. 2. Fine roughness (higher wave number range) of the films was reduced more in the temperature below 720 °C by microwave annealing than by furnace annealing. 3. Increase of bump-ridge height was pronounced more by microwave annealing between 600 and 800 °C, corresponding to the roughness increase in the lower wave number range. On the other hand, film coverage decreased. The reasons for the difference was discussed by consideration of the competition among the capillary driven surface diffusion, contribution of electro-migration and the thermodynamic equilibrium shapes of the film grain structures.

中文翻译：

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微波和电炉加热快速退火中金薄膜的表面粗糙度变化和微观结构演变

摘要 比较了微波和电炉加热后退火Au薄膜的显微组织演变。分析薄膜表面粗糙度的波数谱，以通过退火表征其粗糙度变化。在两种方法中，随着退火温度的增加，薄膜微观结构的粗化一致发生。通过退火形成由凸脊晶体组成的迷宫形形态，这可能源于沉积状态中存在的细粒菌落。通过菌落内晶粒的聚结和生长，随着退火温度的升高，凸脊晶体的高度增加。最终，通过高于 800-850 °C 的两种退火方法，微观结构和晶体形态变得相似。然而，在低温退火的情况下观察到以下差异： 1. 虽然在炉退火中观察到薄膜微观结构的时间变化，但微波退火表现出较小的趋势。2. 与炉退火相比，微波退火在低于 720 °C 的温度下降低了薄膜的精细粗糙度（更高的波数范围）。3. 在 600 到 800 °C 之间进行微波退火，凸块脊高度的增加更加明显，对应于较低波数范围内的粗糙度增加。另一方面，薄膜覆盖率下降。通过考虑毛细管驱动的表面扩散、电迁移的贡献和薄膜晶粒结构的热力学平衡形状之间的竞争，讨论了差异的原因。