Specimens for quality transmission electron microscopy (TEM) analyses must fulfil a range of requirements, which demand high precision during the prior preparation process. In this work, an optimized procedure for conventional TEM specimen preparation is presented that exploits the thickness-dependence of interference colors occurring in birefringent materials. It facilitates the correct estimation of specimen thickness to avoid damage or breaking during mechanical thinning and reduces ion-milling times below 30 min. The benefits of the approach are shown on sapphire and silicon carbide cross-section samples. The presented method is equally suitable for assessing specimen thickness during dimpling and wedge-polishing, and is particularly useful at thicknesses below 20 µm, where the accuracy of mechanical techniques is insufficient. It is precise enough to be employed for a visual thickness estimation during the thinning process, but can be additionally optimized by analyzing the RGB spectrum of the occurring interference colors.

用于高质量透射电子显微镜 (TEM) 分析的样品必须满足一系列要求，这些要求在之前的制备过程中需要高精度。在这项工作中，提出了一种传统 TEM 样品制备的优化程序，该程序利用了双折射材料中干涉色的厚度依赖性。它有助于正确估计样品厚度，以避免机械减薄过程中的损坏或断裂，并将离子铣削时间减少到 30 分钟以下。该方法的优点在蓝宝石和碳化硅横截面样品上得到了体现。所提出的方法同样适用于评估压凹和楔形抛光过程中的样品厚度，并且在机械技术精度不足的厚度低于 20 µm 的情况下特别有用。它足够精确，可用于细化过程中的视觉厚度估计，但还可以通过分析出现的干涉色的 RGB 光谱进行额外优化。