Abstract Single-crystal silicon carbide (SiC) has gained tremendous attention for harsh-environment sensor applications due to its high-temperature tolerance and chemical resistance. However, there are many technological challenges in the fabrication of single-crystal SiC sensing microstructures such as thin SiC diaphragms for pressure sensors. This paper presents an ultrasonic vibration mill-grinding (UVMG) technique for the fabrication of 6H-SiC sensor diaphragms. The fundamental machining characteristics of UVMG are investigated experimentally compared with conventional mill-grinding (CMG). The experimental results show that the axial grinding force in UVMG is reduced by 60–70% compared to that in CMG. In addition, the wheel loading is severe in CMG, while the issue of wheel loading is significantly alleviated in UVMG due to the discontinuous cutting characteristic achieved in this method. As a result, sharp increase of the axial grinding force, which is accompanied by the crack of SiC workpiece, happens frequently in CMG after a total grinding depth of 200 µm. By contrast, the axial grinding force is stable in UVMG during the total grinding depth of at least 900 µm. The ultrasonic vibration in UVMG results in rough surface finish due to the material-removal mechanism of brittle fracture. However, by taking the advantages of better machining stability in UVMG and better surface roughness in CMG, extremely thin SiC sensor diaphragms with satisfactory surface quality can be achieved. Finally, we demonstrate the successful fabrication of a thin SiC diaphragm with a thickness of 20.3 µm.

中文翻译：

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用于压力传感器膜片的单晶碳化硅的超声波振动研磨研磨

摘要 单晶碳化硅 (SiC) 因其耐高温和耐化学性而在恶劣环境传感器应用中受到极大关注。然而，在制造单晶 SiC 传感微结构（例如用于压力传感器的薄 SiC 隔膜）方面存在许多技术挑战。本文介绍了一种用于制造 6H-SiC 传感器膜片的超声波振动研磨 (UVMG) 技术。将 UVMG 的基本加工特性与传统的铣削 (CMG) 进行了比较实验研究。实验结果表明，与CMG相比，UVMG的轴向磨削力降低了60-70%。另外，CMG的轮载很严重，而在 UVMG 中，由于该方法实现了不连续的切割特性，车轮载荷问题得到了显着缓解。因此，在 CMG 中，在总磨削深度为 200 µm 后，轴向磨削力急剧增加，并伴随着 SiC 工件的裂纹。相比之下，在 UVMG 中轴向磨削力在至少 900 µm 的总磨削深度期间是稳定的。由于脆性断裂的材料去除机制，UVMG 中的超声波振动导致粗糙的表面光洁度。然而，通过利用 UVMG 更好的加工稳定性和 CMG 更好的表面粗糙度的优势，可以获得具有令人满意的表面质量的极薄 SiC 传感器膜片。最后，我们展示了厚度为 20.3 µm 的薄 SiC 隔膜的成功制造。