KY(WO₄)₂ is a promising material for on-chip laser sources. Deep etching of small KY(WO₄)₂ samples in combination with various thin film deposition techniques is desirable for the manufacturing of such devices. There are, however, several difficulties that need to be overcome before deep etching of KY(WO₄)₂ can be realized in small samples in a reproducible manner. In this paper, we address the problems of (i) edge bead formation when using thick resist on small samples, (ii) sample damage during lithography mask touchdown, (iii) resist reticulation during prolonged argon-based inductively coupled plasma reactive ion etching (ICP-RIE), and (iv) redeposited material on the feature sidewalls. We demonstrate the etching of 6.5 µm deep features and the removal of redeposited material using a wet etch procedure. This process will enable the realization of waveguides both in ion-irradiated KY(WO₄)₂ as well as thin KY(WO₄)₂ membranes transferred onto glass substrate by bonding and subsequent polishing.

中文翻译：

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小KY（WO4）2样品中无重沉积的深蚀刻

KY（WO ₄）₂是用于片上激光源的有前途的材料。结合各种薄膜沉积技术对小KY（WO ₄）₂样品进行深度蚀刻对于制造此类器件是理想的。但是，在深腐蚀KY（WO ₄）₂之前，需要克服一些困难。可以以可重现的方式在小样本中实现。在本文中，我们解决了以下问题：（i）在小样品上使用厚抗蚀剂时形成边缘珠粒;（ii）光刻掩模触地时样品损坏;（iii）长时间基于氩的感应耦合等离子体反应离子刻蚀时的抗蚀剂网状化（ ICP-RIE），以及（iv）在特征侧壁上重新沉积材料。我们演示了对6.5 µm深特征的蚀刻以及使用湿法蚀刻工艺去除再沉积材料的方法。该过程将使得能够在离子辐照的KY（WO ₄）₂以及通过粘结和随后的抛光转移到玻璃基板上的KY（WO ₄）₂薄膜中实现波导。