Anisotropic wet etching is a most widely employed for the fabrication of MEMS/NEMS structures using silicon bulk micromachining. The use of Si{110} in MEMS is inevitable when a microstructure with vertical sidewall is to be fabricated using wet anisotropic etching. In most commonly employed etchants (i.e. TMAH and KOH), potassium hydroxide (KOH) exhibits higher etch rate and provides improved anisotropy between Si{111} and Si{110} planes. In the manufacturing company, high etch rate is demanded to increase the productivity that eventually reduces the cost of end product. In order to modify the etching characteristics of KOH for the micromachining of Si{110}, we have investigated the effect of hydroxylamine (NH2OH) in 20 wt% KOH solution. The concentration of NH2OH is varied from 0 to 20% and the etching is carried out at 75 °C. The etching characteristics which are studied in this work includes the etch rates of Si{110} and silicon dioxide, etched surface morphology, and undercutting at convex corners. The etch rate of Si{110} in 20 wt% KOH + 15% NH2OH solution is measured to be four times more than that of pure 20 wt% KOH. Moreover, the addition of NH2OH increases the undercutting at convex corners and enhances the etch selectivity between Si and SiO2.

中文翻译：

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Si {110}在20 wt％KOH中加入羟胺的刻蚀特性，用于制造批量微机械MEMS

各向异性湿法蚀刻是使用硅体微机械加工制造MEMS / NEMS结构最广泛使用的方法。当要使用湿法各向异性蚀刻制造具有垂直侧壁的微结构时，在MEMS中不可避免地使用Si {110}。在最常用的蚀刻剂（即TMAH和KOH）中，氢氧化钾（KOH）表现出较高的蚀刻速率，并改善了Si {111}和Si {110}平面之间的各向异性。在制造公司中，要求高蚀刻速率以提高生产率，最终降低最终产品的成本。为了修改用于Si {110}的微加工的KOH的蚀刻特性，我们研究了20 wt％KOH溶液中羟胺（NH2OH）的作用。NH 2 OH的浓度在0至20％之间变化，并且蚀刻在75℃下进行。在这项工作中研究的蚀刻特性包括Si {110}和二氧化硅的蚀刻速率，蚀刻的表面形态以及凸角处的底切。经测量，Si {110}在20 wt％KOH + 15％NH2OH溶液中的蚀刻速率是纯20 wt％KOH的蚀刻速率的四倍。而且，NH 2 OH的添加增加了凸角处的底切并增强了Si和SiO 2之间的蚀刻选择性。