几种基于MEMS的纳米梁制作方法研究

Studies on Several Methods of Fabrication of Nano-Beams Based on MEMS

特征尺度在纳米量级的梁结构是多种纳机电器件的基本结构.提出了几种基于MEMS技术的纳米梁制作方法,通过利用MEMS技术中材料与工艺的特性实现单晶硅纳米梁的制作.在普通(111)硅片上,利用各向异性湿法腐蚀对(111)面腐蚀速率极低的特性,通过干法与湿法腐蚀相结合制成厚度在100nm以下的纳米梁.该方法不使用SOI硅片,有效控制了成本.在(100)SOI硅片上,通过氧化减薄的方法得到厚度在100nm以下的多种纳米梁,由于热氧化的精度高,一致性好,该方法重复性与一致性均较好.在(110)SOI硅片上,利用硅的各向异性腐蚀特性以及(110)硅片的晶向特点,制作宽度在100nm以下的纳米梁,梁的两个侧面是(111)面.

Nano-bearn is the basic structure of the device used in NEMS. Several methods to fabricate the singlecrystalline silicon nano-bearns are presented. These methods take advantage of the characteristic of material and process in MEMS technology. The cantilever and the double clamped beams whose thickness is lower than 100 nm can be fabricated in （111） wafers by combining the anisotropic wet etching with the drying etching. Compared with the methods based on the SOI wafers, the method is low cost as the expensive SOI wafers are not needed. As the bottom surfaces of the nano-beams are （111） plane, the etching is self-stopped after the nano beams are formed. Therefore, the thickness of the beams can be controlled accurately. Several nano-bearn structures whose thickness is less than 100 nm can be fabricated in （100） SOl silicon wafers by reducing the thickness of the top layer silicon with thermal oxidation. The consistency and the repeatability of the method are good because the thermal oxidation has good precision and repeatability. The two clamped beams whose width is less than 100 nm can be fabricated in （110）SOI silicon wafers by using the anisotropic wet etching.