Fabrication of Nanoscale Step Height Structure Using Atomic Layer Deposition Combined with Wet Etching

The current techniques used for the fabrication of nanosteps are normally done by layer growth and then ion beam thinning. There are also extra films grown on the step surfaces in order to reduce the roughness. So the whole process is time consuming. In this paper, a nanoscale step height structure is fabricated by atomic layer deposition （ALD） and wet etching techniques. According to the traceable of the step height value, the fabrication process is controllable. Because ALD technology can grow a variety of materials, aluminum oxide （Al2O3） is used to fabricate the nanostep. There are three steps of Al2O3 in this structure including 8 nm, 18 nm and 44 inn. The thickness of Al2O3 film and the height of the step are measured by anellipsometer. The experimental results show that the thickness of Al2O3 film is consistent with the height of the step. The height of the step is measured by AFM. The measurement results show that the height is related to the number of cycles of ALD and the wet etching time. The bottom and the sidewall surface roughness are related to the wet etching time. The step height is calibrated by Physikaliseh-Technische Bundesanstalt （PTB） and the results were 7.5±1.5 nm, 15.5±2.0 nm and 41.8±2.1 nm, respectively. This research provides a method for the fabrication of step height at nanoscale and the nanostep fabricated is potential used for standard references.

亚50 nm台阶高度标准物质的可控制备及定值研究

纳米台阶高度标准物质可以传递准确、可溯源的纳米高度量值。针对我国缺乏可控的高质量亚50 nm台阶高度标准物质制备技术的问题,提出了基于原子层沉积结合湿法刻蚀的纳米台阶高度标准物质研制方法,通过工艺过程优化实现了台阶高度亚纳米量级精确可控,制备出了最小公称高度仅为5 nm的亚50 nm台阶高度标准物质系列。其定值结果可溯源到米定义波长基准,扩展不确定度不超过2.0 nm,均匀性和稳定性较好,不同测试仪器一致性水平较高。研究结果表明,所研制的纳米台阶高度标准物质可以用于亚50 nm高度量值传递以及多种测量仪器之间量值的比对测量,其产业化批量生产的前景也将为半导体产业提供完善的计量保障。