原子层沉积钌/氧化铝复合纳米薄膜的制备与电阻调控

Fabrication and Bulk Resistance Modulation of Ru/Al_(2)O_(3)Composite Nanofilm by Atomic Layer Deposition

目的针对目前微通道板(MCP)导电层电阻可调范围窄、性能稳定性差等问题,提出一种新的MCP导电层的制备方法。方法应用原子层沉积(ALD)工艺在硅片上沉积不同厚度的Al_(2)O_(3)和Ru薄膜,以获得较优的纳米薄膜制备工艺参数,应用扫描电子显微镜(SEM)得到薄膜的截面厚度及成膜质量,应用能量色散X射线光谱(EDS)表征了薄膜的元素组成。基于获得的优选工艺参数,在MCP基板上应用ALD工艺交替沉积Al_(2)O_(3)和Ru 2种材料,并且改变Ru与Al_(2)O_(3)的ALD循环比例,制备了一系列Ru/Al_(2)O_(3)复合纳米薄膜作为MCP导电层。对制备的一系列MCP导电层进行体电阻测试,并在不同偏压下进行体电阻稳定性测试。结果由SEM与EDS结果可知,利用ALD制备的Al_(2)O_(3)和Ru纳米薄膜成膜特性良好,且薄膜沉积速率稳定。对于镀覆于MCP内表面的Ru/Al_(2)O_(3)导电层,体电阻测试结果显示,随着复合薄膜中Ru的ALD循环次数增加,MCP体电阻明显降低,适用于MCP导电层制备的工艺参数为:Ru的ALD循环数为28~40,Al_(2)O_(3)的ALD循环数为10。在导电层制备过程中延长吹扫时间并在烘烤后随炉冷却,MCP导电层体电阻在不同偏压下具有良好的稳定性。结论利用ALD制备Ru/Al_(2)O_(3)复合纳米薄膜作为MCP导电层,实现了体电阻从几至几百兆欧的调控,工艺优化后的导电层体电阻具有良好的稳定性,对扩展导电层可选材料范围,提升MCP器件性能具有工程应用价值。

Applying atomic layer deposition(ALD)technology to fabricate the functional layer of a microchannel plate(MCP)has been verified to be an effective approach to enhancing MCP performance.However,the conduction layer inside the MCP device faces the issues of a narrow range of adjustable resistance and poor stability.The work aims to propose a method of utilizing ALD to fabricate Ru/Al_(2)O_(3)composite nanofilm as the MCP conduction layer since Al_(2)O_(3)has good environmental stability and excellent dielectricity and Ru possesses the properties of excellent thermal stability and high-temperature corrosion resistance.In order to explore the process parameters,Al_(2)O_(3)and Ru nanofilms were deposited on Si wafers by ALD technology with different ALD cycle numbers.The cross-section thickness of the nanofilms was obtained by scanning electron microscopy(SEM),and the relative elemental composition of the nanofilms was obtained by energy-dispersive X-ray spectroscopy(EDS).The SEM characterization showed that applying ALD technology for the deposition of nanofilm resulted in high film quality,compact layer structure,and dense atomic arrangement.Moreover,the film thickness showed only a slight deviation from the estimated thickness,and the selected process parameters met the expected experimental objectives.On this basis,the Ru/Al_(2)O_(3)composite nanofilm was fabricated by depositing two materials sequentially with ALD technology.A series of Ru/Al_(2)O_(3)composite films were fabricated by maintaining a constant number of ALD cycles for Al_(2)O_(3)and varying the ALD cycles for Ru,aiming to control the bulk resistance of the conduction layer.The bulk resistance of the MCP conduction layers was tested,and the stability of the bulk resistance was tested under different bias voltages.From the SEM and EDS results,it could be concluded that the process of preparing Al_(2)O_(3)and Ru nanofilms with ALD was stable.The bulk resistance significantly decreased with the increase of ALD cycles of Ru according to the bulk resistance test results.The process parameters applicable to the preparation of the MCP conduction layer were Ru with an ALD cycle number of 28~40 and Al_(2)O_(3)with an ALD cycle number of 10.In this case,the MCP bulk resistance was controlled in the range from 709 to 3.98 MΩ.The MCP bulk resistance was then tested under different bias voltages,namely,post-deposition without/with baking and extending purge time during deposition followed by natural cooling.The MCP bulk resistance showed preferable stability under different bias voltages by employing the process of extending purge time followed by natural cooling.With ALD technology,controlling the MCP bulk resistance from several to several hundred megohms has been achieved.Moreover,the optimized process for the conduction layer exhibits excellent stability regarding MCP bulk resistance.This work holds engineering application value in extending the range of conduction layer materials,and also makes significant sense for improving MCP performance.