Particle Precipitation in Connection with KOH Etching of Silicon
Particle Precipitation in Connection with KOH Etching of Silicon
复制标题
与 KOH 硅蚀刻相关的颗粒沉淀
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
E. Thomsen
中科院分区：
文献类型：
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作者：
C. Nielsen;C. Christensen;C. Pedersen;E. Thomsen
本文研究了硅片中氧化铁颗粒的析出与氢氧化钾腐蚀空腔的关系。本文的研究结果表明，这些颗粒的来源是用于制造蚀刻液的KOH颗粒。实验表明，沉淀与KOH刻蚀时间无关，但沉积物质的量随掺杂类型和掺杂浓度的不同而不同。实验还表明，沉淀发生在硅片从KOH腐蚀液中去除时，而不是在腐蚀过程中。当不去除时，氧化铁颗粒在随后的处理和暴露在磷酸中时会在硅表面上造成蚀坑。研究发现，这些颗粒在HCl溶液中可以被去除，但在H_2SO_4-H_2O_2溶液中不能完全被去除。本文从吸附自由能的变化、Pourbai x图、电化学双电层厚度、硅掺杂类型、浓度等方面讨论了沉淀机理。
This paper considers the precipitation of iron oxide particles in connection with the KOH etching of cavities in silicon wafers. The findings presented in this paper suggest that the source to the particles is the KOH pellets used for making the etching solution. Experiments show that the precipitation is independent of KOH etching time, but that the amount of deposited material varies with dopant type and dopant concentration. The experiments also suggest that the precipitation occurs when the silicon wafers are removed from the KOH etching solution and not during the etching procedure. When not removed, the iron oxide particles cause etch pits on the Si surface when later processed and exposed to phosphoric acid. It has been found that the particles can be removed in an HCl solution, but not completely in an H2SO4-H2O2 solution. The paper discusses the involved precipitation mechanism in terms of the change in free energy of adsorption, the Pourbaix diagram, the electrochemical double-layer thickness and silicon dopant type, and concentration.