title: Effects of ultrasonic agitation and surfactant additive on surface roughness of Si (111) crystal plane in alkaline KOH solution.
abstract: In the silicon wet etching process, the "pseudo-mask" formed by the hydrogen bubbles generated during the etching process is the reason causing high surface roughness and poor surface quality. Based upon the ultrasonic mechanical effect and wettability enhanced by isopropyl alcohol (IPA), ultrasonic agitation and IPA were used to improve surface quality of Si (111) crystal plane during silicon wet etching process. The surface roughness Rq is smaller than 15 nm when using ultrasonic agitation and Rq is smaller than 7 nm when using IPA. When the range of IPA concentration (mass fraction, wt%) is 5-20%, the ultrasonic frequency is 100 kHz and the ultrasound intensity is 30-50 W/L, the surface roughness Rq is smaller than 2 nm when combining ultrasonic agitation and IPA. The surface roughness Rq is equal to 1 nm when the mass fraction of IPA, ultrasound intensity and the ultrasonic frequency is 20%, 50 W and 100 kHz respectively. The experimental results indicated that the combination of ultrasonic agitation and IPA could obtain a lower surface roughness of Si (111) crystal plane in silicon wet etching process.
authors.affiliation: Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Nanhu Road, Changchun 130033, Jilin, China. Electronic address: jqbyyawyx@163.com.
authors.forename: Qingbin
authors.initials: Q
authors.lastname: Jiao
authors.affiliation: Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Nanhu Road, Changchun 130033, Jilin, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Tan
authors.affiliation: Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Nanhu Road, Changchun 130033, Jilin, China.
authors.forename: Jiwei
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Nanhu Road, Changchun 130033, Jilin, China.
authors.forename: Shulong
authors.initials: S
authors.lastname: Feng
authors.affiliation: Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Nanhu Road, Changchun 130033, Jilin, China.
authors.forename: Jianxiang
authors.initials: J
authors.lastname: Gao
keywords: Surface roughness; Surfactant additive; Ultrasonic agitation; Wet etching