Effects of small amount of impurities on etching of silicon in aqueous potassium hydroxide solutions

Tanaka, Hiroshi; Abe, Yoshitsugu; Yoneyama, Takao; Ishikawa, J.; Takenaka, Osamu; Inoue, Kazuyuki

doi:10.1016/s0924-4247(99)00340-4

Cited by 41 publications

(35 citation statements)

References 4 publications

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“…However, the copper ions are reduced near the surface and will adsorb in the neutral state. 24,26 For other applications, copper is usually present as a metal, but in any case, since silicon is usually doped for microelectronics purposes, it can be considered as an unlimited reservoir of electrons, and the adsorption of an initially neutral copper atom is physically valid.…”

Section: A Calculation Methodologymentioning

confidence: 99%

“…22 Theoretical predictions support the mobility of copper on a hydrogenterminated surface, 23 but the very low calculated adsorption energies are difficult to reconcile with etching experiments. 6 According to wet etching experiments in alkaline solutions, [24][25][26] Cu has a dramatic impact on the etch rate, the surface morphology, and the surface roughness of ͑110͒ and ͑100͒. During KOH etching, the surface is mostly H terminated, 27,28 although it includes a small fraction of OH terminations, 29 whose number is expected to increase with increasing KOH concentration.…”

Section: Introductionmentioning

confidence: 99%

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First-principles calculations of Cu adsorption on an H-terminated Si surface

et al. 2007

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In this study, we use first-principles simulations to study the adsorption of copper onto H-terminated and partially OH-terminated silicon surfaces. We show that, in contrast to previous studies, copper adsorbs strongly to the H-terminated silicon surface and that the adsorption energy is significantly dependent on the local bonding environment. The addition of a hydroxide group increases the average adsorption energy while reducing the range of adsorption energies due to the strong interaction between copper and oxygen. Our results predict that copper will generally prefer to adsorb at dihydride sites on the surface, agreeing with experimental studies of copper nucleation. The adsorption energy hierarchy predicted by the calculations strongly supports the suggestion that copper acts as a micromask in wet chemical etching, blocking reactive sites.

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Section: A Calculation Methodologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

First-principles calculations of Cu adsorption on an H-terminated Si surface

et al. 2007

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“…In this work it has been found both experimentally using total reflection X-ray fluorescence ͑TRFX͒ spectrometry and theoretically using free energy change of adsorption calculations, that Fe will adsorb as a Fe(OH) 3 (aq) film-type layer, instead of being adsorbed as particlelike residues on the oxidized silicon surface. These results were found for pH 11 and at a temperature of 80°C.…”

Section: Discussionmentioning

confidence: 97%

“…Precipitation, mechanism on the silicon.-According to Mori et al 10 and Beverskog et al 11 both the solid complex Fe(OH) 3 and Fe 2 O 3 are theoretically stable at pH 14 and pH 12, respectively. It could therefore be argued that one or more solid phases could precipitate and subsequently adhere to the wafers during the KOH etch- Figure 10.…”

Section: Discussionmentioning

confidence: 99%

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Particle Precipitation in Connection with KOH Etching of Silicon

Nielsen

Christensen

Pedersen

et al. 2004

J. Electrochem. Soc.

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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 H 2 SO 4 -H 2 O 2 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.

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Microstructure Controlled Porous Silicon Particles as a High Capacity Lithium Storage Material via Dual Step Pore Engineering

Sohn

Lee

Park

et al. 2018

Adv Funct Materials

120

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To overcome the lithium storage barriers of current lithium-ion batteries, it is imperative that conventional low capacity graphite anodes be replaced with other higher capacity anode materials. Silicon is a promising alternative anode material due to its huge energy densities; however, its lithiumconcentration-dependent volumetric changes can induce severely adverse effects that lead to drastic degradations in capacity during cycling. The dealloying of Si-metal alloys is recently suggested as a scalable approach to fabricate high-performance porous Si anode materials. Herein, a microstructure controlled porous Si is developed by the dealloying in conjunction with wet alkaline chemical etching. The resulting 3D networked structure enables enhancement in lithium storage properties when the Si-based material is applied not only as a single active material but also in a graphite-blended electrode.

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Effects of small amount of impurities on etching of silicon in aqueous potassium hydroxide solutions

Cited by 41 publications

References 4 publications

First-principles calculations of Cu adsorption on an H-terminated Si surface

First-principles calculations of Cu adsorption on an H-terminated Si surface

Particle Precipitation in Connection with KOH Etching of Silicon

Microstructure Controlled Porous Silicon Particles as a High Capacity Lithium Storage Material via Dual Step Pore Engineering

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