Galvanic and Chemical Deposition of Bismuth Powders from Aqueous Solutions

Djokić, Stojan S.; Djokic, Nada; Thundat, Thomas

doi:10.1149/2.016210jes

Cited by 13 publications

(20 citation statements)

References 19 publications

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“…Impurities may significantly affect the rate of many electrochemical processes, 9 including the galvanic displacement reactions. [10][11][12] In addition, the deposited metals are quite porous as observed for other galvanic displacement processes. 12,13 In this way, the rate of crystal growth is determined by the rate of substrate oxidation (dissolution) which is an anodic process and by the rate of metal ions reduction (deposition) which is a cathodic process.…”

Section: Resultsmentioning

confidence: 84%

Galvanic Deposition of Silver on Silicon Surfaces from Fluoride Free Aqueous Solutions

Djokić¹,

Cadien

2015

ECS Electrochemistry Letters

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Direct deposition of silver from fluoride-free alkaline solutions containing Ag(I) ions at pH higher than 12 onto silicon surfaces at room or elevated temperatures has been demonstrated. This deposition does not require a reducing agent, i.e. process proceeds via galvanic displacement reactions. This new process that is based on strong alkaline and fluoride-free solutions was experimentally illustrated through XRD and SEM analyses. Theoretically, it was confirmed that this process is thermodynamically favorable at room temperature, however for the real industrial applications elevated temperatures (up to 100 Semi-conductive silicon substrates are widely used in electronics industry for various applications. Metallization of silicon semiconductors with copper, silver and gold is very important in the production of integrated electronics devices. For this purpose, electrochemical methods e.g. electrodeposition or electroless deposition from aqueous solutions are very attractive since they are quite simple and relatively easy to scale up. Practical difficulties arise due to the fact that at the surface of silicon wafers oxide films of SiO 2 are formed. SiO 2 films are non-conductive, and consequently, they must be removed prior to direct metallization using the aqueous electrochemical processes. Although the metallization of silicon substrates can be achieved via autocatalytic deposition through the surface activation with SnCl 2 /PdCl 2 catalysts, 1 this process would not remove the SiO 2 film leading to an unacceptable electronic device performance. In order to remove the SiO 2 film and to deposit metals such as copper or silver from aqueous solutions directly onto silicon, various pretreatment steps are required during processing. These pre-treatment steps involve fluoride-containing solutions, 2 which can have deleterious effect on the environment. The direct deposition of copper, silver or gold from aqueous fluoride-containing solutions onto silicon substrates via the galvanic displacement reaction has been described in the literature.3-6 Reports on the deposition of copper or silver onto silicon substrates via the galvanic displacement reaction from fluoride-free aqueous solutions have not been found in the literature. The present paper describes preliminary observations on the deposition of silver onto silicon substrates via the galvanic displacement from aqueous fluoride-free solutions. Of course, significant detailed studies will be required before this process can be applied in the practice. If and when successful, this simple process may have a significant impact on the electronics industry.Experimental p-(boron doped) and n-(phosphorus doped) single crystal (100) silicon were used as substrates in the present work. As received, silicon substrates were very carefully washed with 3:1 (H 2 SO 4 -H 2 O 2 ) solution and then with water and ethanol. After the cleaning procedure, silicon substrates were immersed into respective proprietary fluoridefree solutions containing Ag(I) ions. For the deposition of sil...

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Section: Resultsmentioning

confidence: 84%

Galvanic Deposition of Silver on Silicon Surfaces from Fluoride Free Aqueous Solutions

Djokić¹,

Cadien

2015

ECS Electrochemistry Letters

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show abstract

“…Impurities may significantly affect the rate of many electrochemical reactions 9 including the galvanic displacement. [10][11][12] Additionally, the deposits are quite porous as observed for other galvanic displacement processes. 12,13 In this way the rate of crystal growth is determined by the rate of substrate oxidation (dissolution) which is an anodic process and by the rate of metal ion reduction (deposition) which is a cathodic process.…”

Section: Discussionmentioning

confidence: 80%

Galvanic Processes on Silicon Surfaces in Cu(II) Alkaline Fluoride-Free Solutions

Djokić

Antić

Djokic³

et al. 2016

J. Electrochem. Soc.

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Galvanic processes on silicon surfaces in alkaline fluoride-free solutions containing Cu(II) ions were investigated in this work. Deposition of copper (I) oxide (Cu 2 O) and copper metal at pH 14 onto silicon surfaces at room or elevated temperatures has been demonstrated. This deposition does not require the presence of a reducing agent in the solution. The results clearly show that Cu(II) ions can be reduced to Cu(I) or Cu (0) Metallization of silicon with copper, silver and gold can be realized using electrochemical methods such as electrodeposition or electroless deposition from aqueous solutions. These methods are very attractive since they are simple and relatively easy to scale up. Practical difficulties arise due to the fact that at the surface of silicon wafers, oxide films of SiO 2 are present. SiO 2 films are non-conductive, and consequently, they must be removed prior to direct metallization. Although the metallization of silicon substrates can be achieved via autocatalytic deposition through surface activation with SnCl 2 /PdCl 2 catalysts, 1 this process would not remove the SiO 2 film leading to unacceptable electronic device performance. In order to remove the SiO 2 film and to deposit metals such as copper or silver from aqueous solutions directly onto silicon, pre-treatment steps are required during processing. These pre-treatment steps may involve fluoride-containing solutions, 2 which have deleterious effects on the environment. The direct deposition of copper, silver or gold from aqueous fluoride-containing solutions onto silicon substrates via the galvanic displacement reaction can be quite successful.3-6 According to recent investigations, silver can be successfully deposited onto silicon substrates from fluoride-free aqueous solutions.7 Reports on the deposition of copper onto silicon substrates via the galvanic displacement reaction from fluoride-free aqueous solutions have not been found in the literature. In an attempt to further explore the behavior of silicon in fluoride free solutions without a presence of reducing agents in the aqueous phase, the present communication describes preliminary observations on galvanic reactions on silicon substrates using Cu(II) containing alkaline fluoride-free aqueous solutions.Experimental p-(B doped) and n-(P doped) single crystal (100) silicon wafers were used as substrates in the present work. As received, silicon substrates were very carefully washed with 3:1 (H 2 SO 4 -H 2 O 2 ) solution and then with water and ethanol. After the cleaning procedure, silicon substrates were immersed into respective proprietary fluoridefree solutions containing Cu(II) ions. Immersions were performed at pH 14 using a CuC 4 H 4 O 6 (copper tartrate) complexed solution. The pH of this solution was adjusted with NaOH. The concentration of Cu(II) ions in alkaline solutions was 3.54 g/L. The immersion solutions in the present work were used as prepared. Consequently it should be assumed that O 2 was present in the solutions during the immersion.The specific immersion ...

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“…the alkaline solutions (pH 10), while powders consisting of dendritic particles were obtained under the same conditions in the acidic solution (pH 2) [17,18]. The same shape of the particles is obtained via the same reaction on Cu substrate, indicating that pH solution plays a more crucial role on the morphology of the particles than the nature of metal substrate [17].…”

Section: J Min Metall Sect B-metall 54 (3) B (2018) 291 -300mentioning

confidence: 99%

“…Aside from the methods used for the synthesis of Ag powders, the morphology of the particles depends on the composition and kind of the solutions, the presence of complexing, buffering and reducing addition agents, temperature, cathode used, etc. [9,[17][18][19]. For example, globular powders are formed via galvanic deposition on flat aluminium substrate in…”

Section: Introductionmentioning

confidence: 99%

The particle size distribution (PSD) as criteria for comparison of silver powders obtained by different methods of synthesis and by conditions of electrolysis

Avramović

Bugarin

Milanovic

et al. 2018

J min metall B Metall

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Silver powders produced by both electrochemical (galvanostatic (DC) and potentiostatic (POT) regimes of electrolysis) and chemical processes were examined by scanning electron microscope, and particle size distribution (PSD) of the obtained particles was done. In the DC regime, the current densities of-14.4 mA cm-2 for the nitrate (NIT; powder denoted with DC(NIT)) and-13.05 mA cm-2 for the ammonium (AM; DC(AM)) electrolytes were applied. In the POT regime, the used overpotentials were-90 mV (NIT(90)) and-150 mV (NIT(150)) for the nitrate, and-625 mV (AM(625)) and-925 mV (AM(925)) for the ammonium electrolytes. Reduction with hydrazine was used for chemical synthesis (powder denoted with HYD). On the basis of SEM and PSD analysis, Ag powders were grouped into three groups. In the first group DC(AM), AM(925) and HYD powders with the (8.4-8.9 %) volume ratios were placed. In the second group were AM(625) and DC(NIT) powders with the (6.5-6.6 %) volume ratios. NIT(90) and NIT(150) powders with the volume ratios of (5.2-5.7 %) made the third group. The obtained volume ratios were correlated with the morphology of synthesized particles in order to perceive advantages and lacks of powder production via electrochemical and chemical routes.

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Galvanic and Chemical Deposition of Bismuth Powders from Aqueous Solutions

Cited by 13 publications

References 19 publications

Galvanic Deposition of Silver on Silicon Surfaces from Fluoride Free Aqueous Solutions

Galvanic Deposition of Silver on Silicon Surfaces from Fluoride Free Aqueous Solutions

Galvanic Processes on Silicon Surfaces in Cu(II) Alkaline Fluoride-Free Solutions

The particle size distribution (PSD) as criteria for comparison of silver powders obtained by different methods of synthesis and by conditions of electrolysis

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