Characterizing the Role of Deformation during Electrochemical Etching of Metallic Films
- PDF / 308,128 Bytes
- 6 Pages / 432 x 648 pts Page_size
- 46 Downloads / 278 Views
Characterizing the Role of Deformation during Electrochemical Etching of Metallic Films Anil Kumar1,2 , Keng Hsu1,3, Kyle Jacobs1,3, Placid Ferreira1,3, and Nicholas X. Fang1,3,4 1 Center for Nanoscale Chemical-Electrical-Mechanical Manufacturing Systems, University of Illinois at Urbana-Champaign, IL 61801 USA 2 Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, IL 61801 USA 3 Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, IL 61801 USA 4 Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
ABSTRACT Electrochemical dissolution of ionic species into a solid is an area of great interest in several fields including nanoscale patterning and energy storage. Such dissolution is strongly influenced by several factors e.g., work function difference, dislocation density, grain size, and number of grain boundaries. These parameters are strongly influenced by mechanical deformation of the ionic conductor. Here we characterize such a system of silver (Ag) and silver sulfide (Ag2S), where incorporation of Ag into the solid ionic conductor, Ag2S, is dramatically influenced by mechanical deformation. We show more than three-fold dissolution rate enhancement when the polycrystalline conductor is compressed to one-third of its original size. We attribute this enhancement to increased dislocation density which is supported by the high current densities observed during dissolution. Additionally, reduced electronic currents suggest most of this contribution comes from increased reaction at the metal-conductor interface. Our studies have important applications in areas involving ionic transport including direct metal patterning and energy storage technology.
INTRODUCTION The incorporation of metals into compounds has several important applications in chemical, mechanical, and electrochemical processes. Li intercalation [1] has widely been used in modern batteries for energy storage. The irreversible mechanical damage during chargingdischarging has led to new ways of designing the electrodes [1]. Another important application is selective transfer of mobile species across solid ionic conductors as used in fuel cells, metal dissolution, and host of other processes. We have recently applied this idea to direct patterning of metals with sub-10 nm features using solid-state superionic conductors [2-5].
175
One such superionic conductor is Ag2S, whose high temperature α phase has been known for abnormally high conductivity [6-7]. However, the room temperature β phase has attracted more attention due to easy handling, and recent application in patterning of metal interconnects [2-5]. Most metal sulfides are brittle; however, β-Ag2S is ductile with low yield strength of ~80 MPa allowing low pressure forming of features for direct metal patterning [4, 8]. To understand the effect of forming procedures, one needs to understand the electrochemical processes and effect of deformation on these processes. Since the β-phase is a mixed co
Data Loading...
