Presentation on theme: "Development and Application of a New Method for Epitaxial Growth of Metals, Alloys and Multilayers by Surface Limited Redox Replacement Nikolay Dimitrov,"— Presentation transcript:
Development and Application of a New Method for Epitaxial Growth of Metals, Alloys and Multilayers by Surface Limited Redox Replacement Nikolay Dimitrov, SUNY at Binghamton, DMR Protocols for coating with ultra thin and continuous Au and Ag layers of Ni films used in electronic circuitry were developed. The work is aimed at alleviating sporadic reliability issues with Pb-free soldering on the Ni. It was found by AFM and CV (Pb UPD) characterization that 20 nm thick Ag layers were best deposited by surface limited redox replacement (SLRR), while the same thickness of Au was best grown by a combination of (initially) defect mediated growth (DMG) and (later on) surfactant mediated growth (SMG). A detailed scanning probe study of the SLRR mechanism revealed important aspects of the critical role of the underpotentially deposited (UPD) sacrificial layer (SL) in maintaining the quasi-2D growth. It was proven by separating the deposition on (i) surface pre- coated with SL and (ii) bare surface that the SL not only powers up the exchange reaction but also serves as tool for evenly spreading the growing atoms on the surface (adsorption driven process). CV stripping experiments ascertained the larger portion of deposit expected on the SL pre-coated surface. Ni layer on Cu Ni layer coated with Au by SMG Ni layer coated with Ag by SLRR 60 ML of Ag grown on Au (111) in Local Cell Configuration 50 ML of Ag grown on Au (111) in SLRR Configuration Bare Au
Dissemination: A large portion of the work on voiding in electro-deposited Cu – Pb-free solder joints that has been (in part) supported by this grant was presented as invited talk by N. Dimitrov at 215 th ECS Meeting. Graduate students Yihua Liu (The ECS Travel Award) and Fred Wafula also attended. Dr. Natasa Vasiljevic Department of Physics, University of Bristol, UK Professional Development In November 2008, Lasantha Viyannalage defended his largely sponsored by this grant Ph.D. thesis Development of a New Method for Epitaxial Growth of Metals and Multilayer Structures by Surface Limited Redox Replacement in One Pot Configuration. During the summer of 2009 Stephanie Geer was appointed on a REU fellowship position with our group. Stephanie was identified as best candidate based on her volunteer work with us last summer. Development and Application of a New Method for Epitaxial Growth of Metals, Alloys and Multilayers by Surface Limited Redox Replacement Nikolay Dimitrov, SUNY at Binghamton, DMR Understanding, Controlling and Minimizing the Voiding, Sporadically Occurring in Solder Joints with Electroplated Copper o C Lasantha Viyannalge received his Ph.D. degree in December For him INSIDE BINGHAMTON UNIVERSITY wrote: An excellent research ambassador for Binghamton, Viyannalages success has taken him to seven national and international conferences, as well as national and international research labs. Stephanie Geer, a junior student at SUNY Brockport is currently doing REU research with our group for the summer. She has been developing different strategies for plating Sn layer with controllable microstructure for a project aiming at studying post-deposition whiskering occurring spontaneously in Sn electrodeposited films. Dr. Eric Cotts Ongoing Collaborations Studies of the SLRR mechanism have been carried out in collaboration with Dr. Natasa Vasiljevic from University of Bristol, UK. Work on the catalytic activity of Pt x Cu (1-x) alloy nanocubes has been performed in collaboration with Dr. Fangs group at SUNY Binghamton. Voiding in Cu-solder joints and Sn whiskering have been studied with Dr. Cotts group at SUNY Binghamton.