Nickel Silicide as a Contact and Diffusion Barrier for Copper Metallization in Silicon Photovoltaics
Abstract
In this study, NiSi has been formed as the contact for copper front metallization on laboratory silicon solar cells. Transfer length method (TLM) measurements were used to examine the resistive nature of the contact. The scalability of the measurement itself was also examined. Characterization of the NiSi films for thickness, resistivity and composition were performed. Single crystal silicon solar cells were fabricated and used in temperature stress tests of the degradation of the pseudo-fill factor (pFF) and quantum efficiency (QE) to assess the capabilities of the NiSi diffusion barrier. Best contact resistivities of 7.3e-6 Ohm-cm2 with NiSi only and 4.0e-5 Ohm-cm2 with NiSi/Cu/TiN were measured. Even following a week of temperature stress, NiSi maintained solar cell performance parameters such as pseudo fill factor (pFF) and quantum efficiency (QE) better than Cu/TiN contacts without NiSi and at least as good as Ti/Pd/Ag contacts on average.
These methods and materials were applied to high efficiency, textured, solar cells with passivated tunneling contacts. The viability of NiSi in this regime was evaluated by photoluminescence (PL), optical, and TLM measurements. Although the NiSi contact was shown to damage the passivation quality of the contact, a cell capable of an open circuit voltage near 700 mV could be produced using such a contact scheme. Contact resistances as low as 1.8 mOhm-cm2 were formed, as compared with industry standard screen printed Ag contacts which form best contact resistivities in the range of 1.5 mOhm-cm2.
Library of Congress Subject Headings
Solar cells; Photovoltaic power generation; Metallizing; Nickel alloys
Publication Date
5-2017
Document Type
Thesis
Student Type
Graduate
Degree Name
Microelectronic Engineering (MS)
Department, Program, or Center
Microelectronic Engineering (KGCOE)
Advisor
Santosh K. Kurinec
Advisor/Committee Member
Michael Jackson
Advisor/Committee Member
Robert E. Pearson
Recommended Citation
Marshall, Alexander Angus, "Nickel Silicide as a Contact and Diffusion Barrier for Copper Metallization in Silicon Photovoltaics" (2017). Thesis. Rochester Institute of Technology. Accessed from
https://repository.rit.edu/theses/9472
Campus
RIT – Main Campus
Plan Codes
MCEE-MS
Comments
Physical copy available from RIT's Wallace Library at TK2960 .M37 2017