MRI: Acquisition of a sputtering system for contact metallization of WBG semiconductor for high temperature application in air ambient.

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Technical Abstract: Wide Band Gap (WBG) semiconductor-based devices are capable of operating in extreme environmental conditions such as high temperatures, high radiation and reactive environments because of the intrinsic properties of the semiconductors. However, usual contacts and interconnects will fail long before the semiconductor fails in harsh environments. One of the goals of the research is to explore refractory metals, their alloys and silicides as oxidation and diffusion barrier layers to protect contacts on WBG semiconductor-based devices. This major research instrumentation award will fund the acquisition of a sputtering system at Elizabeth City State University. The sputtering system will be used to deposit high temperature barrier material in vacuum. The effectiveness and reliability of the device will depend interfacial reactions (including oxygen defects and mobility or accumulation of carbon) between vacuum sputtered barrier layer ( 100 nm thick) and contacts on WBG semiconductors (SiC, GaN, and Diamond). To physically characterize interface reactions at elevated temperatures, Rutherford Backscattering Spectrometry (RBS), Auger Electron Spectroscopy (AES), and Electron Microscopy (TEM & SEM) will be employed. The stability of the electrical characteristics of a simple schottky device will indicate the effectiveness of the barrier layer in harsh environment. Access to a sputtering system will also enable us to explore new collaborations with the center for materials research at Norfolk State University and Varicon Inc. in the field of "smart windows" for efficient energy use in buildings. For this and similar applications, solar materials called chromogenic materials (mostly doped transition metal oxide) will be deposited with the sputtering system and characterized locally and by collaborators.Non-technical Abstract: This major research instrumentation award funds the acquisition of a sputtering system at Elizabeth City State University. The sputtering system will be used to deposit high temperature metallic nano-layers (layers with thickness of about one-thousandth the thickness of human hair) in vacuum. The metallic nano-layers will be explored as barrier layer to protect devices fabricated on Wide Band Gap (WBG) semiconductors (SiC, GaN, Diamond, etc). These semiconductors have intrinsic properties that make them capable of surviving in harsh environmental conditions such as high temperature, high radiation and reactive environment. However, usual contacts will fail readily under extreme environmental conditions if not protected, limiting the WBG semiconductor-based device capability. Specialized electronic devices (including high power switches, sensors, controls and power management for aerospace and automotive industries) capable of operating at such extreme conditions can be located inside automobile engine block for more efficient fuel consumption and reduced atmospheric pollution (due to incomplete gas combustion). In ambient air at elevated temperature, reaction between adjacent layers in a composite contact metallization structure is one of the factors that will limit the reliability and effectiveness of WBG semiconductor-based devices. One of the primary goals is to study such reactions using state-of-the-art, high technology equipment for surface analysis. A simple schottky diode device with appropriate protective barrier layer will be evaluated in ambient air at high temperatures over an extended period of time. The stability of the devices electrical characteristics will imply the effectiveness of the barrier layer. Access to a sputtering system will also enable the team to explore new collaborations with the center for materials research at Norfolk State University and Varicon Inc. in the field of "smart windows" for efficient energy use in buildings. For this and similar applications, solar materials called chromogenic materials (mostly doped transition metal oxide) will be deposited with the sputtering system and characterized locally and by collaborators.