Study of the Adhesion and Biocompatibility of Nanocrystalline Diamond (NCD) Films on 3C-SiC Substrates
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1203-J08-05
Study of the Adhesion and Biocompatibility of Nanocrystalline Diamond (NCD) Films on 3C-SiC Substrates Humberto Gomez1, 3, Christopher L. Frewin2, Ashok Kumar1,4, Stephen E. Saddow2,4, Chris Locke2 1 Mechanical Engineering Department, University of South Florida, 4202 E Fowler Ave ENB 118 Tampa, FL, 33620 USA. 2 Electrical Engineering Department, University of South Florida, 4202 E Fowler Ave ENB 118 Tampa, FL, 33620 USA. 3 Departamento de Ingeniería Mecánica, Universidad del Norte, Barranquilla, Colombia. 4 Nanomaterials & Nanomanufacturing Research Center, University of South Florida, Tampa, FL 33620 USA
ABSTRACT The unique material characteristics of silicon carbide (SiC) and nanocrystalline diamond (NCD) present solutions to many problems in conventional MEMS applications and especially for biologically compatible devices. Both materials have a wide bandgap along with excellent optical, thermal and mechanical properties. Initial experiments were performed for NCD films grown on 3C-SiC using a microwave plasma chemical vapor deposition (MPCVD) reactor. It was observed from the atomic force microscopy (AFM) analysis that the NCD films on 3C-SiC possess a more uniform grain structure, with sizes ranging from approximately 5 – 10 nm, whereas on the Si surface, the NCD has large, non-unioform inclusions of grains §1 ȝm in size. The in vitro biocompatibility performance of NCD/3C-SiC was measured utilizing 2 immortalized neural cell lines: H4 human neuroglioma (ATCC #HTB-148) and PC12 rat pheochromocytoma (ATCC #CRL-1721). MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to measure viability of the cells for 96 hours and live/ fixed cell. AFM was performed to determine the general cell morphology. The H4 cell line shows a good biocompatibility level with hydrogen treated NCD as compared with the cell treated polystyrene control well, while the PC12 cells show decreased viability on the NCD surfaces. INTRODUCTION The outstanding material characteristics of 3C-SiC and NCD present some unique solutions for the generation of high temperature, power, and high frequency MEMS devices. As semiconductor materials, 3C-SiC and NCD have very good electrical properties that can be utilized for the creation of electrical devices. The band gap difference and high carrier mobility for both of these materials generates a heterojunction that can become part of an extremely efficient and fast switching bipolar junction device [1]. As both of these materials are potentially biocompatible due to their chemical inertness, the generation of permanently implantable MEMS devices is also a possibility. Single crystal 3C-SiC is normally heteroepitaxially grown on silicon using CVD methods and the process is extremely sensitive to both growth and substrate conditions.
Alternatively, NCD can be deposited on any material stable at the deposition temperature by using microwave plasma chemical vapor deposition (MPCVD). However, NCD deposited on Si substrates possesses additional defects as the result
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