Rapid Synthesis of Dielectric Films by Microwave Assisted CVD
- PDF / 4,327,876 Bytes
- 12 Pages / 612 x 792 pts (letter) Page_size
- 78 Downloads / 199 Views
0929-II02-06
Rapid Synthesis of Dielectric Films by Microwave Assisted CVD Nicholas Ndiege1, Vaidyanathan Subramanian2, Mark Shannon3, and Rich Masel4 1 Chemistry, University of Illinois, 600 S. Mathews ave, Urbana, IL, 61801 2 Chemical & Biomolecular Engineering, University of Illinois, 600 S. Mathews ave., Urbana, IL, 61801 3 Mechanical & Industrial Engineering, University of Illinois, Urbana, IL, 61801 4 Chemical & Biomolecular Engineering, University of Illinois, 600 S. Mathews ave, Urbana, IL, 61801 Typical methods for the deposition of high quality films require high temperatures and/or high vacuum and have characteristically slow deposition rates. In this paper we describe a novel deposition technique: Microwave assisted chemical vapor deposition (MACVD). This technique produces films of high quality at unusually high deposition rates (>1µm a minute) at ambient pressures and temperatures slightly above room temperature. The equipment used is very inexpensive compared to that used in the conventional techniques such as epitaxy, LPCVD, e-beam evaporation, sol-gel. In this study we employ MACVD in the deposition of high k dielectric films. Such materials are typically transition metal oxides with k values such as 65 for α Ta2O5 and 14.2 for FeO compared to SiO2 at ~4.4. [1] The challenges faced in employing these materials as dielectric barriers are mobility degradation and, more significantly, the formation of a silicide interface between the substrate and oxide film that compromises the overall dielectric properties of the film. [2] High k dielectric films (specifically Ta2O5) are also appealing in the fabrication of selective emitters for use in thin film insulation and anisotropic heat expulsion for refractory environments. The challenge posed by this application is that fabrication of metal oxide films of over 1µm thickness is plagued by very low growth rates, extensive film cracking, buckling and even catastrophic delamination. [3-5] Film properties are highly dependent on the method of deposition employed, and up to this time, none of the commonly used techniques (e.g. e-beam assisted deposition, sputtering, sol-gel) has been able to yield film coatings that overcome the limitations thus cited. This has led to the quest for novel and economically viable deposition techniques that will be able to satisfy the demands put forth for microelectromechanical applications, without putting too much strain on the environment. [2, 7, 8] In this study, we report the deposition of Ta2O5 films on silicon via microwave assisted chemical vapor deposition at atmospheric conditions using a domestic microwave oven. The resulting films are also characterized and probed for various chemical, physical and optical properties. Dense and stable films of thickness ranging from 60nm to 62µm have been deposited in this manner. To the best of our knowledge, this is the first time a microwave field has been applied to the substrate and precursor to assist in the ambient metallorganic chemical vapor deposition of any dielectric. The m
Data Loading...
