| AVS 63rd International Symposium & Exhibition | |
| Applied Surface Science | Thursday Sessions |
| Session AS+SS-ThM |
| Session: | Depth Profiling, Buried Interfaces, and 3D Analyses |
| Presenter: | Sukti Chatterjee, Applied Materials Inc. |
| Authors: | S. Chatterjee, Applied Materials Inc. L. Scudder, Applied Materials Inc. P. Narwankar, Applied Materials Inc. |
| Correspondent: | Click to Email |
In 1956, Porous silicon (PS) was accidentally discovered by Uhlir at Bell Laboratories [1], and t he material was very much ignored. Later (70’s and 80’s) porous Si was found to be useful because its high surface area [2-5] for various applications, like microcavity, broadband AR coating, mid infrared LEDs, chemical Sensors, smart Dust, pressure Sensor, photonic crystal. Recent interest of porous Si is in the biomedical field [6] with wide range of applications, ex. drug delivery, cancer therapy, and tissue engineering. For diverse applications, single or multilayers porous Si stacks are required. In this abstract we present our metrology invention for single or multilayers porous Si stacks analysis.
We introduce a novel approach to characterize the different Si film stacks by using Model Based Infrared Reflectometry (MBIR). We believe, we are first group to apply the technique for analyzing various multilayer Si stacks. The film stack thickness has varied between 1 μm to more than 100 µm. Thick layers of silicon are opaque in the UV-VIS wavelength range, and IR wavelengths are ideal for measurements of such films. The ability to specify a film stack in the MBIR analysis model makes the technique more versatile, compared to traditional FTIR. We will present in the conference how the IR optical properties of PS can be described by Bruggeman Effective Medium Approximation (EMA), employing a standard multilayer reflectance model. To validate the MBIR results x-SEM and Gravimetric analysis have been used. The results have shown MBIR to be a suitable technique for characterization and production monitoring of the process steps associated with the new porous silicon applications field.
References
1. Uhlir, A., Electrolytic shaping of germanium and silicon. Bell System Tech. J., 1956. 35: p. 333-347.
2. Gupta, P., V.L. Colvin, and S.M. George, Hydrogen desorption kinetics from monohydride and dihydride species on Si surfaces. Phys. Rev. B, 1988. 37(14): p. 8234-8243.
3. Gupta, P., et al., FTIR Studies of H2O and D2O Decomposition on Porous Silicon. Surf. Sci., 1991. 245: p. 360-372.
4. Dillon, A.C., et al., FTIR studies of water and ammonia decomposition on silicon surfaces. J. Electron Spectrosc. Relat. Phenom., 1990. 54/55: p. 1085-1095.
5. Dillon, A.C., et al., Diethylsilane Decomposition on Silicon Surfaces Studied using Transmission FTIR Spectroscopy. J. Electrochem. Soc., 1992. 139(2): p. 537-543.
6. Porous Silicon for Biomedical Applications, Edited by: H.A. Santos ISBN: 978-0-85709-711-8