Objective Objectives and content The aim of the project is to achieve a fundamental physicochemical understanding of the kinetics an mechanism of chemical and electrochemical dissolution of silicon in aqueous KOH with a view to develop the next generation of ultra-high precision anisotropic wet chemical etching techniques with enhanced reliability in both anisotropic ratios and surface finish for large area devices. It is widely accepted that the crystal orientation sensitivity resulting in the anisotropic dissolution of Si is determined by orientation dependent surface chemistry. The present project is based on a fundamental Physical Chemistry approach, bringing together advanced electrochemical and surface science techniques for the understanding of the mechanism of anisotropic etching of silicon and of the origin of pyramids often observed in the etching of micromachined structures. The main industrial objectives are reliability in surface finish, with a surface roughness better than 4 nm rms, and the production of etched surfaces with anistropic ratios between the { 100} and { 111 } surfaces better than 140:1 and a ratio reproducibility better than 5%. The proposed research programme capitalises on recent advances in instrumentation and in the study of the physical chemistry of semiconductor electrodes. The proposers intend to establish a link between results obtained under UHV conditions with experiments in the condensed phase. Surface science techniques give a unique possibility for the characterisation of the state of a surface and allows to monitor the way in which organic absorbates interact with single crystal silicon by LEED, Programmed Thermal Desorption and High Resolution Electron Energy Loss Spectroscopy. In addition, other structure and chemical sensitive techniques, such as XPS provide a wealth of surface information that has not been employed until now for the characterisation of the Si-aqueous KOH interface in the presence of organic additives. Simultaneously with this type of measurements, the proposers will investigate the Si-aqueous KOH interface by a variety of powerful electrochemical techniques, such as in-situ AFM, luminescence emission, FTIR modulated Reflectance Spectroscopy, AC impedance spectroscopy and phocurrent, in an attempt to understand the band structure at the interface and the mechanism of dissolution of Si. It is of particular importance to understand if the anisotropic dissolution reaction follows a chemical or an electrochemical mechanism, or both simultaneously, and it is expected that the combination of electrochemistry and surface science methods will provide the necessary fundamental understanding for the development of practical etching baths with far superior performances than those that achieved at present by a trial and error approach. The main scientific objectives of the proposal are: To study of the elementary steps in the dissolution reaction of Si To determine the origin of anisotropy and of the chemical factors affecting anisotropic ratios. The investigate the physical chemistry of organic additives in relation to the surface chemistry of silicon To establish a relationship between semiconducting properties and Si etching. The industrial application of the proposed research are to develop: New etching formulations leading to a surface roughness of less than 4 nm rms Methods for the in situ measurement and control of anisotropic ratios of etching baths New methodologies for etching bath design. Fields of science natural scienceschemical scienceselectrochemistrynatural sciencesphysical scienceselectromagnetism and electronicssemiconductivitynatural scienceschemical sciencesinorganic chemistrymetalloidsnatural scienceschemical sciencesphysical chemistrynatural sciencesphysical sciencesopticsspectroscopy Keywords Nanotechnology Programme(s) FP4-BRITE/EURAM 3 - Specific research and technological development programme in the field of industrial and materials technologies, 1994-1998 Topic(s) 0202 - New methodologies for product design and manufacture Call for proposal Data not available Funding Scheme CSC - Cost-sharing contracts Coordinator THE UNIVERSITY OF LIVERPOOL EU contribution No data Address Crown Street L69 7ZD LIVERPOOL United Kingdom See on map Total cost No data Participants (5) Sort alphabetically Sort by EU Contribution Expand all Collapse all Druck Limited United Kingdom EU contribution No data Address Fir Tree Lane LE6 0FH Groby See on map Total cost No data Rijksuniversiteit Utrecht Netherlands EU contribution No data Address 1,Princetonplein 1 3584 CC Utrecht See on map Total cost No data Siemens AG Germany EU contribution No data Address 13623 Berlin See on map Total cost No data UNIVERSITY OF ST ANDREWS United Kingdom EU contribution No data Address Purdie Building KY16 9ST ST ANDREWS See on map Total cost No data University of Limerick Ireland EU contribution No data Address The National Technological Park 61 Limerick See on map Total cost No data
