AVS 47th International Symposium
    Surface Science Wednesday Sessions
       Session SS-WeP

Paper SS-WeP36
Laser Etching of Si with NF3 using CuBr Laser

Wednesday, October 4, 2000, 11:00 am, Room Exhibit Hall C & D

Session: Poster Session
Presenter: B. Ivanov, University of Chemical Technology & Metallurgy, Bulgaria
Authors: B. Ivanov, University of Chemical Technology & Metallurgy, Bulgaria
K. Woynov, University of Chemical Technology & Metallurgy, Bulgaria
M.P. Tarassov, Central Laboratory of Mineralogy and Crystallography, Bulgaria
L. Zambov, University of Chemical Technology & Metallurgy, Bulgaria
V. Shanov, University of Chemical Technology & Metallurgy, Bulgaria
Correspondent: Click to Email
Laser induced thermal etching of Si using focused copper bromide vapor laser beam with wavelengths of 510 and 578 nm on monocrystalline Si (100) with NF3 gaseous phase was presented. The laser average power was in the range 4-10 W with repetition rate - 20 kHz and pulse duration - 60 ns. The process parameters were varied in the ranges: scanning speed from 10 to 1000 microns/s, substrate temperature from 100 to 400 C and partial pressure in the range of 100 - 1000 mbar. The etching products were estimated on the base of thermodinamcal calculation. The width, depth and cross section of the etched channels were investigated by Scanning Electron Microscopy (SEM). Some residues on the side wall are removed by subsequent thermal wet etching in KOH solution. In some cases we find evidence for waveguiding effect of laser radiation during the laser etching. The etching rate increases with the scanning speed and is in the range of 2.10^5 - 5.10^6 micron^3/s for the scanning speed of 10 micron/s to 1 mm/s. The aspect ratio of laser etched groves are in the range of 5 - 40 for all structures and reaches 100 for waveguiding part of the trench. This very high etching rate allows using of such process for micromachining of Si. Application of this approach for production of square rods array and field emission like tips was presented.