Thin Films of Metals and Inorganic Compounds Vacuum Deposited by High Energy Laser

Abstract

It has been established by many workers that the rate of deposition is an important parameter for the properties of thin films produced in vacuum. However, the velocity of the vapor atoms (kinetic energy) seems to play an even more important role which is being realized only more recently with the greater application of the sputtering technique for the deposition of thin films where much larger velocities are achieved. Films obtained by sputtering show some remarkable differences in adhesion, stability of electrical properties¹, low temperature coefficient of electrical resistance, a. o., although the deposition rate may be the same as the deposition rate achieved with conventional thermal evaporation (resistance heating or electron beam heating) or even less. The difference should be due to the much higher velocity of sputtered vapor atoms². A sputtered atom already brings with itself a kinetic energy equivalent to at least the condensation heat; it is of the order of 5–10 eV or more. By changing the deposition rate with conventional thermal evaporation sources the velocity is not affected so much, since it is only a function of the square root of the temperature, whereas a much greater change of the vapor density occurs. Applying a high intensity laser, velocities can be obtained which are comparable with those achieved with the non-thermal sputtering process.

Presented at the Summer Workshop “Laser Interaction and Related Plasma Phenomena” at Rensselaer Polytechnic Institute, June 9–13, 1969 and partly included in a paper co-authored by H. A. Tourtellotte, “Vacuum Deposition by High-Energy Laser with Emphasis on Barium Titanate Films, J. Vac. Sci. Technol. 6, 373–378 (1969).