New Developments in Processing and Control of Selected Area Laser Deposition of Carbon

Selected area laser deposition (SALD) has been used to deposit carbon from methane, hydrogen, oxygen, and argon mixtures using a third generation deposition system. The effect of two laser scanning hardware/software designs on the development of morphological instability in the resulting deposit is compared. One method uses programmed I/O using the main process control CPU to calculate and download beam position and desired laser power. Another method is presented which uses dedicated direct memory access (DMA) controllers and a dedicated counter/timer to download the required information. Its improvements to the process include better coordination between laser power and beam speed resulting in an improved beam power delivery uniformity and an improved ability to utilize one CPU for control of more of the SALD process variables.