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2007
Conference Paper
Titel
Position and time resolved optical emission spectroscopy and film properties of ITO films deposited by high power pulsed magnetron sputtering
Abstract
HPPMS has been used to sputter an ITO target under various conditions. The impact of charge voltage on target material ionization was studied in detail by time- and spatially-resolved optical emission spectroscopy. The ionization was found to increase dramatically with charge voltage, which also defines the maximum current density at the target. The ions are strongly focussed in the racetracks of the target while neutral species exhibit a broader distribution. By shortening the duration of the discharge pulses the transition of the glow discharge to an arc could be prevented. This effect was used to further increase the ionization effect. The higher charge voltages used also resulted in a faster ignition and ionization onset. When examining the time evolution of the emission of the individual species a saturation was observed during the individual pulse for neutral indium, despite the target current changing dramatically during the pulse. This effect is still not understood. In order to study the effect on film growth, ITO films were deposited on unheated substrates at various charge voltages. The film growth was found to be more oxygen dominated at higher charge voltages due to the ionization affecting mainly indium.