Modulate the deposition rate through changing the combination of frequency and pulse width at constant duty cycle

Due to the large degree of ionization of the sputtered flux and high quality film fabrication, high power pulsed magnetron sputtering (HPPMS) is widely used. However, compared with DC sputtering, low deposition rate is probably the drawback of the HPPMS technique and restricts its application. In order to increase the deposition rate of HPPMS, different combinations of frequency and pulse width at a constant duty cycle were used to modulate the deposition rate of the Ti film. The results showed that wider pulse width would be more effective than increasing frequency on improving titanium deposition rate for a constant duty cycle. The pulse width also would affect the power utilization ratio. Especially for a high duty cycle of 4.8% and 5.6%, a wider pulse was favorable to make full use of power on film deposition, resulting in a higher normalized static deposition rate. Meanwhile, with increase in pulse width for a constant duty cycle, adatom mobility and the deposition rate increased, contributing to growth of crystallite size and higher surface roughness of Ti thin films.