Surface erosion of hot Cr target and deposition rates of Cr coatings in high power pulsed magnetron sputtering

High power pulsed magnetron sputtering (HPPMS) of a hot chromium target by using a combined power source is the aim the present research. The combination of HPPMS technique and hot target can be effective way to produce Cr coatings. The investigations were performed by using a power supply with pulse frequency of 500 Hz, duty cycle of 4% in the range of power density averaged over pulse period from 15 to 65 W/cm2. The specific feature of the investigation is that sputtering and sublimation of the target occur simultaneously. The experimental results and the calculations revealed the important role of sublimated Cr atoms concentration near the target in increasing the pulsed and average discharge current and in setting up the self-sputtering mode. The erosion yield of the hot Cr target is determined, and in the investigated power range, it increases from 1.5 to 30 atoms per ion due to sublimation. As a result, the coating deposition rate by HPPMS from hot solid target can be increased 10-30 times in comparison to cooled target sputtering.