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Factors affecting deposition rate of target film

Magnetron sputtering is a physical vapor deposition method, which can deposit a variety of materials, including metal targets, alloy targets, ceramic targets, etc., by using a specially formed magnetic field applied to a diode sputtering target. Deposition rate or film forming rate is an important parameter to measure the efficiency of magnetron sputtering machine. There are many factors affecting the deposition rate, including the type of the working gas, the pressure of the working gas, the temperature of the sputtering target, the strength of the magnetic field, etc. There are three important factors affecting the deposition rate of magnetron sputtering target: sputtering voltage, current and power.

Sputtering voltage
The effect of sputtering voltage on film forming rate has such a law: the higher the voltage, the faster the sputtering rate, and this effect is moderate and gradual in the range of energy required by sputtering deposition. Among the factors affecting the sputtering coefficient, the discharge voltage is really important after sputtering target and sputtering gas. Generally speaking, in the normal magnetron sputtering process, the higher the discharge voltage, the greater the sputtering coefficient, which means that the incident ions have higher energy. Therefore, the atoms of the solid target are more easily sputtered and deposited on the substrate to form films.

The sputtering current
The sputtering current of the magnetron target is proportional to the ion current on the surface of the target, so it is also an important factor affecting the sputtering rate. Magnetron sputtering has a general rule, that is, the fastest deposition speed under the best pressure (according to different sputtering target and different sputtering items. Therefore, under the premise of not affecting film quality and meeting customer requirements, it is appropriate to consider the best value of gas pressure from the sputtering yield. There are two ways to change the sputtering current: change the working voltage or change the working gas pressure.

Sputtering power
The effect of sputtering power on deposition rate is similar to that of sputtering voltage. Generally speaking, increasing the sputtering power of magnetron target can improve the film forming rate. However, this is not a universal rule. In the case of low sputtering current of magnetron target (for example, about 200 VOLTS) and large sputtering current, although the average sputtering power is not low, ions can not be sputtered or deposited. The prerequisite is that the sputtering voltage applied to the magnetron target is high enough so that the energy of the working gas ions in the electric field between the cathode and anode is greater than the sputtering energy threshold of the target.

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