Single Langmuir Probe Measurements in an Unbalanced Magnetron Sputtering System

Abstract

The measurements of plasma parameters from inside a plasma boundary give more accurate results. Current-voltage (I-V) characteristics were obtained from plasma measurements in an unbalanced magnetron sputtering system using a Langmuir probing technique which collects the measured data from a biased probe inserted inside the plasma. These I-V characteristics were used to analyze the plasma parameters such as plasma potential, electron temperature and electron density during sputter deposition of Ti thin films. The spatial distribution of the plasma was measured at different distances from the cathode target, such as 6, 8 and 10cm. At 8cm distance from the cathode target, the plasma parameters were investigated at different distances along the target radius such as 1, 2 and 3cm. The plasma parameters of sputtered Ti thin films were investigated at different deposition conditions. The effect of the position of the single Langmuir probe and deposition conditions on the plasma parameters was studied. The plasma potential was found in the range of 4.4-5.0V. An electron temperature was found in the range of 0.8-2.2eV, corresponding to a plasma density in the range of 5.5×1017-1.2×1018 m-3. The plasma parameters strongly depended on the position of the probe and deposition conditions.