Ion assisted deposition of thin films by substrate tuned radio frequency magnetron sputtering

Abstract

The substrate tuning technique was applied to a radio frequency magnetron sputtering system to obtain a variable substrate bias without an additional source. The dependence of the substrate bias on the value of the external impedance was studied for different values of chamber pressure, gas composition and rf input power. A qualitative explanation of the results is given, based on a simple model, and the role of the stray capacitance is clearly disclosed. Langmuir probe measurements show that this system allows independent control of the ion flux and the ion energy bombarding the growing film. For an argon flow rate of 2.8 sccm and a radio frequency power of 300 W ͑intermediate values of the range studied͒ the ion flux incident on the substrate was 1.3ϫ10 20 m Ϫ2 s Ϫ1 . The maximum ion energy available in these conditions can be varied in the range 30-150 eV. As a practical application of the technique, BN thin films were deposited under different ion bombardment conditions. An ion energy threshold of about 80 eV was found, below which only the hexagonal phase was present in the films, while for higher energies both hexagonal and cubic phase were present. A cubic content of about 60% was found for an ion energy of 120 V.

Fabrication and nuclear reactor tests of ultra-thin 3D silicon neutron detectors with a boron carbide converter

“…The RF input power was 350 W, and the reflected power was reduced to zero by an impedance adapter. On the other hand the substrate bias voltage was kept to a positive value of +10 V using the tuned RF magnetron sputtering technique [14]. A reactive mixture of Ar and N 2 was introduced The resulting 10 B 4 C layer showed excellent homogeneity over the whole wafer.…”

Effect of particle bombardment on the orientation and the residual stress of sputtered AlN films for SAW devices

“…Films were grown without intentional heating on silicon (Si) (100) wafers for different values of the discharge gas composition, the total pressure, and the substrate self-bias voltage. The temperature of the films during the process remained below 200 • C. For this work, samples of series A were deposited with the substrate holder electrically isolated, and samples of series B were grown after connecting the holder to the ground through an external tuning network, which is a convenient way to control the substrate self-bias voltage [6]. A direct current (DC) bias probe formed by a RF rejection filter and a voltage divider was used to measure the DC bias substrate voltage with respect to the anode (ground).…”

Electrode impedance effect in dual-frequency capacitively coupled plasma

“…Therefore, it is important to understand the electrode impedance effect in designing a plasma process apparatus. The effect of an external circuit on plasma properties has been studied for over 20 years [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. The electrode impedance effects discussed in these studies can be categorized into linear and nonlinear effects.…”

“…The linear electrode impedance effect is caused by the impedance at the externally applied frequency. Several authors have reported the control of self-bias by using an external circuit in physical vapor deposition (PVD) chambers [1][2][3]. In their studies, 13.56 MHz RF was applied to an ICP antenna to generate plasma, and the impedance of the wafer was tuned using an external circuit.…”