Effects of bias voltage and gas pressure on orientation and microstructure of iridium coating by double glow plasma

Effect of substrate bias on the growth behavior of iridium on A-plane sapphire using radio frequency sputtering at low temperatures

“…In the above mentioned context, this work aims at the investigation of the effect of substrate bias on the morphology and crystallinity of iridium thin films grown at low substrate temperatures as well as the possibility to induce preferential orientation of the film in [001] direction at low substrate temperatures. In reference to the work of Tolstova et al [21], we will show that the application of a substrate bias voltage leads to an oriented growth of Ir films on A-plane sapphire (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) at low temperatures. However, in contrast to their findings for the low-T heteroepitaxial growth of gold films on magnesium oxide, we applied a substrate bias only during the early stages (i.e.…”

“…The iridium layers were deposited by rf-sputtering using a custom-build S400-S3 sputter system (FHR, Dresden, Germany) fitted with an Ir target (99,9 at.%) supplied by EVOCHEM Advanced Materials GmbH, Offenbach, Germany. The A-plane sapphire (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) substrates were purchased from Situs Technicals, Wuppertal, Germany. Prior to the deposition process, the wafers were in-situ (1x10 -7 mbar) annealed at 350 °C for 60 minutes, then Argon sputtered at 2x10 -2 mbar by 350 V bias and 200 W for 8 minutes.…”

“…The distance between target and substrate was set to 110 mm. In order to investigate the influence of substrate bias on the growing microstructure of the film we deposited three iridium layers at 350 °C on A-plane sapphire (11)(12)(13)(14)(15)(16)(17)(18)(19)(20). Sample 1 was deposited without substrate bias.…”

“…Figure 7a) depicts the theta-2-theta scan. The spectrum exhibits three diffraction peaks at 37.8°, 80.7°, and 47.2° which can be ascribed to the (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) lattice plane of the sapphire substrate and the (002) plane of the iridium layer.…”

“…Various deposition techniques have been employed to prepare oriented iridium films on different substrates [15][16][17][18][19]. Excellent film qualities were achieved with electron-beam evaporation; however, very low evaporation rates (0.1 -3 nm/min) [20] and high substrate temperatures (> 600 °C) necessary for oriented film growth limit potential substrates to high temperature resistant substrates, mostly binary oxides.…”