Hydrogen-Assisted Sputtering Growth of TiN on Ceramic Substrates

Abstract

Titanium nitride (TiN) has mechanical and electrical characteristics applicable for very large scale integration (VLSI) and discrete electronic devices. This study assessed the effect of hydrogen on sputtering growth of TiN on ceramic substrates. Although ceramic substrate is used in discrete device applications due to its insulating property, ceramic is also porous and contains oxygen and water vapor gases, which can be incorporated into TiN films during growth. In addition, discrete devices are usually packaged in glass sealing at 700 °C, and reaction with the trapped gases can significantly degrade the quality of the TiN film. In order to evaluate ways to minimize the effects of these gases on TiN, hydrogen gas was introduced during sputtering growth. The main hypothesis was that the hydrogen gas would react with oxygen to lower the oxygen density in the vacuum chamber, which would suppress the effects of the trapped gases in the ceramic and ultimately improve the quality of the TiN film. Improvements in TiN quality were confirmed by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and resistance measurements. During the glass-sealing process, N2-purging at 400 °C was effective at keeping the TiN in a low resistance state. These results show that introducing hydrogen gas during sputtering growth could solve the problems caused by ceramic substrates.