Fabrication of Metal-High-k Capacitors on Germanium (May 2008)

The objective of this study is to gain understanding of MOS devices built on germanium. Ge PMOS transistors were simulated using Silvaco. MOS capacitors have been fabricated using hafnium oxide, a high-K dielectric, and molybdenum, a metal gate. The capacitance-voltage (CV) characteristics of the devices were obtained and studied. During the deposition of hafnium oxide on germanium substrate, the surface integrity plays a significant role. Two different surface treatments for the Ge substrates were implemented: one with NH3 immersion at 650°C for one minute, the other with a deionized (DI) water rinse for one minute. In doing so, one can examine how nitrogen passivation prior to the dielectric deposition impacts device performance compared to a standard rinse with DI water