Fabrication of GaAs metal-oxide-semiconductor capacitors (MOSCAPs) with an unpinned interface is reported. The MOSCAP structure consists of a few monolayers of germanium grown in a molecular beam epitaxy (MBE) system in order to terminate an MBE-grown silicon-doped (100) GaAs layer. An ex situ HfO 2 high-κ dielectric with an equivalent oxide thickness of 12 A was deposited by using a dc magnetron sputtering system. A midgap interface state density (D it) of 5 × 10 11 eV -L cm -2 was measured using the high-frequency conductance technique. A rapid thermal annealing study was performed in order to examine the integrity of the gate stack at different temperatures. In addition, a forming gas anneal at 400 °C appears to significantly reduce the midgap D it revealed by probing the frequency dispersion behavior of the MOSCAPs.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)