INTERFACIAL LAYERS OF HIGH-BARRIER SCHOTTKY DIODE OF AL/N-TYPE (100)SI EXPOSED TO H-2 PLASMA

Al/Si Schottky diodes were fabricated from n-type silicon wafers which were exposed to several kinds of plasma in a magnetron using gases of hydrogen, deuterium, helium, nitrogen, oxygen and argon. The influence of plasma exposure on the Schottky barrier height is examined. The Schottky barrier height increases for only H-2-containing plasma exposure. Hydrogen plays an important role in the increase of the Schottky barrier height. The plasma-exposed silicon surfaces are characterized by transmission electron microscopy, X-ray photoelectron spectroscopy and secondary ion mass spectrometry. H-2 PlasMa exposure produces both a surface hydrogen-absorbing zone about 10 nm thick and a zone including planar defects under the hydrogen-absorbing zone. In Ar plasma exposure, the only zone including planar defects is formed from the surface to 30 nm in Si. The increase in the Schottky barrier height can be attributed to the formation of the hydrogen-absorbing zone in Si.