SURFACE TYPE CONVERSION OF INP BY H2S PLASMA EXPOSURE - A PHOTOEMISSION INVESTIGATION

The surface chemistry and the electronic structure of InP(100) before and after exposure to a H2S plasma was investigated by synchrotron radiation soft x-ray photoemission spectroscopy. The low power H2S plasma was generated with a commercial electron cyclotron resonance plasma source using H2S with the plasma exposure being performed as a function of incident angle and temperature. Plasma species were identified with optical emission spectroscopy. In situ photoemission measurements were acquired after each plasma exposure in order to observe changes in the valence band electronic structure as well as changes in the In 4d, P 2p, and S 2p core lines. The results were correlated in order to relate the plasma species and characteristics to changes in surface chemistry and electronic properties. These measurements indicate that the H2S plasma exposure type converts the p-type InP(100) surface to an n-type surface resulting in a shallow homojunction interface.