Effect of organic contamination on the electrical degradation of hydrogen-terminated silicon upon exposure to air under ambient conditions

The degradation of the electrical characteristics of hydrogen-terminated silicon (both n- and p-doped) under typical laboratory environments was investigated. When a hydrogen-terminated silicon (H-Si) surface was exposed to air under ambient conditions, the current density/bias voltage (J-V) curve of the mercury-silicon junction thus formed changed significantly during the first 50 h. For n- type H-Si surfaces, the J-V curve initially maintained ohmic characteristics for a period of 8-12 h, then evolved to diode behavior; for p-doped samples, the current density showed a rapid increase and reached a maximum in about 20 h. In both cases, the electrical property was recovered to some extent after sonication in organic solvents. In agreement with infrared spectroscopic results, organic contamination upon exposure to ambient air is suggested to play an important role in the change of the electrical performance of hydrogen-terminated silicon. (C) 2003 The Electrochemical Society.