Variable capacitance diodes of (p)nc-Si:H/(n)c-Si heterojunction

A structure of Au/Cr alloy electrode /multi layer of multi-layer p type hydrogenated nanocrystalline silicon (nc-Si:H) films on n type crystalline silicon c-Si/Au/Ge alloy electrode is fabricated using plasma enhanced chemical vapor deposition system and electronic beam evaporation techniques. It is confirmed by electrical measurements of I-V, C-V, C-f, and deep level transient spectrum that this is a variable capacitance diode of linear slowly varied heterojunction. The capacitance variable coefficient is much more than that of linear slowly varied single crystal silicon heterojunction namely γ=0.167. The forward conduct mechanism is satisfied to the model of tunneling aided radiation-recombination. The reverse conduction is dominated by current-generated in the space charge region. The diode shows small reverse current and high reverse breakdown voltage as well as good rectification property.