The electrical reliability of silicon-silicide-on-insulator (SSOI) substrates is studied by diode analysis method. Diodes are fabricated in epitaxial silicon on silicon-on-insulator (SOI) and SSOI substrates. At low reverse bias the diodes on SSOI substrates show a general increase in leakage current. However, as the reverse bias increases to 2.3 V, the leakage current for diodes on SOI substrates surpasses that on SSOI substrates. The correlation between the electrical behavior of the diodes and the threading dislocations in the epitaxial layer is explored by applying a controllable preferential etching process based on an electrochemical capacitance-voltage system. The crystal quality of the SSOI substrates is also studied by Rutherford backscattering spectrometry and channeling. (c) 2008 The Electrochemical Society. [DOI: 10.1149/1.2988046] All rights reserved.