Gated diode leakage and lifetime measurements of misfit dislocation gettered Si epitaxy

Abstract

Gated diode leakage current and minority-carrier lifetime are compared between Si wafers extrinsically gettered with epitaxial misfit dislocations and reference homoepitaxial material. The stability and gettering efficiency of the interfacial misfit dislocations have been verified by measuring leakage currents of less than 1 nA/cm2 for both gate depletion and accumulation for a large number of diodes. In either mode, the gated diodes with misfit dislocation gettering exhibited more than an order of magnitude lower leakage current than that produced by standard epi without misfit dislocations. In addition, minority-carrier generation lifetimes greater than 2 ms were typical of material extrinsically gettered via misfit dislocations, while reference epi was two to three times lower. The lifetme was found to be uniform in the near-surface region, but was drastically reduced in the immediate vicinity of the misfit locations, indicating that the defects may provide useful options in high-speed devices, latch-up control, and radiation hard devices.