Utilization of electroluminescence from avalanche p-n junctions for optical testing of silicon integrated circuits

The most appealing technique for contactless testing of the integrated circuit die has been determined to be through the use of optical signals in the visible or infrared region to supply test signals to and from the integrated circuit chip. The generation of light in silicon for the purpose of producing the output optical signal is difficult. Silicon, being an indirect bandgap semiconductor, is a poor material for light emission. The light-emission properties of a reverse biased silicon diode under avalanche breakdown are being investigated. The intensity of this emission is low; however, for the purpose of this technique, the emission strength is only limited by the ability to detect the signal a short distance away, indicating its potential as a suitable light source for contactless testing. Many diode geometries of p-n junctions for light emission have been designed and fabricated on silicon substrates. The design criteria for these studies are to optimize photon emission from the smallest junction area. The processing parameter optimization is aimed at obtaining low breakdown voltages and minimum power dissipation