Contactless method for electrical characterization of silicon-on-insulator materials

The Kelvin-probe method, in combination with surface photovoltage (SPV) measurements, is applied to the nondestructive electrical characterization of silicon-on-insulator (SOI) materials. It is shown that a simple sandwich-type electrode configuration can be used for the contactless characterization of the SOI layer, when the capacitance between the vibrating electrode and the SOI surface is much smaller than the buried-oxide (BOX) and depletion-layer series capacitances. The light-intensity dependence of the SPV gives data equivalent to common cuurent-voltage (I-V) characteristics of diodes. Thus, we call the proposed method the contactless I-V method. Lastly, we demonstrate that UV illumination is effective for applying the contactless I-V method to ultrathin SOI layers such as fully depleted SOI material.