Evaluation of the Interface Properties of Recombination Sensors From the Measurement of Capacitance-Voltage Characteristics

The problem of silicon substrate selection for the sensor structure based on deep junction barrier has been investigated. The described sensor is functioning on photoelectrical conversion principle for the illumination with has high absorption coefficient in the silicon. The method of substrate pre-selection with the measurement of capacitance-voltage characteristics has been suggested. As shape of the capacitance-voltage curves in the system liquid analyte/silicon substrate (with or without chemically modified silicon surface) highly depends on charge state of the interface and near-surface band bending, some recommendation for silicon substrate choosing can be used. The obtained results indicate that the shift of the saturation voltage of the capacitance-voltage curves correlates with peculiarities of photocurrent distribution in the deep silicon barrier structure. Based on the results of the research the effective recombination sensors with reproducible characteristics can be fabricated.