Numerical Analysis Of Photocurrent Distribution And The Fabrication Of Color Sensor For Panchromatic Wave Band

Based on the strong dependence of light absorption coefficient in silicon on the incident light's wavelength, silicon color sensor with double P-N junctions can detect color information of the incident light. It has been successfully used to detect the wavelength of homogeneous light, and being studied on identification of color difference and the measurement of peak wavelength of polychromatic light. With the advantages of simple structure and being realized to detect on line, silicon color sensor can be applied in many fields.Aiming at the shortage of conventional theory on the current distribution in the base region of color sensor, it is analyzed and calculated how photocurrent in the base region are distributed to deep junction and shallow junction under the function of built-up electric fields. The results are analyzed by using the software Mathematica4 2, and the numerical analysis results can be well confirmed by experiment. So the conventional theory on the current distribution is revised, and we get the result which accords with the practical current distribution.With the limit of silicon optical properties and the structure of double PN color sensor, it is difficult to let the color sensor respond well to UV-blue light. Based on the theory analysis of photocurrent distribution in the base region of color sensor, it can be found that the impurity concentration and the junction depth arc the main factors. The new color sensor for panchromatic wave band is gained through different choices of the structures of devices and technology conditions, which can enlarges the use of color sensor.