Crosstalk and microlens study in a color CMOS image sensor

The paper describes results of crosstalk investigations and microlens (mu-lens) scan experiments in a color CMOS image sensor with active pixel structure [1]. The investigation of optical and electrical crosstalk was made on 7.8- and 5.6-mum pixels by using samples with continuos shift of color filter (CF) and mu-lens across the array. As a result of this investigation, the distribution of sensitivity inside a pixel has been determined. By using minimum crosstalk criteria, the optimum parameters of the mu-lens manufacturing process and optimum position of the mu-lens was determined. The paper presents color maps of pixel sensitivity and crosstalk criteria as well as snapshots illustrating sensitivity distribution and collection area. The paper presents spectral characteristics measured at different relative apertures (f-number) as well. The quantitative analysis of spectral responses allowed us to determine the contribution of each component to the overall crosstalk.