Please provide guidance for the problem. What should I do to solve the problem about new unit pixel design?
A hypothetical client working for a technology company demands a new design for their new products. As a designer you are supposed to take the responsibility for this design assignment starting from the initial problem statement presented by the client as follows;
“The new design that you created for a unit photosensitive pixel structure in order to perform colored imaging through CMOS imaging sensor arrays worked successfully. On the other hand, the quantum efficiency values of the pixels should be improved in order for a CMOS image sensor, which is manufactured depending on this new design, to be integrated into smart phones. For this purpose, the light collection efficiency and the photon absorption efficiency of the Si photodiodes should be improved enough for a high-quality imaging results even while the pixel sizes shrink. Some portion of the light cannot reach the photodiode due to reflection from the surface and scattering from the metal lines surrounding the photodiode surface, which are formed during CMOS manufacturing steps. Due to the low absorption coefficient and indirect bandgap of Si as a semiconductor, the photodiodes should be manufactured from a different semiconductor material having a direct bandgap and high absorption coefficient in order to reach our goal. The material choice of the photodiodes and deposition methods should be compatible with the common CMOS manufacturing process. Under these circumstances, our company expects an highly efficient pixel design for our new CMOS imaging sensor chip performing colored imaging in the visible range of the light spectrum, preferably with decreased pixel size.”
At this stage you are not supposed to design a unit cell for such a purpose, literally. On the other hand, find and inspect the current design solutions for increased efficiency pixels, select one of them and assume that this will be your chosen detailed design.
