Apple keeps applying patents on global shutter pixel and its components. The US20140252201 application "Charge transfer in image sensors" by Xiangli Li, Xiaofeng Fan, and Chung Chun Wan proposes a doping structure for storage node SN, where the part near the transfer gate is lightly doped to create a potential barrier, said to be useful for multiple storage node pixels like this one:
What is the barrier height between 188 and 176 ? It should be very small. So the FWC problem is not really resolved. Am I right ?
ReplyDelete-yang ni
I think this is similar to the Aptina pump gate global shutter, and addresses the problem of transferring charge from one virtual gate to another. It is a pretty normal CCD operation. The filing date is before the Aptina IISW presentation last June. Anyway, it is about the exact doping structure, not about the CCD operation.
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