Patent ID: 9041072
Filing Date: 2015-05-26
Classification: H01L

Abstract:
1. A pixel cell, comprising: a photodiode disposed in a semiconductor substrate to accumulate image charge; a single gate oxide layer having a thickness disposed over the semiconductor substrate; a single polysilicon gate layer disposed over the single gate oxide layer, wherein the single polysilicon gate layer includes a storage gate, a transfer gate, and an output gate; a storage transistor disposed in the semiconductor substrate to store the image charge, the storage transistor including the storage gate disposed over the single gate oxide, wherein the storage gate is separated from the semiconductor substrate by only the thickness of the single gate oxide layer; a transfer transistor coupled between the photodiode and an input of the storage transistor to selectively transfer the image charge from the photodiode to the storage transistor, the transfer transistor including the transfer gate disposed over the single gate oxide layer, wherein the transfer gate is separated from the semiconductor substrate by only the thickness of the single gate oxide layer; an output transistor coupled to an output of the storage transistor to selectively transfer the image charge from the storage transistor to a readout node, the output transistor including the output gate disposed over the single gate oxide, wherein the output gate is separated from the semiconductor substrate by only the thickness of the single gate oxide layer; a first isolation fence disposed over the semiconductor substrate separating the transfer gate from the storage gate, wherein a thickness of the first isolation fence is substantially equal to a spacing distance between the transfer gate and the storage gate; and a second isolation fence disposed over the semiconductor substrate separating the storage gate from the output gate, wherein a thickness of the second isolation fence is substantially equal to a spacing distance between the storage gate and the output gate.