Methods for producing image sensors having multi-purpose architecture
View Patent ↗A charge-coupled device (CCD) image sensor includes multiple vertical charge-coupled device (VCCD) shift registers and independently-controllable gate electrodes disposed over the VCCD shift registers and arranged into physically separate and distinct sections that are non-continuous across the plurality of VCCD shift registers. The CCD image sensor can be configured to operate in two or more operating modes, including a full resolution charge multiplication mode.
1. A method for producing an image sensor comprising an array of pixels that includes vertical charge-coupled device (VCCD) shift registers, the method comprising:
forming a first layer of gate electrodes over the VCCD shift registers;
forming a physical gap in the first layer of gate electrodes such that first and second sections of gate electrodes in the first layer of gate electrodes are produced and are physically separated and electrically isolated from each other;
forming a second layer of gate electrodes over the first and second sections of gate electrodes in the first layer; and
forming another physical gap in the second layer of gate electrodes such that first and second sections of gate electrodes in the second layer of gate electrodes are produced and are physically separated and electrically isolated from each other.
2. The method as in claim 1 , further comprising:
forming a subsequent layer of gate electrodes over a previous layer of gate electrodes; and
forming another physical gap in the subsequent layer of gate electrodes such that first and second sections of gate electrodes in the subsequent layer of gate electrodes are produced and are physically separated and electrically isolated from each other.
3. The method as in claim 1 , wherein the gate electrodes in the first layer are substantially perpendicular to the VCCD shift registers.
4. The method as in claim 1 , wherein the physical gap in the first layer of gate electrodes (i) is substantially parallel to the VCCD shift registers and (ii) extends across the entire array of pixels.
5. The method of claim 1 , wherein each of the first and second sections of gate electrodes in the first layer is disposed within a different section of the image sensor configured for independent operation.
6. The method of claim 1 , wherein (i) the first section of gate electrodes in the first layer extends over a first plurality of VCCD shift registers, (ii) the second section of gate electrodes in the first layer extends over a second plurality of VCCD shift registers different from the first plurality of VCCD shift registers, (iii) the first section of gate electrodes in the second layer extends over the second plurality of VCCD shift registers, and (iv) the second section of gate electrodes in the second layer extends over the second plurality of VCCD shift registers.