An improved CMOS sensor integrated circuit is disclosed comprising a photodiode, a transfer gate device, a reset transistor, a source- follower transistor, and a row-select transistor. The pinned photodiode comprises a deep n-type low-dose implant and a shallow n-type ring-shaped high-dose implant. The deep implant determines the collection depth of the photodiode; whereas the ring shallow implant increases the capacity around the edges of the photodiode and reduces the time for charge transfer.