Patent ID: 8218042
Filing Date: 2012-07-10
Classification: H01L,H04N

Abstract:
1. A method of operating a solid-state image-sensing device comprising a plurality of pixels, wherein each pixel comprises: a buried photodiode (PD) formed on a substrate and adapted to generate a photoelectric charge commensurate with an amount of incident light, the buried photodiode (PD) adapted to accumulate therewithin the resulting photoelectric charge; a first transistor (T a second transistor (T a third transistor (T a fourth transistor (T the method comprising the following steps in sequence: setting the third electrical signal (φV) to a low voltage sufficient to turn off the fourth transistor (T setting the first electrical signal (φTX) to a medium voltage level and setting the second electrical signal (φRS) to a high voltage, the first electrical signal (φTX) and the second electrical signal (φRS) being sufficient to make a potential at the transfer gate (TG) lower than a potential at the buried photodiode (PD) and to make a potential at the floating diffusion layer (FD) nearly equal to a potential of the direct-current voltage (VPD); setting the third electrical signal (φV) to a pulse of high voltage, the high voltage of the third electrical signal (φV) being greater than the low voltage of the third electrical signal (φV) and being sufficient to turn on the fourth transistor (T setting the third electrical signal (φV) to the low voltage of the third electrical signal (φV); setting the second electrical signal (φRS) to a low voltage, the low voltage being less than the high voltage of the second electrical signal (φRS), and being sufficient to turn off the second transistor (T setting the first electrical signal (φTX) to a high voltage level sufficient to cause the buried photodiode (PD) to transfer accumulated potential therein to the floating diffusion layer (FD), the high voltage level of the first electrical signal (φTX) being greater than the medium voltage level of the first electrical signal (φTX); setting the first electrical signal (φTX) to a low voltage level lower than the medium voltage level of the first electrical signal (φTX) and being sufficient to inhibit transfer of accumulated potential by the buried photodiode (PD) to the floating diffusion layer (FD); setting the third electrical signal (φV) to a pulse of the high voltage of the third electrical signal (φV) ; setting the third electrical signal (φV) to the low voltage of the third electrical signal (φV); setting the first electrical signal (φTX) to the medium voltage level of the first electrical signal (φTX); and setting the second electrical signal (φRS) to the high voltage of the second electrical signal (φRS) to turn on the second transistor (T