Eric Fossum put his Samsung IEDM 2011 paper on-line:
"A 192×108 pixel ToF-3D image sensor with single-tap concentric-gate demodulation pixels in 0.13 μm technology"
T.Y. Lee, Y.J. Lee, D.K. Min, S.H. Lee, W.H. Kim, S.H. Kim, J.K. Jung, I. Ovsiannikov,
Y.G. Jin, Y.D. Park, E.R. Fossum, and C.H. Chung
"A 3D-ToF FSI image sensor using novel concentric photogate [CG] pixels with single-tap operation is described. Through the use of CG structure, we are able to achieve high DC at larger pixel pitches. The new CG pixel structure substantially improves DC [demodulation contrast] to 53% at 20MHz at 28 μm pixel pitch. Recent initial results from a backside-illuminated (BSI) implementation of the same sensor show further improved performance and will be reported elsewhere."