Albert Theuwissen continues his excellent ISSCC report series. The second part talks about stacked sensors:
Olympus presented "A rolling-shutter distortion-free 3D stacked image sensor with -160 dB parasitic light sensitivity in-pixel storage node", by J. Aoki
Sony presented "A 1/4-inch 8M pixel back-illuminated stacked CMOS image sensor" by S. Sukegawa
From what Albert writes, I'd bet that Olympus was granted an early access to Sony stacked sensor process, so that both presentations rely on the same technology.