US Patent 10541246 3D flash memory cells which discourage cross-cell electrical tunneling

3-d flash memory cells and methods of manufacture are described. The devices and methods recess a compound floating gate in between the silicon oxide slabs which reduces the quantum probability of electron tunneling between vertically adjacent storage cells. The devices and methods further include a high work function nanocrystalline metal in the compound floating gate. A polysilicon buffer layer forms a portion of the compound floating gate. The polysilicon buffer layer allows the high work function nanocrystalline metal to be selectively deposited. The polysilicon buffer layer further protects the high work function nanocrystalline metal from oxidation with the gate oxide subsequently formed on the other side.