Passive devices for 3D non-volatile memory
Passive devices such as resistors and capacitors are provided for a 3D non-volatile memory device. In a peripheral area of a substrate, a passive device includes alternating layers of a dielectric such as oxide and a conductive material such as heavily doped polysilicon or metal silicide in a stack. The substrate includes one or more lower metal layers connected to circuitry. One or more upper metal layers are provided above the stack. Contact structures extend from the layers of conductive material to portions of the one or more upper metal layers so that the layers of conductive material are connected to one another in parallel, for a capacitor, or serially, for a resistor, by the contact structures and the at least one upper metal layer. Additional contact structures can connect the circuitry to the one or more upper metal layers.
1. A passive device, comprising:
a stack formed on a substrate, the stack comprising alternating layers of a conductive material and a dielectric material, the stack is formed in a peripheral region of the substrate, lateral of a 3D stacked non-volatile memory cell array on the substrate, and the alternating layers of the conductive material and the dielectric material comprise at least a first set of the alternating layers, and a second set of the alternating layers above or below the first set of the alternating layers and arranged vertically with the first set of the alternating layers, the first set of the alternating layers is part of a first passive device and the second set of the alternating layers is part of a second passive device;
a first set of contact structures associated with the first set of the alternating layers; and
a second set of contact structures associated with the second set of the alternating layers, the layers of conductive material in the first set of the alternating layers are connected to one another in parallel or serially by the first set of contact structures and the at least one upper metal layer, and the layers of conductive material in the second set of the alternating layers are connected to one another in parallel or serially by the second set of contact structures and the at least one upper metal layer, separate from the first set of the alternating layers, wherein:
the first set of the alternating layers are connected to one another in parallel; and
the layers of conductive material in the first set of the alternating layers are plates of a capacitor as the first passive device;
the second set of the alternating layers are connected to one another serially; and
the layers of conductive material in the second set of the alternating layers are resistive components of a resistor as the second passive device.
2. The passive device of claim 1 , further comprising:
at least one insulation-filled slit or insulation-filled hole which extends vertically within the stack, the conductive material comprises metal silicide; and
the dielectric material comprises at least one of oxide, nitride or a combination of oxide and nitride.
3. The passive device of claim 1 , wherein:
the conductive material comprises heavily doped polysilicon having a doping concentration of 10^20 to 10^21 cm-3 or more; and
the dielectric material comprises at least one of oxide, nitride or a combination of oxide and nitride.