Semiconductor memory device and phase change memory device
A phase change memory (PCM) device includes a substrate, bottom electrodes disposed in the substrate, a first dielectric layer disposed on the substrate, second dielectric layers, third dielectric layers, cup-shaped thermal electrodes, top electrodes, and PC material spacers. In the PCM device, each cup-shaped thermal electrode contacts with each bottom electrode. Second and third dielectric layers are disposed over the substrate in different directions, wherein each of the second and third dielectric layers covers a portion of the area surrounded by each cup-shaped thermal electrode, and the third dielectric layers overlay the second dielectric layers. The top electrodes are disposed on the third dielectric layers, wherein a plurality of stacked structure composed of the third dielectric layers and the top electrodes are formed thereon. The PC material spacers are formed on the sidewalls of each stacked structure and physically and electrically contact the cup-shaped thermal electrodes and the top electrodes.
1. A phase change memory (PCM) device, comprising:
a substrate;
a plurality of bottom electrodes, formed in the substrate;
a first dielectric layer, disposed over the substrate;
a plurality of cup-shaped thermal electrodes, disposed in the first dielectric layer, wherein each bottom of the cup-shaped thermal electrodes contacts one of the bottom electrodes;
a plurality of second dielectric layers, disposed over the substrate in a first direction, wherein each of the second dielectric layers covers a portion of the area surrounded by each of the cup-shaped thermal electrodes;
a plurality of third dielectric layers, disposed over the substrate in a second direction, wherein each of the third dielectric layers covers a portion of the area surrounded by each of the cup-shaped thermal electrodes, and overlays the second dielectric layers;
a plurality of top electrodes, disposed over the third dielectric layers so that a plurality of stacked structures including the third dielectric layers and the top electrodes are formed over the substrate; and
a plurality of phase change (PC) material spacers, disposed on sidewalls of the stacked structures, wherein the PC material spacers physically and electrically contact the cup-shaped thermal electrodes and the top electrodes.
2. The PCM device as claimed in claim 1 , wherein the material of the cup-shaped thermal electrodes comprises transition or refractory metal nitrides, W, nitrided metal silicide, polysilicon, amorphous silicon or a metal silicide.
3. The PCM device as claimed in claim 1 , wherein the material of the top electrodes comprise TiW, transition or refractory metal nitrides, Al, Cu/TaN, nitrided metal silicide, polysilicon, amorphous silicon or a metal silicide.
4. The PCM device as claimed in claim 1 , wherein the first dielectric layers and the third dielectric layers are the same material other than silicon dioxide, and the second dielectric layers are a dielectric material with an etching selectivity with the first and third dielectric layers.
5. A semiconductor memory device, comprising:
a substrate;
a plurality of bottom electrodes, formed in the substrate;
a first dielectric layer, disposed on the substrate;
a plurality of cup-shaped electrodes, disposed in the first dielectric layer, wherein each bottom of the cup-shaped electrodes contacts one of the bottom electrodes;
a plurality of second dielectric layers, disposed over the substrate in a first direction, wherein each of the second dielectric layers covers a portion of the area surrounded by each of the cup-shaped electrodes;
a plurality of third dielectric layers, disposed over the substrate in a second direction, wherein the third dielectric layers covers a portion of the area surrounded by the cup-shaped electrodes, and overlays the second dielectric layers;
a plurality of top electrodes, disposed over the third dielectric layers, wherein a plurality of stacked structure composed the third dielectric layers and the top electrodes is formed;
a plurality of conductive spacers, disposed on sidewall of the stacked structure, wherein the conductive spacers physically and electrically contact the cup-shaped electrodes and top electrodes; and
a non-volatile memory unit cell, formed between each of the conductive spacers and each of the cup-shaped electrodes.
6. The semiconductor memory device as claimed in claim 5 , wherein the material of the cup-shaped electrodes comprises TiW, transition or refractory metal nitrides, Al, Cu/TaN, polysilicon, amorphous silicon, PC materials, nitrided metal silicide or a metal silicide.
7. The semiconductor memory device as claimed in claim 5 , wherein the material of the conductive material spacers comprises TiW, transition or refractory metal nitrides, Al, Cu/TaN, polysilicon, amorphous silicon, PC materials, nitrided metal silicide or a metal silicide.
8. The semiconductor memory device as claimed in claim 5 , wherein the first and third dielectric layers are the same material other than silicon dioxide, and the second dielectric layers are a dielectric material with an etching selectivity with the first and third dielectric layers.
9. The semiconductor memory device as claimed in claim 5 , wherein the non-volatile memory unit cell comprises an MTJ unit cell of a MRAM, an anti-fuse cell of a Mask ROM or a PROM, or a unit cell of a RRAM.