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US 8,618,524 B2Granted
Phase change memory with various grain sizes
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsChun-Sheng Liang, Tzyh-Cheang Lee, Fu-Liang Yang
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Abstract
A memory device includes a phase change element, which further includes a first phase change layer having a first grain size; and a second phase change layer over the first phase change layer. The first and the second phase change layers are depth-wise regions of the phase change element. The second phase change layer has a second average grain size different from the first average grain size.
Claims18
A memory device comprising:
- a substrate;
- a phase change element comprising:
- a heater over the substrate;
- and
- a phase change layer over the heater, wherein an upper portion of the phase change layer has greater average grain sizes than a lower portion of the phase change layer;
- an amorphous phase change region between and physically separating the heater from the lower portion of the phase change layer;
- and
- a conductive feature over the phase change layer.
5 more elements
A memory device comprising:
- a substrate;
- a first conductor over the substrate;
- a second conductor over the substrate;
- and
- a phase change element between the first and the second conductors, wherein the phase change element comprises:
- a first sub layer adjoining the first conductor, wherein the first sub layer has a first average grain size;
- a second sub layer adjoining the second conductor and comprising a portion overlapping the first sub layer, wherein the second sub layer has a second average grain size greater than the first average grain size, and wherein a ratio of the second average grain size to the first average grain size is greater than about two, and wherein the first sub layer has a horizontal dimension smaller than a respective horizontal dimension of the second sub layer;
- and
- a transition layer between the first and the second sub layers and having gradually increased average grain sizes, wherein upper portions of the transition layer have greater average grain sizes than lower portions of the transition layer.
6 more elements
A memory device comprising:
- a semiconductor substrate;
- a conductive feature over the semiconductor substrate;
- a dielectric layer over the conductive feature;
- a trench in the dielectric layer, wherein the conductive feature has at least a portion exposed through the trench;
- and
- a phase change element comprising:
- a phase change layer having a first portion extending into the trench, wherein the first portion has a first average grain size;
- a middle portion over the first portion, wherein the middle portion has gradually increased average grain sizes;
- and
- a second portion over the dielectric layer and the middle portion, wherein the second portion has a second average grain size greater than about two times the first average grain size.
7 more elements
Dependencies are inferred from the claim text.