Bulb-Type Bottom Electrode Contact for Phase-Change Memory
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Solution Overview
Problem
Conventional phase-change memory devices face challenges in reducing reset current while maintaining low contact resistance between the bottom electrode contact and the switching device, as minimizing the contact area between the GST layer and the bottom electrode contact increases contact resistance between the bottom electrode contact and the switching device.
Innovation Solution
A phase-change memory device with a bottom electrode contact that has a bulb-type sidewall, featuring a larger diameter at the lower portion and a smaller diameter at the upper portion, allowing for increased contact area with the switching device to reduce contact resistance while maintaining a smaller contact area with the phase-change layer to minimize reset current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the contact area between the GST layer and the bottom electrode contact is reduced to lower reset current, then the reset current is improved, but the contact area between the bottom electrode contact and the switching device is also reduced, causing contact resistance to increase
Solution Approach 1:
The bottom electrode contact is divided into two distinct contact areas: a first contact area with the switching device and a second contact area with the GST layer. This segmentation allows each contact area to be independently optimized for its specific function, resolving the contradiction between reducing reset current and maintaining low contact resistance
Solution Approach 2:
Different regions of the bottom electrode contact are given different properties: the first contact area (with the switching device) is designed with larger area to minimize contact resistance, while the second contact area (with the GST layer) is designed with smaller area to reduce reset current. This local differentiation of contact areas allows simultaneous optimization of both parameters
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively reduces contact resistance between the bottom electrode contact and the switching device, enhancing on-current performance while keeping the reset current low by optimizing the contact areas between the bottom electrode contact and both the switching device and the phase-change layer.
Implementation Method 1
A phase change layer, in which a crystal phase of the phase change layer is changed according to heat generated from a current applied thereto
Implementation Method 2
heat generated from a current applied ther_to
Data Source
AI summary
A phase-change memory device and a method of manufacturing the same, wherein the phase-change memory device includes a semiconductor substrate having a switching device, a phase-change layer formed on the semiconductor substrate having the switching device to change a phase thereof as the switching device is driven, and a bottom electrode contact in contact with the switching device through a first contact area and in contact with the phase-change layer through a second contact area, which is smaller than the first contact area.