RRAM Electrode Surface Flatness via RF PVD and Planarization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for manufacturing electrodes for resistive random access memory (RRAM) result in rough surfaces and reduced thickness due to pinholes and high oxygen content, leading to poor electrical performance, and the requirement for a flat surface is not adequately met by conventional physical vapor deposition (PVD) processes.
Innovation Solution
A method involving the formation of a conductive layer and a radio frequency physical vapor deposition (RF PVD) transition metal compound layer, with a sacrificial layer of titanium nitride or tantalum nitride, followed by a planarization process to achieve a flat and compact RF PVD transition metal compound layer with sufficient thickness, ensuring improved electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If general physical vapor deposition (PVD) is used to form the electrode, then the manufacturing process is simple, but the electrode surface becomes rough with pinholes and high oxygen content, reducing electrical performance
Solution Approach 1:
The electrode structure is segmented into multiple layers: a lower electrode layer formed by PVD and an upper electrode layer formed by RF PVD. This segmentation allows each layer to serve different functions - the lower layer provides bulk conductivity while the upper layer provides a flat, low-oxygen surface, thus resolving the contradiction between manufacturing simplicity and surface precision
Solution Approach 2:
The electrode is constructed as a composite structure combining materials deposited by different methods (PVD and RF PVD). The composite structure leverages the advantages of both deposition techniques - the simplicity of PVD for bulk formation and the superior surface quality of RF PVD for the top layer, thereby achieving both ease of manufacture and high surface precision
2Manufacturing precision
If chemical mechanical polishing is used to improve the surface flatness of the lower electrode, then the surface flatness is improved, but the thickness of the lower electrode is reduced, affecting electrical performance
Solution Approach 1:
Instead of polishing the lower electrode after formation, the invention performs preliminary action by forming an upper electrode layer with inherently flat surface through RF PVD. This preliminary action provides the required surface flatness before any subsequent processing, eliminating the need for polishing that would reduce thickness and compromise electrical performance
Solution Approach 2:
The upper electrode layer acts as a copy or replica of the desired flat surface morphology. By forming this upper layer through RF PVD which naturally produces flat surfaces, the invention copies the ideal surface geometry onto the electrode structure without materially removing or thinning the lower electrode layer, thus preserving electrical performance
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
The method results in a lower electrode with a flat and compact surface and sufficient thickness, enhancing the electrical performance of RRAM devices by reducing pinholes and oxygen content, thereby improving the overall performance of the memory device.
Implementation Method 1
An RF PVD transition metal compound layer is formed on the conductive layer by using a RF PVD
Implementation Method 2
a planarization process is performed to remove the sacrificial layer and a portion of the RF PVD transition metal compound layer underlying the sacrificial layer
Data Source
AI summary
A method for manufacturing an electrode including the following steps is provided. A conductive layer is formed on a base material. A radio frequency physical vapor deposition (RF PVD) transition metal compound layer is formed on the conductive layer by using a RF PVD. A sacrificial layer is formed on the RF PVD transition metal compound layer. A planarization process is performed to remove the sacrificial layer and a portion of the RF PVD transition metal compound layer.