Memory Cell Access Assembly With Domed Caps for Low Contact Resistance
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Solution Overview
Problem
Current memory technologies face challenges in developing improved transistors and memory architectures that effectively manage oxidation of conductive materials and reduce contact resistance at interfaces, leading to increased resistance and potential mechanical strain.
Innovation Solution
The use of domed metal-containing caps over and under the channel material in access transistors, comprising materials like tungsten, molybdenum, and conductive oxides, which alleviate oxidation issues and reduce contact resistance by providing additional surface area and mechanical robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conductive materials are used in memory cells, then electrical conductivity is achieved, but oxidation occurs leading to increased resistance
Solution Approach 1:
A conductive oxide layer is introduced as an intermediary between the conductive material and the domed cap. This intermediate layer prevents direct oxidation of the conductive material while maintaining electrical conductivity, thereby resolving the contradiction between achieving conductivity and preventing oxidation-induced resistance increase
Solution Approach 2:
The structure employs a composite design combining conductive material, conductive oxide, and domed cap materials (such as tungsten, molybdenum, or cobalt). This composite approach allows each layer to perform its specific function: the conductive material provides conductivity, the oxide layer prevents further oxidation, and the domed cap provides mechanical protection, collectively preventing oxidation while maintaining low resistance
2Productivity
If contact area between conductive materials is reduced, then device density is improved, but contact resistance increases
Solution Approach 1:
The domed cap structure with its curved, spherical surface increases the effective contact area with the conductive oxide layer compared to a flat surface. This curvature allows for better mechanical contact and reduced contact resistance while maintaining compact device dimensions, thus resolving the contradiction between device density and contact resistance
3Reliability
If conductive materials are subjected to mechanical stress, then device functionality is maintained, but mechanical strain leads to increased resistance
Solution Approach 1:
The composite structure of conductive material, conductive oxide, and domed cap creates a mechanically robust assembly. The domed cap acts as a protective shell that absorbs and distributes mechanical stress, preventing direct transmission of strain to the conductive material. This protects the conductive pathway from mechanical-induced resistance changes while maintaining device functionality under stress
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 domed caps effectively prevent oxidation of conductive materials, reduce contact resistance, and enhance mechanical stability, improving the performance and reliability of memory cells in integrated assemblies.
Implementation Method 1
The domed caps effectively prevent oxidation of conductive materials
Implementation Method 2
reduce contact resistance by providing additional surface area
Data Source
AI summary
Some embodiments include an integrated assembly having an access device between a storage element and a conductive structure. The access device has channel material which includes semiconductor material. The channel material has a first end and an opposing second end, and has a side extending from the first end to the second end. The first end is adjacent the conductive structure, and the second end is adjacent the storage element. Conductive gate material is adjacent the side of the channel material. A first domed metal-containing cap is over the conductive structure and under the channel material and/or a second domed metal-containing cap is over the channel material and under the storage element. Some embodiments include methods of forming integrated assemblies.