Getter Layer for Memory Device Hydrogen Contamination
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Solution Overview
Problem
The quality of oxide-nitride-oxide (ONO) structures in non-volatile memory devices, such as EEPROMs, is critical for performance but is often compromised by contamination, particularly by hydrogen atoms that can degrade retention and stability, leading to adverse effects during programming and reliability tests.
Innovation Solution
A getter layer comprising a multi-stack structure with a titanium-based first layer and a tantalum nitride-based second layer is formed over the memory device's electrode to immobilize and block hydrogen and other chemical species, preventing them from entering the ONO layer and thereby enhancing the device's performance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional memory device structure is used without additional protective layers, then the device complexity is low, but the ONO structure becomes contaminated by hydrogen atoms leading to degraded retention and stability
Solution Approach 1:
A getter layer comprising titanium and tantalum nitride is introduced as an intermediary layer between the ONO structure and the surrounding environment. This getter layer acts as a mediator that selectively absorbs hydrogen atoms and other chemical species, preventing them from reaching and contaminating the ONO structure, thereby improving retention and stability without fundamentally changing the core memory device architecture
Solution Approach 2:
The getter layer is formed as a composite structure combining titanium and tantalum nitride materials. This composite material approach leverages the complementary properties of both materials: titanium provides hydrogen absorption capability while tantalum nitride provides chemical stability and barrier properties, together creating an effective protection system for the ONO structure
2Manufacturing precision
If the ONO structure is exposed to hydrogen atoms during fabrication and operation, then the manufacturing process is simple, but the chemical purity of the ONO structure degrades leading to adverse effects during programming and reliability tests
Solution Approach 1:
The getter layer is formed prior to subsequent fabrication steps that may expose the device to hydrogen-containing environments. By establishing this protective barrier in advance, the ONO structure is pre-protected from hydrogen contamination during ion implantation, annealing, and other processing steps, ensuring chemical purity is maintained throughout the manufacturing process
Solution Approach 2:
The getter layer serves as a protective intermediary between the ONO structure and the fabrication environment. It selectively interacts with hydrogen atoms and other chemical species, absorbing or blocking them before they can reach the ONO structure, thereby maintaining chemical purity without requiring complex in-situ protection methods during manufacturing
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 getter layer effectively reduces contamination within the memory device, improving retention and stability by preventing hydrogen atoms from affecting the ONO structure, thus enhancing the overall performance and reliability of the memory device.
Implementation Method 1
the getter layer is configured to collect (or immobilize) chemical species that may enter the memory device during subsequent fabrication/testing processes
Implementation Method 2
forming a getter layer over the conductive layer, wherein the getter layer includes a first layer that is formed of titanium and a second layer overlying the first layer that is formed of tantalum nitride
Data Source
AI summary
A method includes providing a semiconductor device disposed on a substrate, wherein the semiconductor device includes a semiconductor device feature, forming a conductive layer over the substrate such that the conductive layer is electrically coupled to the semiconductor device feature, forming a getter layer over the conductive layer, wherein the getter layer includes a first layer that is formed of titanium and a second layer overlying the first layer that is formed of tantalum nitride, and forming an interconnect layer over the getter layer such that the interconnect layer is electrically coupled to the semiconductor device feature.