Gate Electrode Barrier Layer for Non-Volatile Memory Work Function Stability
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Solution Overview
Problem
Conventional non-volatile memory devices experience increased erase time and degraded data retention due to back-tunneling of electrons through the blocking layer, which is exacerbated by variations in the work function of the gate electrode during heat treatment processes.
Innovation Solution
Incorporating a barrier layer, such as metal silicon nitride, on the conductive layer to reduce the effects of heat treatment and stabilize the work function, thereby minimizing back-tunneling and improving erase time and data retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive layer with high work function (e.g., metal nitride or metal oxide) is used to reduce back-tunneling, then electron back-tunneling through the blocking layer is reduced, but the work function varies during heat treatment processes, degrading device reliability
Solution Approach 1:
The gate electrode is formed as a composite structure with a first conductive layer (metal nitride or metal oxide with high work function) and a second conductive layer (different material) deposited thereon. This composite structure combines the high work function property for reducing back-tunneling with the stability of the second material against heat treatment, preventing work function variation during manufacturing processes.
Solution Approach 2:
The gate electrode is segmented into multiple layers with distinct functions: the first conductive layer provides high work function to reduce electron back-tunneling, while the second conductive layer provides thermal stability. This segmentation allows each layer to independently fulfill its specific function without interfering with the other.
2Reliability
If conventional conductive materials are used in the gate electrode, then the device structure is simpler, but electron back-tunneling through the blocking layer increases during erasing operations
Solution Approach 1:
The gate electrode uses a composite structure where the first conductive layer (metal nitride or metal oxide) provides high work function to suppress electron back-tunneling during erasing operations. This composite approach targets the specific erasing performance issue without requiring complete structural redesign.
Solution Approach 2:
The work function parameter of the gate electrode is optimized by selecting materials with specifically high work function values (metal nitride or metal oxide). This parameter change directly addresses the back-tunneling issue during erasing operations, improving erase performance through material property selection.
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 barrier layer effectively reduces the variation in the work function of the conductive layer, shortening erase time and enhancing the data retention and reliability of the non-volatile memory device.
Implementation Method 1
the barrier layer reducing the effects of heat treatment on the conductive layer
Implementation Method 2
the barrier layer reducing the effects of heat treatment on the conductive layer... effectively reduces the variation in the work function of the conductive layer, shortening erase time and enhancing the data retention
Data Source
AI summary
A non-volatile memory device includes a tunnel insulating layer pattern on a channel region of a substrate, a charge trapping layer pattern on the tunnel insulating layer pattern, a blocking layer pattern on the charge trapping layer pattern, and a gate electrode including a conductive layer pattern on the blocking layer pattern and a barrier layer pattern on the conductive layer pattern. The conductive layer pattern includes a metal.