Semiconductor Charge Storage Region with Diffusion Barrier
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Solution Overview
Problem
Semiconductor memory devices face challenges in effectively storing electric charge due to poor performance of charge storage films, which can lead to inadequate charge retention and potential diffusion of metal atoms from these films, affecting the integrity of the memory cells.
Innovation Solution
The semiconductor device incorporates a charge storage region with a molybdenum (Mo) layer as the first charge storage film and a polysilicon layer as the second charge storage film, with an intermediate insulating film to prevent diffusion and enhance electron trapping efficiency, while also considering the thickness and in-plane concentration of Mo atoms to optimize performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a charge storage film is used to store electric charge, then charge storage function is achieved, but metal atom diffusion occurs and charge retention becomes inadequate
Solution Approach 1:
An intermediate insulating film is introduced between the charge storage film and the blocking insulating film. This intermediate layer acts as a barrier that prevents metal atoms from the charge storage film from diffusing into the blocking insulating film, thereby eliminating the harmful diffusion effect while preserving the charge storage function.
Solution Approach 2:
The patent uses a composite structure consisting of multiple layers with different material properties: a charge storage film (polysilicon or doped semiconductor), an intermediate insulating film (silicon oxide or silicon nitride), and a blocking insulating film. This composite structure combines the charge storage capability of the semiconductor material with the diffusion barrier properties of the insulating materials.
2Reliability
If charge storage film performance is poor, then charge retention is inadequate, but adding more layers increases device complexity
Solution Approach 1:
The insulating film is segmented into two distinct functional layers: an intermediate insulating film directly adjacent to the charge storage film for diffusion prevention, and a blocking insulating film for electrical isolation. This segmentation allows each layer to be optimized for its specific function, improving charge retention without excessive complexity.
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 configuration allows for improved charge storage and retention, preventing metal atom diffusion and enhancing the threshold voltage variation of memory cells, thereby ensuring effective electric charge storage and maintaining the integrity of the charge storage region.
Implementation Method 1
an intermediate insulating film to prevent diffusion and enhance electron trapping efficiency
Implementation Method 2
enhance electron trapping efficiency
Data Source
AI summary
According to one embodiment, a semiconductor device includes a substrate, a plurality of insulating films and a plurality of electrode films provided alternately on the substrate. The semiconductor device further includes a first insulating film, a first charge storage film, a third insulating film, a second charge storage film, a second insulating film, and a first semiconductor film that are sequentially provided along at least one side surface of each of the electrode films. The first charge storage film includes either (i) molybdenum, or (ii) titanium and nitrogen, and the second charge storage film includes a semiconductor film.