Nitrogen-Doped Insulating Oxide Layers for NAND Memory Threshold Voltage Uniformity
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Solution Overview
Problem
In three-dimensionally stacked NAND-type semiconductor memory devices, variations in threshold voltage and electric field distribution occur due to the shape of lateral surfaces, leading to inconsistent memory cell performance and increased operational voltage requirements.
Innovation Solution
Incorporating nitrogen-doped insulating oxide layers between electrode layers and a semiconductor layer, with nitrogen atoms distributed around the interface to reduce curvature radii and electric fringe fields, thereby improving the uniformity of threshold voltage and reducing parasitic capacitance and leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional insulating oxide layers are used between electrode layers and semiconductor layer, then the device structure is simple and manufacturing is easier, but threshold voltage variations increase and memory cell performance becomes inconsistent
Solution Approach 1:
The patent applies local quality by creating a nitrogen-doped region specifically at the interface between the first insulating oxide layer and semiconductor layer, while the bulk of the insulating layers remains conventional. This localized modification of the interface region provides improved threshold voltage uniformity without requiring complete restructuring of the entire insulating layer system, thus resolving the contradiction between manufacturing precision and device complexity.
Solution Approach 2:
The patent changes the chemical composition parameter of the insulating oxide layer by introducing nitrogen atoms at the interface region. This parameter change (adding nitrogen) modifies the electrical properties at the critical interface, reducing threshold voltage variations and improving memory cell performance consistency without fundamentally changing the overall device architecture.
2Use of energy by moving object
If lateral surfaces have large curvature radii, then manufacturing is easier, but electric fringe fields increase leading to higher operational voltage requirements
Solution Approach 1:
The nitrogen-doped insulating oxide layer acts as an intermediary at the interface between the electrode layers and semiconductor layer. This intermediary layer modifies the electric field distribution at the lateral surfaces, reducing fringe fields and allowing for lower operational voltages without requiring precise control of lateral surface curvature, thus resolving the contradiction between energy use and manufacturing precision.
3Reliability
If standard insulating oxide layers are used, then device complexity is low, but parasitic capacitance and leakage currents increase
Solution Approach 1:
The patent changes the compositional parameter of the insulating oxide layer by incorporating nitrogen atoms at the interface region. This parameter change reduces parasitic capacitance and leakage currents, improving memory cell reliability. The modification is localized to the interface region, so the overall device complexity remains manageable, resolving the contradiction between reliability and device 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 approach enhances the controllability of memory cells, reduces threshold voltage variations, and improves data writing efficiency by minimizing the frequency of read operations, while also mitigating electric field stress and enhancing the reliability of memory cells.
Implementation Method 1
Incorporating nitrogen-doped insulating oxide layers between electrode layers and a semiconductor layer, with nitrogen atoms distributed around the interface
Implementation Method 2
nitrogen atoms distributed around an interface between the first insulating oxide layer and the second insulating oxide layer
Data Source
AI summary
A semiconductor memory device includes a first electrode layer; a second electrode layer provided above the first electrode layer; a first insulating oxide layer provided between the first and second electrode layers; a semiconductor layer extending through the first electrode layer, the first insulating oxide layer and the second electrode layer that are stacked in the first direction; and a second insulating oxide layer extending in the first direction between the semiconductor layer and the first insulating oxide layer, the second insulating oxide layer being in contact with the first insulating oxide layer. At least one of the first insulating oxide layer and the second insulating oxide layer includes nitrogen atoms. The nitrogen atoms are distributed around an interface between the first insulating oxide layer and the second insulating oxide layer, or distributed in the vicinity of the interface.