Semiconductor Storage Element Using Self-Organized Quantum Dots
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Solution Overview
Problem
Existing methods for manufacturing single-electron memory elements face challenges in achieving uniformity and mass production due to reliance on complex processes like electron beam lithography and insufficient process controllability, making stable and cost-effective production difficult.
Innovation Solution
A semiconductor storage element is fabricated using a semiconductor layer with quantum dots as an electric charge storage layer, sandwiched by impurity diffusion layers and controlled by a gate electrode, with a manufacturing method involving sidewall mask processing to form crisscross patterns on a substrate, allowing for precise control of quantum dot size and arrangement without relying on high-resolution lithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electron beam lithography is used to manufacture single-electron memory elements, then quantum dot size and arrangement can be precisely controlled, but manufacturing complexity increases and mass production becomes difficult
Solution Approach 1:
The patent introduces a self-organizing mechanism as an intermediary between conventional lithography and quantum dot formation. By using a periodic potential field (created by intersecting line patterns) to guide atom migration, the system achieves precise quantum dot positioning without requiring high-resolution electron beam lithography. The self-organization process mediates the transformation from simple line patterns to precisely arranged quantum dots.
Solution Approach 2:
The patent employs self-organization of atoms under a periodic potential field to automatically form quantum dots with precise spacing. The system uses its own internal dynamics (atom migration and aggregation) to achieve the desired structure, eliminating the need for complex external lithography processes. The quantum dots self-assemble at predetermined intervals based on the intersecting line pattern geometry.
2Productivity
If conventional manufacturing methods are used, then mass production may be achieved, but element uniformity is insufficient and stable production is difficult
Solution Approach 1:
The patent changes the fundamental parameter of quantum dot formation from top-down lithographic patterning to bottom-up self-organization. By controlling the periodic potential field parameters (line pattern width, spacing, and intersection geometry) and thermal processing conditions, the system achieves uniform quantum dots with precise spacing that can be manufactured at scale using conventional semiconductor fabrication techniques.
3Temperature
If irregularities of polysilicon film are utilized to form quantum dots, then room temperature operation is achieved, but process controllability is insufficient and peripheral circuits become large
Solution Approach 1:
The patent applies local quality by creating a periodic potential field with specific spatial characteristics that guide atom migration to predetermined locations. The intersecting line patterns generate local energy minima at regular intervals, causing quantum dots to form only at these specific locations with controlled size and spacing. This local structuring of the potential field provides the controllability that was missing in previous approaches.
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 enables mass-producible semiconductor storage elements with stable uniformity and high throughput, allowing for the production of quantum dots that operate at room temperature with improved controllability and reduced manufacturing costs.
Implementation Method 1
a quantum dot forming an electric charge storage layer formed on the semiconductor layer through a first insulating film serving as a tunnel insulating film
Implementation Method 2
an impurity diffusion layer formed in a surface layer of the semiconductor layer so as to sandwich the quantum dot therebetween
Data Source
AI summary
A semiconductor storage element includes: a semiconductor layer constituted of a line pattern with a predetermined width formed on a substrate; a quantum dot forming an electric charge storage layer formed on the semiconductor layer through a first insulating film serving as a tunnel insulating film; an impurity diffusion layer formed in a surface layer of the semiconductor layer so as to sandwich the quantum dot therebetween; and a control electrode formed on the quantum dot through a second insulating film.