Oxide Semiconductor Memory Transistor Structure for Low Off-Leakage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor storage devices face operational malfunctions due to high off-leakage current caused by electron carriers generated from oxygen deficiency in the channel layer of memory transistors.
Innovation Solution
The semiconductor device incorporates a memory transistor with an oxide semiconductor layer, a charge storage film, and an electric conductor extending from the source or drain electrode. The trap operation traps electron carriers in the charge storage film, reducing off-leakage current and preventing operational malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional semiconductor device is used, then the device structure is simple, but high off-leakage current occurs due to electron carriers generated from oxygen deficiency in the channel layer
Solution Approach 1:
An electric conductor extending from the source or drain electrode toward the gate electrode serves as an intermediary element. This conductor is surrounded by the oxide semiconductor layer and positioned to intercept electron carriers generated from oxygen deficiency, preventing them from reaching the channel and causing leakage current. The intermediary structure directly addresses the reliability issue without fundamentally redesigning the entire device.
Solution Approach 2:
The harmful electron carriers generated from oxygen deficiency are extracted from the channel region by the electric conductor. The conductor acts as a trap or collection point for these carriers, removing them from the path between source and drain, thereby eliminating their harmful effect on off-leakage current while maintaining the overall device structure.
2Speed
If the channel layer is made thinner to improve switching speed, then the switching speed increases, but off-leakage current increases due to oxygen deficiency effects
Solution Approach 1:
The electric conductor positioned within the oxide semiconductor layer acts as a mediator that captures electron carriers before they can cause leakage current. This allows the channel layer to be made thinner for faster switching without the penalty of increased off-leakage current, as the conductor intercepts the harmful carriers that would otherwise result from the thinner layer's greater susceptibility to oxygen deficiency.
3Power
If oxygen deficiency is increased to improve conductivity, then the on-state current increases, but off-leakage current increases due to electron carrier generation
Solution Approach 1:
The electric conductor serves as a selective intermediary that allows beneficial effects of oxygen deficiency (improved on-state conductivity) while capturing the harmful byproduct (electron carriers that cause off-leakage). The conductor is positioned to intercept carriers without preventing the overall conductivity enhancement from oxygen deficiency, thus resolving the contradiction between on-state power and off-state reliability.
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 solution effectively decreases the off-leakage current of the memory transistor, thereby reducing operational malfunctions and extending data storage time in semiconductor storage devices.
Implementation Method 1
a charge storage film between the semiconductor layer and the electric conductor... The trap operation traps electron carriers in the charge storage film
Data Source
AI summary
A semiconductor device includes a first conductive layer extending along a first direction, a semiconductor layer extending along a second direction crossing the first direction, penetrating the first conductive layer, and including an oxide semiconductor, a first insulating layer between the first conductive layer and the semiconductor layer, a second conductive layer provided on one side of the semiconductor layer in the second direction and electrically connected thereto, a third conductive layer provided on the other side of the semiconductor layer in the second direction and electrically connected thereto, an electric conductor extending from the third conductive layer toward the second conductive layer along the semiconductor layer, and a charge storage film between the semiconductor layer and the electric conductor.