Alumina-Covered Gate Electrode for Oxide Semiconductor Yield
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Solution Overview
Problem
Miniaturization of transistors leads to reduced yield and stability issues due to electrical failures and impurity infiltration, which affects their on-state characteristics and reliability.
Innovation Solution
A semiconductor device structure with an oxide semiconductor film, a gate insulating film, and a gate electrode layer covered by an aluminum oxide film, along with low-resistance regions formed using a dopant, enhances the on-state characteristics and prevents electrical failures by shielding impurities and moisture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If transistors are miniaturized to achieve high-speed operation and low power consumption, then transistor performance is improved, but manufacturing yield and reliability deteriorate due to electrical failures and impurity infiltration
Solution Approach 1:
An aluminum oxide film is introduced as an intermediary protective layer between the gate electrode layer and the external environment. This film acts as a barrier that prevents impurity infiltration while allowing the miniaturized transistor to maintain its high-speed performance without suffering from reliability degradation due to contamination
Solution Approach 2:
The aluminum oxide film creates an inert protective environment around the gate electrode layer, shielding it from moisture and impurities in the external environment. This passive protection mechanism allows miniaturized transistors to operate reliably without direct exposure to harmful contaminants
2Productivity
If transistors are miniaturized to improve integration density, then device integration is enhanced, but manufacturing yield declines due to increased electrical failures
Solution Approach 1:
The aluminum oxide film serves as a protective intermediary that reduces electrical failures in miniaturized transistors. By preventing impurity entry and moisture exposure, it maintains manufacturing yield even as transistors are scaled down to achieve higher integration densities
Solution Approach 2:
The aluminum oxide film is formed on the gate electrode layer before final transistor assembly and testing. This preliminary protective action prevents impurity infiltration during subsequent manufacturing steps, ensuring high manufacturing yield for miniaturized devices
3Reliability
If the gate electrode layer is exposed to improve electrical contact, then conductivity is enhanced, but impurity infiltration and short circuits increase
Solution Approach 1:
The aluminum oxide film creates an inert barrier that protects the gate electrode layer from impurity infiltration while maintaining the necessary electrical contact quality. The film's insulating properties prevent short circuits while its protective function blocks harmful contaminants
4Ease of manufacture
If oxide semiconductor film oxygen is released to simplify structure, then manufacturing is easier, but electrical characteristics become unstable
Solution Approach 1:
The aluminum oxide film acts as a protective intermediary that prevents external moisture and impurities from causing oxygen release from the oxide semiconductor film. This maintains stable electrical characteristics while allowing the use of oxide semiconductors with simpler oxygen supply structures
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 enables high-yield manufacturing of miniaturized transistors with improved electrical characteristics and reliability, ensuring stable operation and high-speed performance.
Implementation Method 1
The insulating film including an aluminum oxide film has a superior shielding effect (blocking effect), which is not permeable to either oxygen or impurities such as hydrogen or moisture.
Implementation Method 2
Oxygen (which includes at least one of an oxygen radical, an oxygen atom, and an oxygen ion) may be introduced to the oxide semiconductor film to supply the oxygen to the oxide semiconductor film.
Data Source
AI summary
A miniaturized transistor having excellent electrical characteristics is provided with high yield. Further, a semiconductor device including the transistor and having high performance and high reliability is manufactured with high productivity. In a semiconductor device including a transistor in which an oxide semiconductor film including a channel formation region and low-resistance regions between which the channel formation region is sandwiched, a gate insulating film, and a gate electrode layer whose top surface and side surface are covered with an insulating film including an aluminum oxide film are stacked, a source electrode layer and a drain electrode layer are in contact with part of the oxide semiconductor film and the top surface and a side surface of the insulating film including an aluminum oxide film.