Semiconductor Film Gate Insulation Short Circuit Prevention
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Solution Overview
Problem
In semiconductor device manufacturing, the thinning of gate insulating films in the end portions of channel regions can lead to short circuits and leakage currents due to insufficient coverage, affecting transistor characteristics.
Innovation Solution
A semiconductor device structure where a semiconductor film is provided continuously over a substrate, with conductive films placed over the semiconductor film and gate insulating film, and impurity regions are formed to prevent short circuits and leakage currents by ensuring adequate coverage and alignment, using a method that includes forming impurity regions with specific conductivity types and concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gate insulating film is thinned in the end portions of channel regions, then transistor characteristics can be improved, but short circuits and leakage currents occur due to insufficient coverage
Solution Approach 1:
The patent applies preliminary action by forming a protective film over the gate insulating film before thinning operations. This protective layer ensures that even when the gate insulating film is thinned in the end portions, the semiconductor film remains protected from direct contact with the gate electrode, preventing short circuits while allowing the desired thinning for improved transistor characteristics
Solution Approach 2:
The patent introduces a protective film as an intermediary layer between the gate insulating film and the semiconductor film. This intermediary layer maintains the necessary insulation even when the gate insulating film thickness is reduced, enabling both improved transistor characteristics and prevention of short circuits
2Reliability
If the gate insulating film thickness is reduced, then transistor performance can be enhanced, but leakage currents increase due to breakage in end portions
Solution Approach 1:
The protective film is formed in advance before the gate insulating film thinning process. This preliminary protective layer prevents leakage currents by maintaining continuous insulation at the end portions where the gate insulating film is thinned, while still allowing the performance enhancements from reduced thickness in the channel region
Solution Approach 2:
The protective film acts as a cushioning layer that prevents the harmful effect of leakage currents before they can occur. By being in place before the thinning operation, it ensures that even when the gate insulating film is compromised at the edges, the semiconductor film remains protected from electrical leakage
3Ease of manufacture
If island-shaped semiconductor films are formed selectively, then transistor structure can be created, but steps at channel region ends cause gate insulating film disconnection
Solution Approach 1:
The protective film serves as an intermediary that bridges the gap caused by steps at the channel region ends. When island-shaped semiconductor films are formed, steps occur at the boundaries, but the protective film maintains continuous coverage over these stepped regions, preventing disconnection of the gate insulating film while allowing easy formation of the transistor structure
Solution Approach 2:
The protective film is formed as a thin, flexible layer that can conform to the stepped topography created by island-shaped semiconductor films. This thin film approach maintains continuity over the steps without adding significant complexity to the manufacturing process, preventing gate insulating film disconnection while preserving the desired transistor structure
Data Source
AI summary
The present invention provides a semiconductor device which suppresses a short circuit and a leakage current between a semiconductor film and a gate electrode generated by a break or thin thickness of a gate insulating film in an end portion of a channel region of the semiconductor film, and the manufacturing method of the semiconductor device. Plural thin film transistors which each have semiconductor film provided over a substrate continuously, conductive films provided over the semiconductor film through a gate insulating film, source and drain regions provided in the semiconductor film which are not overlapped with the conductive films, and channel regions provided in the semiconductor film existing under the conductive films and between the source and drain regions. And impurity regions provided in the semiconductor film which is not overlapped with the conductive film and provided adjacent to the source and drain regions. Further, the conductive films are provided over the channel regions and regions of the semiconductor film which are provided adjacent to the channel regions.