Oxide Semiconductor Film Stabilization via Halogen and Oxygen Doping
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Solution Overview
Problem
The electric conductivity of oxide semiconductors varies due to hydrogen or water entering the semiconductor during manufacturing, leading to unstable electric characteristics in transistors.
Innovation Solution
A method involving dehydration or dehydrogenation by heat treatment, halogen doping, and oxygen doping is employed to stabilize the oxide semiconductor film, ensuring it has stable electric characteristics and high reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat treatment is performed to remove hydrogen from oxide semiconductor film, then electric characteristic stability is improved, but manufacturing process complexity increases
Solution Approach 1:
The patent applies preliminary action by performing dehydration and dehydrogenation heat treatment on the oxide semiconductor film before transistor formation. This removes hydrogen and water from the film in advance, preventing future electric characteristic variations and eliminating the need for subsequent stability correction steps.
Solution Approach 2:
The patent uses parameter changes by controlling heat treatment temperature (typically 400-700°C) and atmosphere (oxygen, nitrogen, or vacuum) to optimize hydrogen removal while preventing film degradation. These parameter optimizations achieve stability improvement without requiring excessively complex multi-step processes.
2Reliability
If multiple doping treatments (halogen and oxygen) are applied to stabilize oxide semiconductor, then electric characteristic stability is improved, but manufacturing time increases
Solution Approach 1:
The patent merges multiple stabilization functions into an integrated process sequence where halogen doping and oxygen doping treatments are combined with heat treatment steps. The halogen doping introduces chlorine or fluorine atoms to passivate hydrogen, while oxygen doping restores oxygen vacancies, and these are coordinated with thermal processing to achieve comprehensive stabilization without requiring separate dedicated steps for each treatment.
Solution Approach 2:
The patent maintains continuity of useful action by performing doping treatments and heat treatment in a continuous or closely sequenced manner without interrupting the manufacturing flow. The oxide semiconductor film undergoes successive treatments in an uninterrupted process, maximizing efficiency while achieving thorough stabilization.
3Manufacturing precision
If dehydration and dehydrogenation treatments are performed, then threshold voltage variation is reduced, but manufacturing cost increases
Solution Approach 1:
The patent applies self-service by using the oxide semiconductor film's own structural characteristics to achieve stabilization. The heat treatment utilizes the film's inherent oxygen storage capacity and thermal stability to drive off hydrogen and water, while subsequent oxygen doping replenishes oxygen using the film's own oxygen affinity, reducing reliance on external complex processing equipment.
Solution Approach 2:
The patent employs inert atmosphere heat treatment (using nitrogen, vacuum, or oxygen atmosphere) to prevent contamination during hydrogen removal. This controlled environment approach achieves precise threshold voltage control while avoiding the need for expensive ultra-high vacuum equipment or complex gas handling systems, balancing precision with cost-effectiveness.
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 method effectively removes hydrogen, stabilizes the oxide semiconductor film, and reduces variations in threshold voltage, resulting in a highly reliable transistor with stable electrical characteristics.
Implementation Method 1
performing first heat treatment on the oxide semiconductor film so that a hydrogen atom in the oxide semiconductor film is removed
Implementation Method 2
performing halogen doping treatment on the first insulating film so that the first insulating film is supplied with a halogen atom
Implementation Method 3
performing oxygen doping treatment on the oxide semiconductor film from which the hydrogen atom is removed so that the oxide semiconductor film is supplied with an oxygen atom
Data Source
AI summary
The method for manufacturing the semiconductor device is as follows: forming a gate electrode; forming a first insulating film over the gate electrode; performing halogen doping treatment on the first insulating film so that the first insulating film is supplied with a halogen atom; forming an oxide semiconductor film over the first insulating film so as to overlap with the gate electrode; performing heat treatment on the oxide semiconductor film so that a hydrogen atom is removed in the oxide semiconductor film; performing oxygen doping treatment on the oxide semiconductor film from which the hydrogen atom is removed so that the oxide semiconductor film is supplied with an oxygen atom; performing heat treatment on the oxide semiconductor film to which the oxygen atom is supplied; forming a source electrode and a drain electrode on and in contact with the oxide semiconductor film; forming a second insulating film.