Tin Oxide Transistor Contacts With Tunneling Barrier Liners
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Tin monoxide, a p-type semiconductor material, is prone to oxidation and forms metal-induced gap states (MIGS) at its interface with metal contacts, degrading contact resistance and transistor performance in thin-film transistors.
Innovation Solution
Incorporating a tunneling dielectric barrier liner, composed of materials like alkaline-earth metal oxides or specific dielectric oxides, to prevent metal wave function penetration and act as a diffusion barrier, thereby reducing MIGS formation and optimizing electron tunneling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal contact is directly formed on tin monoxide, then electrical contact is established, but metal-induced gap states form and degrade contact resistance
Solution Approach 1:
A tunneling dielectric barrier liner is introduced as an intermediary layer between the metal contact and tin monoxide channel. This liner prevents direct metal wave function penetration into the semiconductor, thereby suppressing MIGS formation while still allowing electron tunneling for electrical contact. The liner acts as a mediator that resolves the conflict between establishing electrical contact and preventing harmful states.
Solution Approach 2:
The contact structure is formed as a composite system comprising multiple materials: the metal contact layer, the tunneling dielectric barrier liner (made from materials like alkaline-earth metal oxides or specific dielectric oxides), and the tin monoxide channel. This composite structure combines the advantages of each material to achieve both low contact resistance and suppression of metal-induced gap states.
2Ease of manufacture
If tin monoxide is exposed to oxygen environment, then processing is simplified, but oxidation occurs and degrades transistor performance
Solution Approach 1:
The tunneling dielectric barrier liner is formed on the tin monoxide surface before the metal contact is deposited. This preliminary protective action prevents oxidation of the tin monoxide during subsequent processing steps that may involve oxygen exposure, while still allowing the processing to proceed in simplified manner.
Solution Approach 2:
The tunneling dielectric barrier liner serves as a protective intermediary that shields the tin monoxide from oxygen exposure during manufacturing processes. This liner allows the device to be processed in simpler oxygen-containing environments without compromising the stability of the tin monoxide channel.
3Object-generated harmful factors
If a thick dielectric barrier is used to prevent metal penetration, then MIGS formation is suppressed, but electron tunneling is blocked and contact resistance increases
Solution Approach 1:
The thickness of the tunneling dielectric barrier liner is precisely controlled within a specific range (typically 1-5 nm). This parameter optimization allows the liner to be thick enough to suppress metal wave function penetration and MIGS formation, while remaining thin enough to permit electron tunneling for low contact resistance. The quantum tunneling probability is highly sensitive to barrier thickness, so precise control is critical.
Solution Approach 2:
The tunneling dielectric barrier liner has different functional requirements at different locations: it must provide strong barrier properties to prevent metal penetration into the tin monoxide channel, while simultaneously allowing electron tunneling for electrical contact. The local quality of the liner (its thickness and material composition) is optimized to satisfy both conflicting requirements at the metal-semiconductor interface.
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
Enhances the stability and interface quality of tin monoxide transistors, maintaining performance and reliability by preventing MIGS formation and ensuring low contact resistance.
Implementation Method 1
The tunneling dielectric barrier liner may reduce the penetration of a wave function from a metal into a semiconductor, preventing formation of metal induced gap states
Implementation Method 2
The tunneling dielectric barrier liner may act as diffusion barrier
Data Source
AI summary
Contacts that protect tin oxide semiconductor material in a thin-film transistor may be provided by forming a stack including a gate electrode, a gate dielectric, and an active layer comprising a tin oxide semiconductor material over a dielectric material layer that overlies a substrate; forming an assembly of a source electrode, a drain electrode, and an insulating layer extending between the source electrode and the drain electrode over the dielectric material layer prior to, or after, formation of the stack; and depositing a tunneling dielectric barrier liner on the stack or on the assembly. The tunneling dielectric barrier liner is in contact with the active layer, the source electrode, and the drain electrode after formation of the stack and the assembly.