Metal Oxide CMOS TFT Channels via Hydrogen-Modulated Conductivity
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Solution Overview
Problem
The manufacturing of complementary thin film transistors (TFTs) is costly due to the need for separate deposition processes for p-channel and n-channel transistors, which increases processing steps and time.
Innovation Solution
A single semiconductor channel material deposition process is used to form both n-type and p-type metal oxide semiconductor channels by modulating oxygen vacancy concentration, eliminating the need for separate channel material deposition processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate deposition processes are used for p-channel and n-channel transistors, then the conductivity type of channel material can be precisely controlled, but the manufacturing cost and processing time increase significantly
Solution Approach 1:
The patent merges the separate deposition processes for p-channel and n-channel transistors into a single deposition process. By using one deposition step to form the semiconductor layer and then applying selective hydrogenation treatment to different regions, the patent eliminates the need for multiple deposition processes while maintaining precise conductivity control through post-deposition modification.
Solution Approach 2:
The patent changes the physical or chemical parameters of the semiconductor layer after deposition by controlling hydrogen concentration in different regions. By varying the hydrogenation conditions (such as hydrogen plasma treatment or hydrogen annealing parameters) in specific device regions, the patent transforms the conductivity type from p-type to n-type without requiring separate deposition processes.
2Reliability
If multiple processing steps are used to deposit and pattern two types of compound semiconductor materials, then the device characteristics can be optimized, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts the conductivity type differentiation step from the deposition process itself and places it in the post-deposition treatment stage. By depositing a single semiconductor layer and then applying selective hydrogenation, the patent separates the material formation step from the conductivity control step, reducing processing complexity while maintaining device characteristic optimization.
Solution Approach 2:
The patent performs the semiconductor layer deposition in advance as a common step for both p-channel and n-channel transistors, then applies selective hydrogenation treatment to achieve the desired conductivity types. This preliminary deposition action reduces the number of subsequent processing steps and simplifies the overall manufacturing flow.
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
This approach reduces manufacturing costs and time while ensuring consistent process control and reliability of device characteristics for complementary field-effect transistors.
Implementation Method 1
electrical conductivity of a metal oxide semiconductor material may be modulated through control of local density of oxygen vacancies
Implementation Method 2
an amorphous metal oxide layer may be deposited over a sequence of surfaces
Data Source
AI summary
A combination of a first-type insulating surface and a second-type insulating surface may be formed over a substrate. The first-type insulating surface is a surface of a hydrogen-containing dielectric material, and the second-type insulating surface of a hydrogen-impermeable surface. An amorphous metal oxide layer may be deposited on the first-type insulating surface and the second-type insulating surface. An anneal process may be performed at an elevated temperature. A first portion of the amorphous metal oxide layer in contact with the first-type insulating surface is converted into a p-type metal oxide semiconductor layer, and a second portion of the amorphous metal oxide layer in contact with the second-type insulating surface is converted into an n-type metal oxide semiconductor layer. Complementary thin-film transistors may be formed using the semiconductor structure.