Titanium Oxide Gate Layer via PVD and Ozone Oxidation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The formation of titanium oxide layers in semiconductor devices, such as thin-film transistors (TFTs) and ferroelectric field effect transistors (FeFETs), is complex and time-consuming using atomic layer deposition (ALD), and controlling the titanium-to-oxygen (Ti—O) ratio is difficult, affecting transistor performance.
Innovation Solution
A physical vapor deposition (PVD) method is used to form a titanium layer, followed by ozone or ozone plasma exposure to oxidize it, allowing for a single cycle process that controls the Ti—O ratio by adjusting exposure time and deposition parameters, reducing complexity and time compared to ALD.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If atomic layer deposition (ALD) is used to form titanium oxide layers, then the layers can be formed with controlled thickness, but the process becomes complex and time-consuming
Solution Approach 1:
The patent extracts the oxidation step from the multi-step ALD process by using pre-formed titanium oxide layers deposited by sputtering, eliminating the need for repeated ALD cycles of titanium deposition followed by oxidation. This reduces process complexity while maintaining thickness control through direct deposition parameters.
Solution Approach 2:
The patent replaces the complex, time-consuming ALD process with a simpler sputtering process that uses readily available titanium oxide target materials. This substitution reduces both process complexity and fabrication time while achieving the required layer thicknesses for device operation.
2Manufacturing precision
If atomic layer deposition (ALD) is used to form titanium oxide layers, then the layers can be formed with controlled thickness, but the process takes a long time
Solution Approach 1:
The patent removes the time-consuming iterative cycles of ALD (deposition-oxidation-purge) by extracting the oxidation function and using physical vapor deposition of titanium oxide directly. This achieves thickness control through single-step deposition parameters rather than repeated cycles, dramatically increasing deposition rate.
Solution Approach 2:
The patent replaces the chemical deposition mechanism of ALD with physical vapor deposition (sputtering). This substitution enables faster material deposition rates while maintaining precise thickness control through adjustment of sputtering power, gas pressure, and deposition time, thereby improving productivity.
3Manufacturing precision
If atomic layer deposition (ALD) is used to form titanium oxide layers, then the layers can be formed, but controlling the titanium-to-oxygen (Ti—O) ratio is difficult
Solution Approach 1:
The patent extracts the Ti—O ratio control from the complex ALD process parameters (precursor flow rates, temperature, pulse timing) and simplifies it to direct control through sputtering power and deposition conditions. This reduces process complexity while maintaining precise compositional control.
Solution Approach 2:
The patent changes the control parameters from chemical deposition variables in ALD to physical deposition variables in sputtering. By adjusting sputtering power, gas pressure, and deposition time, the Ti—O ratio is precisely controlled through well-established relationships between these parameters and film composition, reducing process complexity.
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 enhances transistor performance by increasing memory window, ferroelectric polarization, and on-current while providing precise control over Ti—O ratio, leading to improved device endurance and efficiency.
Implementation Method 1
depositing a metal layer on the first layer by physical vapor deposition
Implementation Method 2
exposing the metal layer to ozone or ozone plasma
Implementation Method 3
exposing the metal layer to ozone or ozone plasma
Data Source
AI summary
A method of fabricating a device includes forming a first layer. The first layer may be a ferroelectric layer if the device is a ferroelectric field effect transistor (FeFET), or a gate dielectric layer if the device is a transistor. Alternatively, the first layer may be a channel of the device. A metal oxide layer is formed on the first layer by depositing a metal layer on the first layer by physical vapor deposition followed by exposing the metal layer to ozone or ozone plasma. A second layer is formed on the metal oxide layer. The forming of the metal oxide layer may further include, prior to the depositing of the metal layer, exposing the first layer to ozone or ozone plasma. The metal layer may be a titanium layer.