Metal Oxide Gate Layers for Threshold Voltage Tuning
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Solution Overview
Problem
Conventional semiconductor device scaling techniques face challenges in finding suitable conducting materials for gate electrodes, particularly for threshold voltage shift and dipole shifting layers in aggressively scaled CMOS devices.
Innovation Solution
A method for depositing metal oxide layers on a substrate involves providing a substrate in a reaction chamber and flowing precursors comprising zinc, gallium, or aluminum with specific ligands to deposit oxide layers, repeating the process to achieve desired thicknesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional scaling techniques are used to reduce device dimensions, then device density and speed improve, but suitable conducting materials for gate electrodes become difficult to find
Solution Approach 1:
The patent changes the material composition parameters by introducing metal oxide layers (ZnO, Ga2O3, Al2O3) with specific stoichiometries and doping concentrations. This resolves the contradiction by providing suitable conducting materials for scaled devices through compositional optimization rather than relying on conventional materials that fail at aggressive scaling nodes
Solution Approach 2:
The patent employs composite material structures including doped metal oxide layers (e.g., aluminum-doped zinc oxide, indium-gallium-zinc-oxide) and multi-layer gate electrode configurations. These composite materials provide the necessary electrical properties for scaled devices while maintaining material suitability that conventional single-material approaches cannot achieve
2Ease of manufacture
If conventional materials are used for gate electrodes in aggressively scaled CMOS devices, then manufacturing process remains simple, but threshold voltage shift and dipole shifting problems occur
Solution Approach 1:
The patent modifies material parameters by controlling oxidation states, doping levels, and layer thicknesses of metal oxide materials. These parameter changes enable threshold voltage tuning and dipole shifting control while maintaining compatibility with existing manufacturing processes, thus resolving the contradiction between manufacturing simplicity and device reliability
Solution Approach 2:
The patent introduces metal oxide layers as intermediary materials between the gate electrode and channel. These intermediary layers (such as ZnO, Ga2O3, Al2O3) provide dipole shifting functionality and threshold voltage control, mediating the interaction between gate electrode and channel to prevent direct harmful effects while maintaining process simplicity
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 method enables the formation of zinc or gallium oxide layers and aluminum oxide layers, providing improved materials for gate electrodes that can effectively tune threshold voltage and mitigate damage during deposition.
Implementation Method 1
flowing a first precursor comprising zinc or gallium or a combination thereof and an oxygen species into the chamber to deposit a first oxide layer on a top surface of the substrate
Implementation Method 2
flowing a second precursor into the chamber to deposit a second oxide layer on the first oxide layer wherein the second precursor comprises aluminum having at least one R ligand and at least one L ligand
Data Source
AI summary
Method, system and apparatus for forming one or more metal oxide layers on a substrate is disclosed. An example method comprises a) providing a substrate in a reaction chamber, b) flowing a first precursor comprising zinc or gallium or a combination thereof and an oxygen species into the chamber to deposit a first oxide layer on a top surface of the substrate, c) flowing a second precursor into the chamber to deposit a second oxide layer on the first oxide layer wherein the second precursor comprises aluminum having at least one R ligand and at least one L ligand, wherein the R ligand is an alkyl ligand and wherein the R ligand and the L ligand are different and repeating steps b) or c) or a combination thereof until a desired thickness of the first oxide layer or the second oxide layer, or a combination thereof is achieved.