Hafnium Titanium Oxide Gate Stack for Leakage Reduction
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Solution Overview
Problem
Current methods for forming gate insulation layers in semiconductor devices using hafnium oxide result in increased leakage current due to impurity penetration and low dielectric constant issues, particularly when the design rule is below 50 nm, limiting the effectiveness of hafnium silicon oxide layers.
Innovation Solution
The method involves forming a thin film of hafnium titanium oxide using an atomic layer deposition process by alternately introducing hafnium and titanium precursors with oxidants, allowing for the formation of a high dielectric constant layer that reduces leakage current and enhances electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a hafnium oxide layer is used as the gate insulation layer, then the equivalent oxide thickness can be reduced, but the leakage current increases due to impurity penetration and low dielectric constant
Solution Approach 1:
The patent applies composite materials by forming a multi-layer structure consisting of a first high-k dielectric layer (hafnium oxide) and a second high-k dielectric layer (hafnium silicon oxide) with different dielectric constants. This composite structure combines the advantages of both materials: the first layer provides thin EOT while the second layer provides high dielectric constant to reduce leakage current, thereby resolving the contradiction between achieving thin EOT and maintaining low leakage current.
2Reliability
If a hafnium silicon oxide layer is used to reduce leakage current, then the dielectric constant improves, but the layer is not suitable for design rules below 50 nm due to low dielectric constant
Solution Approach 1:
The patent uses composite materials by stacking two different high-k dielectric layers with complementary properties. The first layer (hafnium oxide) has higher dielectric constant suitable for small design rules, while the second layer (hafnium silicon oxide) provides additional leakage current reduction. This composite approach allows the structure to meet both requirements: suitability for sub-50nm design rules and effective leakage current reduction.
3Ease of manufacture
If doped polysilicon gate electrode is formed on hafnium oxide layer, then the gate structure can be formed, but electron mobility decreases due to impurity penetration
Solution Approach 1:
The patent introduces the first high-k dielectric layer (hafnium oxide) as an intermediary barrier between the doped polysilicon gate electrode and the channel region. This intermediary layer prevents impurity penetration from the gate electrode to the channel, thereby maintaining electron mobility while still allowing the gate structure to be formed. The intermediary layer resolves the contradiction by providing both structural functionality and protective function.
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 resulting hafnium titanium oxide layer provides improved electrical characteristics, such as reduced leakage current and increased dielectric constant, making it suitable for semiconductor devices with smaller design rules.
Implementation Method 1
chemisorbing a first portion of the first reactant to the substrate
Implementation Method 2
physisorbing a second portion of the first reactant to the substrate and the chemisorbed first portion of the first reactant
Implementation Method 3
forming a first thin film including hafnium oxide on the substrate by chemically reacting the first oxidant with the chemisorbed first portion of the first reactant
Implementation Method 4
chemisorbing a first portion of the second reactant to the first thin film
Implementation Method 5
physisorbing a second portion of the second reactant to the first thin film and the chemisorbed first portion of the second reactant
Implementation Method 6
forming a second thin film including titanium oxide on the first thin film, by chemically reacting the second oxidant with the chemisorbed first portion of the second reactant
Data Source
AI summary
The present invention can provide methods of manufacturing a thin film including hafnium titanium oxide. The methods can include introducing a first reactant including a hafnium precursor onto a substrate; chemisorbing a first portion of the first reactant to the substrate, and physisorbing a second portion of the first reactant to the substrate and the chemisorbed first portion of the first reactant; providing a first oxidant onto the substrate; forming a first thin film including hafnium oxide on the substrate; introducing a second reactant including a titanium precursor onto the first thin film; chemisorbing a first portion of the second reactant to the first thin film, and physisorbing a second portion of the second reactant to the first thin film and the chemisorbed first portion of the second reactant; providing a second oxidant onto the first thin film; and forming a second thin film including titanium oxide on the first thin film. The present invention can further provide methods of manufacturing a gate structure and a capacitor.