Oxygen Barrier Layer for SeOI Vacancy Cluster Reduction
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Solution Overview
Problem
The production of semiconductor-on-insulator (SeOI) structures with thin layers faces challenges due to defects from vacancy clusters (COPs), which are difficult to eliminate effectively using existing methods like thermal annealing, especially when the clusters are large compared to the layer thickness, leading to operational failures and increased production costs.
Innovation Solution
The introduction of an oxygen barrier layer during the transfer process limits oxygen diffusion and enhances the effectiveness of vacancy cluster dissolution by providing a barrier to oxygen migration, allowing for the use of substrates with higher COP densities without increasing their size, thereby improving defect characteristics and processing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal annealing is used to dissolve vacancy clusters, then defect density is reduced, but oxygen diffusion increases causing harmful effects
Solution Approach 1:
An oxygen barrier layer is introduced as an intermediary between the thin semiconductor layer and the oxygen source. This barrier layer prevents oxygen diffusion to the thin layer during thermal annealing, allowing the annealing process to dissolve vacancy clusters without the harmful side effect of oxygen contamination.
Solution Approach 2:
The structure is segmented into distinct layers with different functions: the thin semiconductor layer containing vacancy clusters to be dissolved, the oxygen barrier layer to prevent oxygen diffusion, and the oxygen source region. This segmentation allows independent optimization of each layer's properties and functions.
2Ease of manufacture
If substrates with high COP density are used, then production cost decreases, but defect size increases leading to through defects
Solution Approach 1:
The patent changes the critical parameter from substrate COP density to thin layer thickness. By making the thin layer sufficiently thin, even substrates with higher COP densities can produce acceptable final products because the vacancy clusters cannot grow large enough to create through defects when constrained by the thin layer geometry.
Solution Approach 2:
The thin layer is transferred to the support substrate before the thermal annealing process. This preliminary positioning constrains the vacancy clusters within the thin layer boundaries, preventing them from growing into through defects during subsequent annealing, even when starting from substrates with higher initial COP densities.
3Reliability
If previous heat treatment is applied to reduce COPs, then vacancy cluster density decreases, but bonding quality deteriorates
Solution Approach 1:
The transfer process itself is performed as a preliminary action before thermal annealing. By transferring the thin layer first and then applying heat treatment, the bonding interface is already established and protected, allowing subsequent annealing to reduce vacancy clusters without compromising bonding quality.
Solution Approach 2:
The support substrate acts as an intermediary that receives the thin layer in a constrained state. This intermediary structure allows subsequent thermal processing to occur without directly affecting the bonding interface, thereby maintaining bonding quality while still enabling vacancy cluster reduction.
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 effectively reduces the density of vacancy clusters in transferred thin layers, enhancing the quality and efficiency of SeOI structures while maintaining cost-effectiveness and avoiding bonding or recycling issues associated with previous heat treatments.
Implementation Method 1
an oxygen barrier layer to be in contact with the transferred thin layer is provided as part of the insulating layer, the oxygen barrier layer limiting diffusion of oxygen toward the thin layer during the curing
Implementation Method 2
the transferred thin layer is cured to reduce the first density of vacancy clusters to a second density
Data Source
AI summary
Methods for forming semiconductor structures comprising a layer transferred from a donor substrate are provided in which the resulting structure has improved quality with respect to defects and resulting structures therefrom. For example, a semiconductor-on-insulator (SeOI) structure can be formed by a method comprising:—providing a donor substrate having a first density of vacancy clusters;—providing an insulating layer; —transferring a thin layer from the donor substrate to a support substrate with the insulating layer thereon;—curing the transferred thin layer to reduce the first density of vacancy clusters to a second density; and being characterized in that the step of providing an insulating layer comprises providing an oxygen barrier layer to be in contact with the transferred thin layer, the oxygen barrier layer limiting diffusion of oxygen toward the thin layer during the curing.