High Temperature Layer Transfer for Semiconductor Heterostructures
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Solution Overview
Problem
Current methods for transferring layers in semiconductor-on-insulator heterostructures, particularly those with thin or no oxide layers, suffer from defects such as surface roughness and voids due to the diffusion of species during the transfer process, which are not effectively addressed by existing techniques like SMART CUT or plasma treatments.
Innovation Solution
A method involving ionic implantation of species to form microcavities or platelets in the donor substrate, followed by a second implantation of silicon ions to neutralize precursors and increase the cleavage temperature, allowing for higher temperature splitting annealing to enhance bonding energy and reduce defects, specifically using temperatures above 575°C for silicon substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If low temperature annealing is used to reduce defects, then surface quality is improved, but bonding energy is insufficient leading to poor transfer
Solution Approach 1:
The patent changes the temperature parameter from low temperature (conventional) to high temperature (above 575°C) annealing. This parameter change simultaneously increases bonding energy for better transfer while the specific high-temperature process maintains surface quality by controlling defect formation through the engineered microcavity layer.
2Strength
If high temperature annealing is used to increase bonding energy, then transfer quality is improved, but surface defects increase due to species diffusion
Solution Approach 1:
The patent performs preliminary implantation of silicon ions to create a microcavity layer before the high-temperature annealing step. This preliminary action prepares the structure to withstand high temperatures by providing a controlled pathway for species diffusion, thereby maintaining surface quality while enabling the high bonding energy needed for quality transfer.
Solution Approach 2:
The microcavity layer formed by silicon ion implantation acts as an intermediary structure between the donor substrate and the external environment. It mediates the high-temperature annealing process by controlling species diffusion, allowing high bonding energy to be achieved without the harmful surface defects that would normally result from such temperatures.
3Strength
If plasma treatment is applied to increase bonding energy, then interface bonding is improved, but process complexity increases
Solution Approach 1:
The patent changes the approach from chemical plasma treatment to physical high-temperature thermal annealing. This parameter change achieves the same goal of increasing bonding energy through a different physical mechanism, simplifying the process by eliminating plasma chemistry steps while maintaining effective bonding.
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 significantly reduces defects in the heterostructure by increasing the bonding energy between the donor and receiving substrates, resulting in a higher quality transfer with fewer voids and improved surface quality.
Implementation Method 1
a) bombarding one face of a donor substrate (for example, formed from silicon) with light ions of the hydrogen or rare gas type (for example, hydrogen and/or helium) to implant those ions in sufficient concentration into the substrate; the implanted zone creates a layer of weakness by forming microcavities or platelets
Implementation Method 2
c) splitting annealing, whereby the effect of a crystalline rearrangement and pressure in the microcavities or platelets formed from the implanted species causes fracture or cleavage at the implanted layer
Implementation Method 3
the effect of a crystalline rearrangement and pressure in the microcavities or platelets formed from the implanted species causes fracture or cleavage
Implementation Method 4
b) bringing that face of the donor substrate into intimate contact (bonding) with a receiving substrate
Data Source
AI summary
A method of transferring a layer from a donor substrate onto a receiving substrate comprises ionic implantation of at least one species into the donor substrate and forming a layer of concentration of the species intended to form microcavities or platelets; bonding the donor substrate with the receiving substrate by wafer bonding; and splitting at high temperature to split the layer in contact with the receiving substrate by cleavage, at a predetermined cleavage temperature, at the layer of microcavities or platelets formed in the donor substrate. The method further comprises, after the first implantation step and before the splitting step, ionic implantation of silicon ions into the donor substrate to form a layer of concentration of silicon ions in the donor substrate, the layer of concentration of silicon ions at least partially overlapping the layer of concentration of the species intended to form microcavities or platelets.