SOI Support Substrate Precipitation Control for Stable Resistivity
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Solution Overview
Problem
The challenge lies in manufacturing semiconductor-on-insulator (SOI) structures that maintain high electrical resistivity and resistance to slip lines, while minimizing mechanical stresses and ensuring stable electrical resistivity, especially for applications in high-frequency ranges with gate lengths less than 65 nm.
Innovation Solution
A process involving the assembly of a support substrate with interstitial nitrogen and oxygen, followed by a nucleation stage to form seeds of oxygen and nitrogen precipitates, and a stabilization stage to grow these precipitates to a controlled size, thereby achieving the desired electrical resistivity and resistance to slip lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the concentration of interstitial oxygen in the support substrate is increased to prevent slip lines, then the resistance to slip lines is improved, but the electrical resistivity becomes unstable and decreases
Solution Approach 1:
The patent changes the chemical composition parameter by introducing interstitial nitrogen (10^14 to 10^15 atoms/cm³) alongside controlled interstitial oxygen (15-25 old ppma). This parameter change allows the system to achieve slip line resistance through nitrogen precipitation while maintaining electrical resistivity stability, as nitrogen precipitates block dislocations without forming thermal donors that would degrade resistivity.
Solution Approach 2:
The support substrate is designed as a composite structure containing both interstitial oxygen and interstitial nitrogen in specific concentrations. This composite approach combines the slip line blocking capability of oxygen precipitates with the electrical resistivity stability provided by nitrogen, creating a synergistic effect where each element compensates for the other's drawbacks.
2Reliability
If the concentration of interstitial oxygen is increased to block dislocation propagation, then slip line formation is prevented, but thermal donors are generated causing electrical resistivity to fall
Solution Approach 1:
Interstitial nitrogen acts as an intermediary element that enables slip line prevention without the harmful side effects of high oxygen concentrations. The nitrogen forms precipitates that block dislocation propagation similarly to oxygen precipitates, but without generating thermal donors. This intermediary substance allows the system to achieve the beneficial effect of dislocation blocking while avoiding the harmful effect of resistivity degradation.
3Stability of the object's composition
If weakly enriched substrates with low interstitial oxygen are used to control resistivity, then electrical resistivity stability is improved, but slip line resistance becomes insufficient for small-sized components
Solution Approach 1:
The patent modifies the compositional parameters by introducing interstitial nitrogen (10^14 to 10^15 atoms/cm³) while maintaining low interstitial oxygen (15-25 old ppma). This parameter combination allows the substrate to achieve adequate slip line resistance through nitrogen precipitate formation, which compensates for the reduced oxygen content, while preserving electrical resistivity stability that would be lost with higher oxygen concentrations.
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 process effectively maintains high and stable electrical resistivity while minimizing slip lines and mechanical stresses, even in small-sized components, thus addressing the challenges of high-frequency applications.
Implementation Method 1
increasing the initial concentration of interstitial oxygen of the support substrate and, by the application of heat treatments, causing the interstitial oxygen to precipitate in the form of oxygen precipitates or defects known under the acronym BMD (Bulk Micro Defects). The oxygen precipitates are then sufficiently big and numerous to, in the same way as the interstitial oxygen, block the propagation of the dislocations
Implementation Method 2
by the application of heat treatments, causing the interstitial oxygen to precipitate in the form of oxygen precipitates or defects known under the acronym BMD (Bulk Micro Defects)
Data Source
AI summary
A method for producing a semiconductor-on-insulator structure comprises the steps of: —joining a support substrate with a donor substrate, the support substrate having an electrical resistivity greater than or equal to 500 Ω·cm and containing interstitial nitrogen and interstitial oxygen, the initial concentration of interstitial oxygen in the support substrate being between 15 and 25 old ppma, the donor substrate including a semiconductor layer, an electrically insulating layer being at the interface between the support substrate and the donor substrate; and—transferring the semiconductor layer onto the support substrate, the method further comprising a nucleation step comprising a heat treatment in order to precipitate part of the oxygen and nitrogen so as to form nuclei of oxygen and nitrogen precipitates, and a stabilization step comprising a heat treatment in order to grow the nuclei to a size of between 10 and 50 nm.