SOI Substrate Getter Layer for Low Leakage and Higher Breakdown
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Solution Overview
Problem
Mobile metal contaminants such as sodium and potassium in semiconductor-on-insulator (SOI) substrates induce higher leakage current and reduce breakdown voltage, which are not effectively addressed by existing technologies.
Innovation Solution
Incorporating a getter material with a halogen concentration profile, such as fluorine or chlorine, in the insulator layer to bind and neutralize these contaminants, thereby reducing leakage current and increasing breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mobile metal contaminants such as sodium and potassium are present in the insulator layer, then the insulator layer can be formed with standard materials and processes, but leakage current increases and breakdown voltage decreases
Solution Approach 1:
A getter layer is introduced as an intermediary between the handle substrate and the insulator layer. This getter layer selectively binds mobile metal contaminants (sodium, potassium) that would otherwise migrate into the insulator layer and cause harmful effects. The getter layer acts as a mediator that captures contaminants before they reach the insulator, thereby reducing leakage current and preventing breakdown voltage degradation without requiring changes to the insulator layer materials or formation processes.
Solution Approach 2:
The getter layer is formed in advance before the insulator layer is deposited. This preliminary action ensures that the getter material is already in position to capture mobile metal contaminants before they can migrate into the insulator layer during subsequent processing steps. By performing the contaminant capture function beforehand, the insulator layer can be formed with standard materials and processes while still achieving low leakage current and high breakdown voltage.
2Reliability
If a getter layer is added to bind mobile metal contaminants, then leakage current is reduced and breakdown voltage increases, but the device structure becomes more complex
Solution Approach 1:
The getter layer is positioned locally between the handle substrate and the insulator layer, specifically where mobile metal contaminants originate and migrate from. This localized placement ensures that the getter material is present exactly where it is needed to capture contaminants, while the rest of the insulator layer structure remains simple and can be formed with standard processes. The local quality approach allows contaminant binding functionality without requiring complex modifications throughout the entire device structure.
3Reliability
If the insulator layer is made thicker to reduce leakage current, then breakdown voltage increases, but parasitic capacitance and device area increase
Solution Approach 1:
The getter layer serves as an intermediary that actively removes mobile metal contaminants before they can reach the insulator layer. This mediator approach allows the use of thinner insulator layers because the contaminant source is eliminated at the getter layer interface. Without the getter layer, a thicker insulator would be needed to achieve the same low leakage current, but the getter layer enables thin insulator design while maintaining reliability, thereby reducing parasitic capacitance and device area.
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 getter material effectively binds mobile metal contaminants, leading to reduced leakage current and enhanced breakdown voltage in the insulator layer, thus improving the performance and reliability of SOI substrates.
Implementation Method 1
the oxide layer is subjected to a gettering process in which a halogen species is provided in the oxide layer to getter away the metal contaminants
Data Source
AI summary
Various embodiments of the present application are directed towards a semiconductor-on-insulator (SOI) substrate. The SOI substrate includes a handle substrate; a device layer overlying the handle substrate; and an insulator layer separating the handle substrate from the device layer. The insulator layer meets the device layer at a first interface and meets the handle substrate at a second interface. The insulator layer comprises a getter material having a getter concentration profile. The handle substrate contains getter material and has a handle getter concentration profile. The handle getter concentration profile has a peak at the second interface and a gradual decline beneath the second interface until reaching a handle getter concentration.