Semiconductor Passivation via Hydrazine Nitridation
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Solution Overview
Problem
Current passivation techniques for high charge-carrier mobility semiconductor materials, such as silicon germanium and group III-V semiconductors, face challenges including high cost, low throughput, and reliability issues due to undesirable inversion thickness, conformality problems, and high interface state densities, particularly in FinFET/vertical nanowire devices.
Innovation Solution
The method involves passivating high mobility semiconductor surfaces by removing native oxide and forming a semiconductor oxynitride layer through nitridation using hydrazine or its derivatives, which reacts with the surface to form a nitrogen-containing film, providing a stable and low oxide trap density layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional passivation techniques are used for high mobility semiconductor materials, then device performance may be maintained, but oxide trap density and interface state density increase, reducing device reliability
Solution Approach 1:
The patent changes the chemical composition parameters of the passivation layer by incorporating nitrogen into the oxide matrix, transforming it from a conventional oxide to an oxynitride material. This compositional parameter change reduces oxide trap density and interface state density, thereby improving device reliability without compromising performance
Solution Approach 2:
The patent creates a composite oxynitride material by combining oxide and nitride phases, where the nitrogen-containing groups are embedded within the oxide matrix. This composite structure provides beneficial properties from both oxide (stability, coverage) and nitride (low trap density, low interface states) materials, resolving the reliability issue
2Reliability
If passivation is performed to improve electrical properties, then device performance improves, but the process becomes more complex with multiple steps required
Solution Approach 1:
The patent merges the oxidation and nitridation steps into a single combined process where nitrogen is incorporated during oxide formation. This consolidation reduces the number of separate process steps while achieving the desired oxynitride passivation layer with low oxide trap density and improved electrical properties
Solution Approach 2:
The patent performs preliminary nitrogen incorporation during the oxide formation step, so that the passivation layer is formed with the correct composition from the beginning. This preliminary action eliminates the need for subsequent separate nitridation steps, reducing process complexity while ensuring proper passivation
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 results in exceptionally low oxide trap density and interface state density, enhancing device reliability and performance by forming a nitrogen-containing layer that is highly stable and suitable for both p-doped and n-doped germanium devices.
Implementation Method 1
thermally nitriding the semiconductor oxide-containing film by exposing the semiconductor oxide-containing film to at least one of hydrazine and a hydrazine derivative
Implementation Method 2
nitridation using a nitrogen precursor comprising at least one of hydrazine and a hydrazine derivative... which reacts with the surface to form a nitrogen-containing film
Implementation Method 3
passivating the surface of a substrate comprising a high mobility semiconductor by removing native semiconductor oxide from the surface
Data Source
AI summary
In some embodiments, a semiconductor surface having a high mobility semiconductor may be effectively passivated by nitridation, preferably using hydrazine, a hydrazine derivative, or a combination thereof. The surface may be the semiconductor surface of a transistor channel region. In some embodiments, a semiconductor surface oxide layer is formed at the semiconductor surface and the passivation is accomplished by forming a semiconductor oxynitride layer at the surface, with the nitridation contributing nitrogen to the surface oxide to form the oxynitride layer. The semiconductor oxide layer may be deposited by atomic layer deposition (ALD) and the nitridation may also be conducted as part of the ALD.