Nitride Semiconductor Source Region Deposition After Dehydrogenation
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Solution Overview
Problem
The existing ion implantation technique for forming n-type source regions in nitride semiconductor devices results in low activation rates due to defects and mixing of p-type impurities, such as magnesium, which affects the performance of the semiconductor device.
Innovation Solution
A nitride semiconductor device with a source region made of a deposited film, where the source region is formed after releasing hydrogen from the body region through dehydrogenation annealing, avoiding the defects and impurity mixing associated with ion implantation, and using deposition techniques like CVD or PVD for source region formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ion implantation technique is used to form n-type source region, then the source region can be formed, but the activation rate is low due to defects and mixing of p-type impurities
Solution Approach 1:
The patent replaces the mechanical ion implantation process with a chemical deposition process. Instead of physically implanting ions that create defects and mixing, the invention uses chemical vapor deposition or molecular beam epitaxy to grow the source region as a deposited film, eliminating the harmful mechanical effects of ion implantation while achieving high activation rates
Solution Approach 2:
The patent changes the fundamental formation parameter of the source region from ion implantation (physical process) to deposition (chemical process). This parameter change transforms the source region formation mechanism, allowing for higher activation rates and lower defect densities by controlling deposition conditions rather than implantation conditions
2Reliability
If ion implantation is used to form source region, then n-type doping can be achieved, but p-type impurities mix into the source region reducing performance
Solution Approach 1:
The patent substitutes the mechanical ion implantation method with a chemical deposition method. The deposition process grows the source region material layer-by-layer from vapor or molecular beams, preventing mixing with underlying p-type impurities that occurs during ion implantation, thereby improving device reliability
Solution Approach 2:
The patent introduces a deposition process as an intermediary method between the ion source and the substrate. Instead of directly implanting ions that cause mixing, the deposition process acts as an intermediate step that deposits material in a controlled manner, preventing direct contact and mixing between the source region material and p-type impurities
3Ease of manufacture
If high-work-function metal electrodes are used, then electrical connection can be achieved, but on-resistance increases
Solution Approach 1:
The patent changes the material parameter of the electrode from high-work-function metal to low-work-function material. This parameter change directly reduces the Schottky barrier height at the electrode-semiconductor interface, lowering on-resistance and energy loss while maintaining ease of manufacture through standard deposition techniques
Solution Approach 2:
The patent employs composite material structures for the electrode, combining low-work-function materials with appropriate thicknesses and configurations. This composite approach optimizes both the electrical connection ease and the reduction of on-resistance, achieving low contact resistance while maintaining manufacturability
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 enhances the activation rate of the source region and body region, reducing defect density and eliminating the need for high-work-function metal electrodes, resulting in lower on-resistance and improved threshold stability in nitride semiconductor devices.
Implementation Method 1
releasing hydrogen from the body region by performing a dehydrogenation annealing treatment
Implementation Method 2
depositing a source region of the first conductivity type on the body region
Data Source
AI summary
A nitride semiconductor device includes a drift region, a body region, a source region, an insulated gate, and a source electrode. The drift region has a first conductivity type and is made of a nitride semiconductor. The body region has a second conductivity type, is made of a nitride semiconductor, and is disposed on the drift region. The source region has the first conductivity type and is separated from the drift region by the body region. The insulated gate faces a portion of the body region that is located between the drift region and the source region. The source electrode is electrically connected to the body region and the source region. The source region is made of a deposited film.