Nitride Semiconductor Doping Profile for Deep Junctions
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Solution Overview
Problem
Conventional nitride semiconductor devices face challenges in forming N-type regions with deep doping, requiring ultra-high energy ion implantation, leading to high fabrication costs and issues with doping tails, especially when forming shallow source contact regions with low atomic weight elements.
Innovation Solution
The nitride semiconductor device incorporates a junction region with a doping concentration of oxygen or silicon, extending from the surface to a deeper nitride semiconductor layer, and a source region with a higher doping concentration using elements like silicon or germanium, ion-implanted at shallower depths, allowing for reduced damage and eliminating the need for ultra-high energy implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If ultra-high energy ion implantation (1 MeV or more) is used to form deep N-type regions, then doping depth is improved, but fabrication cost increases due to expensive facilities
Solution Approach 1:
The patent changes the energy parameter of ion implantation from ultra-high energy (1 MeV or more) to lower energy levels, combined with multiple implantation steps to achieve the desired doping depth without requiring expensive ultra-high energy facilities
Solution Approach 2:
The patent divides the doping process into multiple sequential ion implantation steps with different energies and doses, rather than using a single ultra-high energy implantation, thereby achieving deep doping through cumulative effect while using standard equipment
2Quantity of substance
If shallow source contact region is formed with high doping concentration using low atomic weight elements, then doping concentration is improved, but doping tail extends deeply due to low atomic weight
Solution Approach 1:
The patent applies different dopant materials with different atomic weights to different regions: using higher atomic weight elements (Si, Ge) for the shallow source contact region to minimize tail extension, while using appropriate dopants for the deeper junction region to achieve the desired electrical characteristics
3Reliability
If high doping concentration is achieved in shallow region, then electrical conductivity is improved, but control over doping profile becomes difficult
Solution Approach 1:
The patent segments the doping process into multiple steps with different energies, doses, and timing, allowing precise control over the doping profile shape and concentration distribution, achieving high conductivity in the source region while maintaining proper junction characteristics
Solution Approach 2:
The patent performs preliminary ion implantation steps to establish the doping profile foundation before final high-concentration doping, enabling better control over the overall doping profile and preventing excessive tail extension
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 reduces fabrication costs and improves the controllability of doping concentrations, minimizing doping tails and enhancing the electrical characteristics of the nitride semiconductor device.
Implementation Method 1
forming an N-type region by ion-implanting N-type dopants
Data Source
AI summary
A nitride semiconductor device is provided, comprising: a first nitride semiconductor layer of a first conductivity-type; a second nitride semiconductor layer of a second conductivity-type provided above the first nitride semiconductor layer; a junction region of a first conductivity-type which is provided to extend in a direction from a front surface of the second nitride semiconductor layer to the first nitride semiconductor layer and has a doping concentration NJFET equal to or higher than that of the first nitride semiconductor layer; and a source region of a first conductivity-type which is provided more shallowly than the junction region and has a doping concentration equal to or higher than the doping concentration NJFET, wherein a dopant of the source region is an element with an atomic weight larger than that of a dopant in the junction region.