Self-Aligned III-Nitride Doping With Capped High-Temperature Diffusion
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Solution Overview
Problem
Conventional methods face challenges in forming selective-area doped regions in III-nitride semiconductor materials due to high temperatures required for dopant activation, which can lead to material decomposition and lattice damage, making precise junction depth control difficult, especially for p-type doping.
Innovation Solution
The method involves forming a p-type dopant source layer on an n-type doped region, diffusing the p-type dopant into the semiconductor layer, and using a capping layer to prevent decomposition, followed by self-alignment techniques to define p-type and n-type regions without additional photolithographic steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high temperature annealing is used to activate dopants in III-nitride semiconductors, then dopant activation is improved, but material decomposition and lattice damage occur
Solution Approach 1:
A capping layer is introduced as an intermediary between the dopant source layer and the III-nitride semiconductor layer. This capping layer prevents direct decomposition of the semiconductor material during high-temperature annealing while allowing dopant diffusion to occur, thus resolving the contradiction between achieving dopant activation and preventing material degradation
Solution Approach 2:
The patent changes the physical and chemical parameters of the processing environment by introducing a capping layer that modifies the thermal and chemical conditions at the semiconductor surface during annealing, enabling high-temperature processing without material decomposition
2Manufacturing precision
If conventional photolithographic steps are used for selective-area doping, then doping precision is improved, but process complexity increases
Solution Approach 1:
The dopant source layer itself serves as the alignment reference for subsequent processing steps. By forming the dopant source layer with the desired pattern and using it as a mask and source simultaneously, the process eliminates the need for separate photolithographic alignment steps, achieving self-aligned doping that reduces process complexity while maintaining precision
Solution Approach 2:
The patent merges the dopant source layer formation with the doping process itself. The same layer that provides dopants also defines the doping pattern through its spatial distribution, combining what would traditionally be separate masking and doping operations into a single integrated process
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 enables precise, self-aligned formation of p-type and n-type doped regions in III-nitride semiconductors, reducing misalignment and material degradation, facilitating the creation of high-performance semiconductor devices.
Implementation Method 1
The p-type dopant is diffused from the p-type dopant source layer through the n-type doped region into the semiconductor layer
Implementation Method 2
a capping layer/layers may be used to reduce/prevent decomposition of III-nitride semiconductor materials during high temperature annealing operations
Data Source
AI summary
According to some embodiments of the present disclosure, methods of forming a semiconductor device on a semiconductor layer having opposing first and second surfaces are disclosed. An n-type doped region including an n-type dopant may be formed at the first surface of the semiconductor layer. A p-type dopant source layer including a p-type dopant may be formed on the n-type doped region. The p-type dopant may be diffused from the p-type dopant source layer through the n-type doped region into the semiconductor layer to form a p-type doped region of the semiconductor layer, and the p-type doped region of the semiconductor layer may be between the n-type doped region and the second surface of the semiconductor layer. After diffusing the p-type dopant, the p-type dopant source layer may be removed.