GaN JBS P-Type Region Formation by Mg Diffusion Annealing
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Solution Overview
Problem
The existing ion implantation method for creating a P-type region in Junction Barrier Schottky diodes (JBS) results in high lattice damage, inaccurate channel width, and unreliable PN junctions, leading to leakage current issues.
Innovation Solution
A semiconductor manufacturing method involving sequential stacking of layers, etching to form openings, and forming a P-type region through high-temperature annealing to diffuse metal ions, specifically Mg ions, into the GaN drift layer, avoiding lattice damage and improving region quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ion implantation is used to create a P-type region, then the P-type region can be formed, but high lattice damage occurs and the channel width becomes inaccurate
Solution Approach 1:
The patent replaces the mechanical ion implantation process with a chemical diffusion process. Instead of physically implanting ions at high energy (mechanical approach), the invention uses thermal diffusion where magnesium atoms diffuse into the GaN layer through a magnesium oxide layer at high temperature (chemical-thermal approach). This substitution eliminates lattice damage while achieving the desired P-type region formation and accurate channel width control.
Solution Approach 2:
The patent changes the fundamental parameters of the doping process: instead of using high-energy ion implantation, it employs high-temperature thermal diffusion (parameters: temperature ~900-1100°C, time: controlled duration). This parameter change transforms the process from a mechanical impact-based method to a thermal diffusion-based method, resolving the lattice damage issue while maintaining precise channel width control through the magnesium oxide layer thickness.
2Reliability
If high ion implantation energy is used, then P-type region formation is achieved, but the implantation apparatus requirements become very high and lattice damage increases
Solution Approach 1:
The patent replaces the complex high-energy ion implantation apparatus with a standard thermal diffusion processing system. The magnesium diffusion process uses conventional semiconductor fabrication equipment capable of high-temperature processing, eliminating the need for specialized high-energy ion implanters and significantly reducing device complexity while achieving reliable P-type region formation.
3Manufacturing precision
If ion implantation is used, then P-type region is created, but diffusion phenomenon results in inaccurate channel width and unreliable PN junctions
Solution Approach 1:
The patent introduces a magnesium oxide (MgO) layer as an intermediary between the magnesium source and the GaN layer. This MgO layer acts as a controlled diffusion barrier that allows precise control over magnesium atom diffusion depth and distribution. The intermediary layer ensures accurate channel width definition and reliable PN junction formation by controlling the diffusion process, preventing the unwanted diffusion phenomena associated with direct ion implantation.
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 method enhances the quality of the P-type region by increasing Mg atom activation efficiency and reducing lattice damage, resulting in improved on-state and off-state characteristics of JBS diodes.
Implementation Method 1
forming a P-type region by performing high-temperature annealing to diffuse metal ions from the metal layer into the GaN drift layer under the opening
Implementation Method 2
forming a P-type region by performing high-temperature annealing to diffuse metal ions
Data Source
AI summary
Disclosed are a semiconductor structure and a manufacturing method thereof. The manufacturing method includes: sequentially stacking a substrate, a GaN drift layer and a protective layer; etching the protective layer to form an opening penetrating through the protective layer; forming a metal layer at least located in the opening; and forming a P-type region by performing high-temperature annealing to diffuse metal ions from the metal layer into the GaN drift layer under the opening. According to the present disclosure, the P-type region is formed by the Mg diffusion. The diffused Mg may better replace the Ga vacancy, in the GaN, so that most of the incorporated Mg atoms are located at the Ga vacancy, and thus the proportion of Mg atoms in the Ga vacancy is increased, the probability of binding with an H-bond is reduced, and the activation efficiency of the Mg is increased.