Trench Gate Etching Transition Layer for Precise GaN Barrier Depth
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing manufacturing processes for semiconductor devices using trench-gate technology face challenges in accurately controlling the etching depth, leading to poor controllability, uniformity, and stability of the threshold voltage, as well as surface damage and reliability issues due to etching damage, which complicates the production of high-electron-mobility transistors (HEMTs) based on AlGaN/GaN heterojunctions.
Innovation Solution
A method involving the growth of an etching transition layer in the semiconductor material layer, followed by dry etching until reaching the transition layer, and subsequent thermal treatment to completely remove the transition layer, thereby forming a trench structure with precise control and avoiding surface damage, ensuring high-quality interfaces and stable electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional trench gate etching is used to thin the barrier layer, then the two-dimensional electron gas in the gate region is exhausted to achieve enhanced mode control, but the etching depth control is difficult and process repeatability is poor
Solution Approach 1:
The patent introduces an etching transition layer as an intermediary between the upper and lower barrier layers. This transition layer has intermediate etching resistance, allowing the etching process to be precisely controlled and terminated when reaching this layer. The transition layer acts as a mediator that enables accurate depth control without directly etching into the lower barrier layer, thus improving both etching depth control and process repeatability.
Solution Approach 2:
The etching transition layer is grown in advance during the epitaxial growth process, before the etching step. This preliminary action of creating a distinct transition layer with different etching properties allows the subsequent etching process to self-terminate at a precise depth, eliminating the need for complex real-time depth monitoring and improving process repeatability.
2Manufacturing precision
If aggressive etching is used to achieve precise depth control, then the trench gate etching depth can be controlled, but etching damage such as nitrogen vacancy and dangling bond is caused on the barrier layer surface
Solution Approach 1:
The etching transition layer serves as a protective intermediary that absorbs the etching damage. By designing the transition layer with appropriate thickness and composition, the etching process can reach the desired depth while the transition layer itself bears the brunt of the etching damage, protecting the lower barrier layer and channel from direct etching damage such as nitrogen vacancies and dangling bonds.
Solution Approach 2:
The patent converts the potentially harmful etching damage into a beneficial feature by intentionally designing the transition layer to be the sacrificial element. The etching damage that would normally harm the device performance is instead confined to the transition layer, which is either removed or passivated in subsequent processing steps, thus transforming a harmful effect into a controlled and beneficial process feature.
3Manufacturing precision
If digital oxidation/wet etching technology is used to achieve high-precise etching, then the barrier layer can be precisely etched by oxidizing and corroding, but the etching depth of each cycle is almost single atomic layer requiring many cycles, thus low in efficiency
Solution Approach 1:
The patent segments the barrier layer structure into three distinct parts: upper barrier layer, etching transition layer, and lower barrier layer. This segmentation allows the etching process to be divided into two stages: a first stage that removes the upper barrier layer and transitions into the transition layer, and a second stage that completes the etching through the transition layer. This segmentation enables the use of more efficient etching methods while maintaining precision, avoiding the need for many single-atomic-layer etching cycles.
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 allows for precise control of trench depth, avoids etching damage, and enhances the repeatability and uniformity of the manufacturing process, ensuring stable electrical characteristics and compatibility for mass production of HEMTs and other semiconductor devices.
Implementation Method 1
subjecting the part of the etching transition layer located in the selected region to thermal decomposition through thermal treatment to be completely removed
Data Source
AI summary
The present application discloses a semiconductor device and a manufacturing method thereof. The manufacturing method comprises manufacturing a semiconductor material layer comprising two laminated semiconductor layers between which an etching transition layer is provided; and etching a part of one of semiconductor layers located in a selected region until etching is stopped after reaching or entering the etching transition layer, subjecting the part of the etching transition layer located in the selected region to thermal decomposition through thermal treatment to be completely removed, and realizing termination of thermal decomposition on another semiconductor layer, so as to precisely form a trench structure in the semiconductor material layer. The present application can achieve precise control of the depth of the trench etched on the semiconductor material to thoroughly avoid surface damage caused by etching and ensure that the electrical characteristic of the device is not affected by fluctuation of the etching process.