Ridge GaN Gate Electrode Etching for Lower Gate Leak Current
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Solution Overview
Problem
HEMTs with a p type GaN gate layer experience significant gate leak current due to etching damage and electric field concentration, which are not effectively reduced by existing methods.
Innovation Solution
A method for manufacturing nitride semiconductor devices involves forming a gate electrode in a ridge shape with a two-step etching process, where the first etching step forms the upper portion of the gate electrode and the second etching step, with different conditions, forms the lower portion, thereby reducing etching damage and gate leak current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single-step etching process is used to form the gate electrode, then the manufacturing process is simple and fast, but the etching damage is severe and gate leak current is high
Solution Approach 1:
The etching process is divided into two distinct steps: a first etching step that forms the main body of the gate electrode, and a second etching step that forms the ridge portion. This segmentation allows each step to be optimized for its specific purpose, reducing overall etching damage while maintaining manufacturing efficiency.
Solution Approach 2:
The patent changes etching parameters between the two steps, using different etching conditions (such as etching gas composition, power, pressure, or temperature) to optimize the etching process for each portion of the gate electrode, thereby reducing etching damage and gate leak current.
2Reliability
If the gate electrode is formed with a ridge shape to reduce leak current, then the gate leak current is reduced, but the etching process becomes more complex
Solution Approach 1:
The gate electrode formation is segmented into two etching steps where the first step creates the base structure and the second step creates the ridge portion. This segmentation makes the complex ridge formation process more controllable and manageable.
Solution Approach 2:
The first etching step performs preliminary action by forming the main body of the gate electrode before the second step creates the ridge portion. This preliminary structure provides a foundation that simplifies the subsequent ridge formation process.
Data Source
AI summary
A method for manufacturing nitride semiconductor device includes a second step of forming, on a gate layer material film, a gate electrode film that is a material film of a gate electrode, a third step of selectively etching the gate electrode film to form the gate electrode 22 of a ridge shape, and a fourth step of selectively etching the gate layer material film to form a semiconductor gate layer 21 of a ridge shape with the gate electrode 22 disposed at a width intermediate portion of a front surface thereof. The third step includes a first etching step for forming a first portion 22A from an upper end to a thickness direction intermediate portion of the gate electrode 22 and a second etching step being a step differing in etching condition from the first etching step and being for forming a remaining second portion 22B of the gate electrode.