III-Nitride Semiconductor Gate Structure for Schottky Stability
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Solution Overview
Problem
Conventional III-nitride MMICs exhibit significant variations in Schottky breakdown voltage and threshold voltage at high applied voltages, along with high leakage current and poor thermal stability at high temperatures, necessitating improved Schottky behavior and thermal stability.
Innovation Solution
A semiconductor structure with a III-nitride semiconductor and a gate metal layer is engineered, featuring a conductive and non-conductive area with a gate connection line and gate contact, where the gate connection line is directly in contact with the non-conductive area, and a dielectric layer is added for insulation, enhancing stress management and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gate connection line is formed on a dielectric layer on the non-conductive area, then the Schottky contact is formed, but the Schottky performance has large variation and high leakage current at high temperature
Solution Approach 1:
The patent introduces an intermediate structure by having the gate connection line extend onto the non-conductive area of the conductive substrate. This creates a transition zone that mediates between the Schottky contact region and the insulated region, providing better electrical field distribution and reducing leakage current while stabilizing Schottky performance at high temperatures.
Solution Approach 2:
The gate connection line is extended in the planar dimension onto the non-conductive area, creating a two-dimensional configuration that distributes the electrical stress more effectively. This dimensional extension allows the connection line to serve dual functions: maintaining Schottky contact integrity and providing thermal/electrical stability at high temperatures.
2Power
If the gate contact fingers form Schottky contact on the conductive area, then the device can operate at high voltage, but the breakdown voltage and threshold voltage have large variation
Solution Approach 1:
The patent applies different structural configurations to different regions: the gate contact fingers maintain Schottky contact on the conductive area for high voltage operation, while the gate connection line extends onto the non-conductive area to provide stable electrical characteristics. This local differentiation ensures both high voltage capability and voltage consistency.
Solution Approach 2:
The gate structure is segmented into functional zones: the gate contact fingers on the conductive area handle high voltage switching, while the extended gate connection line on the non-conductive area provides stable electrical reference and reduces parameter variation. This segmentation allows each region to optimize its local function.
3Ease of manufacture
If the conventional III-nitride MMIC structure is used, then the device can be manufactured, but the thermal stability is poor at high temperature
Solution Approach 1:
The gate connection line is preliminarily extended onto the non-conductive area during the fabrication process, establishing a stable electrical configuration before the device operates at high temperatures. This preliminary structural arrangement pre-establishes the electrical field distribution that will maintain stability during subsequent high-temperature operation.
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 semiconductor structure improves Schottky performance and thermal stability by maintaining consistent threshold voltage and reducing leakage current, demonstrating enhanced reliability and stability at high temperatures and voltages.
Implementation Method 1
The at least one gate contact forms a Schottky contact with the III-nitride semiconductor on the conductive area
Implementation Method 2
a dielectric layer provided on the gate metal layer for insulation
Implementation Method 3
a source contact and a drain contact form ohmic contacts with the III-nitride semiconductor on the conductive area and coupled to the conduction channel for carrying an electric current
Data Source
AI summary
A semiconductor structure for improving the thermal stability and Schottky behavior by engineering the stress in a III-nitride semiconductor, comprising a III-nitride semiconductor and a gate metal layer. The III-nitride semiconductor has a top surface on which a conductive area and a non-conductive area are defined. The gate metal layer is formed directly on the top surface of the III-nitride semiconductor and comprises a gate connection line and at least one gate contact extending from the gate connection line in a second direction perpendicular to the length of the gate connection line. The at least one gate contact forms a Schottky contact with the III-nitride semiconductor on the conductive area, and the gate connection line is in direct contact with the III-nitride semiconductor on the non-conductive area. The non-conductive area of the III-nitride semiconductor is at least partially covered by the gate connection line.