HEMT Gate Structure With SiC Field Plate for Heat and Electric Field Balance
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Solution Overview
Problem
High electron mobility transistors (HEMTs) face challenges in achieving effective heat dissipation while minimizing electric field concentration near the gate electrode, as diamond films used for heat dissipation can be either too thin, leading to inadequate heat dissipation, or too thick, resulting in insufficient reduction of electric field concentration.
Innovation Solution
A semiconductor device configuration that includes a substrate, semiconductor layer, source and drain electrodes, a first insulating film between the electrodes, a gate electrode with a silicon carbide layer covering it, and a second portion of the gate electrode acting as a field plate, which reduces electric field concentration and enhances heat dissipation by using a silicon carbide layer with low thermal resistance and a thin first insulating film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a diamond film is provided between the gate electrode head portion and the semiconductor layer to improve heat dissipation, then heat dissipation is improved, but electric field concentration is not sufficiently reduced when the film is too thick
Solution Approach 1:
The gate electrode is divided into two distinct portions: a head portion that contacts the semiconductor layer for heat dissipation, and a second portion that extends toward the drain electrode to function as a field plate. This segmentation allows each portion to fulfill its specific function independently, resolving the contradiction between heat dissipation and electric field concentration reduction.
Solution Approach 2:
The gate electrode structure is designed to perform multiple functions simultaneously: the head portion serves as a heat dissipation path while the second portion acts as a field plate to reduce electric field concentration. This multi-functionality approach allows a single component to address both thermal management and electric field control requirements.
2Object-affected harmful factors
If the diamond film is made thin to reduce electric field concentration, then electric field concentration is reduced, but heat dissipation becomes insufficient
Solution Approach 1:
By segmenting the gate electrode into functional portions, the invention eliminates the need for a thick diamond film. The head portion provides direct thermal contact with the semiconductor layer for effective heat dissipation, while the second portion extends as a field plate to control electric fields, achieving both goals without requiring a thick intermediate film.
Solution Approach 2:
The second portion of the gate electrode acts as an intermediary field plate structure that provides electric field control without requiring a thick insulating film. This intermediary structure mediates between the heat dissipation requirement (needing thin film for thermal contact) and the electric field control requirement (needing field plate functionality).
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 configuration improves heat dissipation efficiency while effectively reducing electric field concentration near the gate electrode, allowing for better thermal management and reduced nitrogen diffusion into the silicon carbide layer.
Implementation Method 1
a silicon carbide layer covering the gate electrode... using a silicon carbide layer with low thermal resistance
Implementation Method 2
The gate electrode includes a first portion that is located within the opening in a plan view, and a second portion that is connected to the first portion, is disposed on the first film, and is located closer to the drain electrode than the first portion is... the second portion of the gate electrode acting as a field plate, which reduces electric field concentration
Data Source
AI summary
A semiconductor device includes a substrate; a semiconductor layer provided on the substrate; a source electrode and a drain electrode provided on the semiconductor layer; a first film including a first insulating film that is provided on the semiconductor layer and is located between the source electrode and the drain electrode; a gate electrode provided between the source electrode and the drain electrode; and a silicon carbide layer covering the gate electrode. The first film has an opening. The gate electrode includes a first portion that is located within the opening in a plan view, and a second portion that is connected to the first portion, is disposed on the first film, and is located closer to the drain electrode than the first portion is.