High Power Semiconductor Device Schottky Contact Segmentation
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Solution Overview
Problem
High electron mobility transistors face premature breakdown due to strain at Schottky metal contacts and defects that generate leakage currents, limiting their breakdown voltage and operational reliability.
Innovation Solution
A high power semiconductor device design featuring two diodes electrically connected in parallel and a Schottky contact on a channel layer to reduce turn-on voltage and resistance, increasing breakdown voltage by forming a trench that exposes the channel layer and creating a connecting portion for electrical connection and Schottky contact, thereby lowering Schottky barrier and turn-on resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If Schottky metal contacts are used in high electron mobility transistors, then high current density and frequency operation are achieved, but strain at contact edges causes defects and leakage currents that limit breakdown voltage
Solution Approach 1:
The gate contact structure is segmented into multiple regions: a main gate contact region and a separate gate edge contact region. This segmentation allows different materials and structures to be used in different regions, reducing strain concentration at the contact edges while maintaining high current density in the main contact area.
Solution Approach 2:
Different material compositions and structures are applied to different regions of the gate contact. The main gate contact uses a material optimized for low resistance, while the gate edge contact uses a material or structure optimized for reducing strain and preventing defect formation. This local differentiation resolves the contradiction between high current density and high breakdown voltage.
2Power
If higher concentrations of two dimensional electron gases are formed to increase current density, then higher current density is achieved, but defects occur due to strain and high electric field that generate leakage currents
Solution Approach 1:
An intermediate gate edge contact structure is introduced between the high electric field region and the metal contact. This intermediate structure acts as a mediator that gradually transitions the electric field and strain distribution, preventing the formation of defects and leakage currents while allowing high current density to be maintained in the main contact region.
3Ease of operation
If high electric field is concentrated at edges of Schottky metal contacts to enable operation under drain-to-gate threshold voltage, then transistor operation is enabled, but defects occur due to strain that become deep-level traps generating significant leakage currents
Solution Approach 1:
The gate contact is segmented into a main contact region that handles high current density and a separate gate edge contact region that manages the electric field at the threshold voltage operation point. This segmentation allows the edge contact to be optimized for low-strain operation while the main contact maintains high conductivity.
Solution Approach 2:
The material parameters (composition, thickness, doping) of the gate edge contact are specifically changed to reduce strain and electric field concentration. By adjusting these parameters, the contact can operate effectively at threshold voltage without generating the defects that lead to leakage currents and reduced breakdown voltage.
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 design enhances the breakdown voltage and reduces turn-on resistance, improving the operational reliability and current handling capacity of high power semiconductor devices by effectively managing electric field stress and leakage currents.
Implementation Method 1
a connecting portion covering the bottom wall of the trench, electrically connected with the second electrode and the fourth electrode, and forming a schottky contact with the third region of the channel layer
Implementation Method 2
a heterostructure consisting of an aluminum gallium nitride layer and a gallium nitride layer that can cause a spontaneous polarization and a piezoelectric polarization
Implementation Method 3
a heterostructure consisting of an aluminum gallium nitride layer and a gallium nitride layer that can cause a spontaneous polarization and a piezoelectric polarization
Data Source
AI summary
This application provides a high power semiconductor device, which is characterized by forming two diodes connected in parallel and a schottky contact on a channel layer to lower the turn-on voltage and turn-on resistance of the high power semiconductor device at the same time and to enhance the breakdown voltage.