D-mode HEMT and MOSFET Integration for Switching Frequency
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Solution Overview
Problem
Existing HEMT power devices based on Si-GaN technology face limitations in high-frequency applications due to the need for interconnection wires between mode-conversion circuits, which reduce switching frequency and power-conversion efficiency.
Innovation Solution
Integration of a D-mode HEMT and a MOSFET conversion transistor in the same chip, eliminating the need for interconnection wires by forming the MOSFET in the substrate underneath the heterostructure layer of the D-mode HEMT, allowing the D-mode HEMT to be driven using the same driver as an E-mode transistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a D-mode HEMT is used for high-power applications, then the device can withstand high breakdown voltages and operate at high frequencies, but additional mode-conversion circuits and interconnection wires are required, which reduce switching frequency and power-conversion efficiency
Solution Approach 1:
The patent merges the D-mode HEMT power device with an E-mode conversion transistor into a single integrated device. The conversion transistor is formed in the substrate underneath the heterostructure layer of the HEMT, eliminating the need for separate mode-conversion circuits and interconnection wires. This integration allows the device to function as both a high-voltage D-mode power device and an E-mode conversion device, thereby maintaining high switching frequency while handling high breakdown voltages.
2Adaptability or versatility
If interconnection wires are used to connect mode-conversion circuits, then mode conversion is achieved, but the wires reduce power-conversion efficiency and occupy additional board area
Solution Approach 1:
The conversion transistor is integrated directly into the substrate of the HEMT device, merging the mode-conversion function with the power device. This eliminates the need for separate mode-conversion circuits and interconnection wires, thereby reducing energy loss and improving power-conversion efficiency while maintaining the necessary mode conversion capability.
3Ease of operation
If separate chips are used for control stage and power element, then functional separation is achieved, but additional interconnection wires are required, reducing efficiency
Solution Approach 1:
The patent integrates both the power device (D-mode HEMT) and the conversion transistor (E-mode) into a single chip, eliminating the need for separate chips and their associated interconnection wires. This monolithic integration maintains functional separation while removing energy losses associated with wire connections, thereby improving power-conversion efficiency.
Data Source
AI summary
The power device is formed by a D-mode HEMT and by a MOSFET in cascade to each other and integrated in a chip having a base body and a heterostructure layer on the base body. The D-mode HEMT includes a channel area formed in the heterostructure layer; the MOSFET includes a first and a second conduction region formed in the base body, and an insulated-gate region formed in the heterostructure layer, laterally and electrically insulated from the D-mode HEMT. A first metal region extends through the heterostructure layer, laterally to the channel area and in electrical contact with the channel area and the first conduction region.