Periodic Reporting for period 2 - FOR2ENSICS (Future Oriented Renewable and Reliable Energy SIC Solutions)
Período documentado: 2024-05-01 hasta 2025-08-31
Driven by the continued effort to combat the climate change and achieve carbon neutrality, the composition of the energy sources and consumers connected to the electrical grid is rapidly changing. An increasing amount of issues are being experienced by distribution system operators while trying to accommodate new systems like renewable energy sources or electric vehicles charging infrastructure. One of the possible solutions is to develop a DC distribution infrastructure, which is especially interesting as most of the new connections mentioned above are native DC sources and loads, respectively. This requires low cost, very efficient and compact DC/DC converters from LV (<1500V) up to MV (>10kV). However, currently no commercial solutions exist on the market. The aim of this project is to develop and demonstrate a commercial DC/DC converter prototype which can be introduced to the market within short timescale (<3 years) after completion of the project. To achieve such an ambitious target, the project team has decided to focus on the development of ultra- high voltage (UHV) SiC based switching devices which would allow for a remarkable simplification of the converter topology as well as a very compact design when coupled with high frequency operation. For this purpose, the project aims at the design, fabrication and testing of 15 kV SiC IGBTs modules. The choice of the device technology is based on previous studies, which point towards a break-even voltage between SiC MOSFET and SiC IGBT just above 10 kV. Highly relevant, both cost and environmental impact reduction of the fabrication processes will be targeted, using novel approaches for material growth and semiconductor processing. At the same time, another major
target of the project is to understand reliability issues affecting different converter components such as UHV switching devices, passive components, and medium frequency transformer associated with high switching frequency and high voltage environment.
target of the project is to understand reliability issues affecting different converter components such as UHV switching devices, passive components, and medium frequency transformer associated with high switching frequency and high voltage environment.
The overall objective of the proposal is to demonstrate disruptive Silicon Carbide (SiC) based devices with Ultra-High Voltage (UHV) capability adapted to the novel challenges of energy grid
distribution.
Here there is a summary of the objectives of the project and the grade of achievement in these first months.
Objective 1:
Description: Develop optimal SiC starting material with low defects density, high carrier lifetime and re-usable substrate adapted to 15kV bipolar devices fabrication based on an innovative substrate laser splitting technique.
Comments: Alternative process developed to fabricate the devices (see text in WP2 of the report).
%Achievement: 90%
Objective 2:
Description: Develop optimal active area and innovative termination designs for maximum current/area capability.
Comments: The design and simulation phase of the IGBT active area and termination for the first experimental batch has been completed. A conservative approach was adopted due to the anticipated higher defect density with a thicker epi layer.
% Achievement: 70%
Objective 3:
Description: Develop a processing technology based on reduced energy and water consumption, and cost reduction for SiC MOS controlled devices. A reduction by 20% fabrication costs of SiC IGBT through design and fabrication process optimization is targeted.
Comments: The KABRA process is not viable for removing the substrate in the fabrication of IGBT device wafers. Due to the required extra processing like grinding the damaged layer, it is also not a very cost effective method, especially as prices of 150mm substrates have considerably dropped during the last two years
%Achievement: 50%
Objective 4:
Description: Develop an industrial packaging solution that ensures reliable operation at 15kV and demonstrate the full potential of the SiC technology. The packaging must be non-intrusive in terms of electrical performances and parasitic circuit.
Comments: 3D Design and simulation are completed. EM Simulations enable to check margins on clearance and creepage distances, and on current density distribution.
%Achievement: 50%
Objective 5:
Description: Develop SiC IGBT packaged device with breakdown voltage above 15kV and current rating above 25A qualified to TRL5.
Comments: Test and methodology defined. All materials have been purchased . At the end of this reporting period, a total of 23 modules were manufactured and delivered to SGI, for test and implantation in the demonstrator.
%Achievement: 50%
Objective 6:
Description: Define an efficient test methodology and related test benches for UHV (>10kV) semiconductor devices and associated power electronic components used with these devices.
Comments: Milestone 1 & 3 completed.
%Achievement: 100%
Objective 7:
Description: Set up and demonstrate reliability tests methods for UHV (>10kV) devices and associated power electronic components used with these devices by means of accelerated testing and/or increased stress level.
Comments:
Task 4.1 50% achieved. Time Dependent Dielectric Breakdown (TDDB) – Constant Current Stress (CCS) tests were performed for MOSCaps on wafer level at UoB.
Task 4.2 50% achieved. HTRB tests were performed at UoB. Most of the DUTs survived far longer than 1000h. At HE cosmic ray measurements were performed.
Task 4.3 50% achieved. A Bipolar Degradation test bench has been built at UoB. First tests were performed. The tests are ongoing.
Task 4.4 40% achieved. The safe operating area and the short circuit for our 3.3kV SiC MOSFET LinPak was investigated.
Task 4.5 30% achieved .The drain leakage current was measured for the modules at 150°C and drain to sources voltage 3.3kV at Vgs = 0V
Task 4.6 45% achieved. For this task, efforts are concentrated on the Partial Discharge testing methods and the development of High Voltage and high dV/dt PD free power supplies for the excitation of samples and DUTs for the analysis of the PD inception voltage, extinction voltage and signature. Two versions of the power sources have been designed. One is based on a step up MFT and another is based on series connected SiC MOSFETs.
Objective 8:
Description: Validate performance of the packaged high voltage IGBT devices through integration in the DC/DC converter (Achieves device TRL6). Performance will be compared with MOSFETs series connection solution
Comments: Planned for 2026
%Achievement: 0%
Objective 9:
Description: Develop and validate compact DC/DC converter technology for interface between MVDC and LVDC distribution grids. Achieve 60% reduction in weight and volume compared to equivalent AC 50Hz transformer. (Achieves converter TRL5).
Comments: Conceptual design of the DC/DC converter have been developed and it is expected to achieve required reductions. The Integration has been carried out in accordance with the isolation coordination. The control is also carried out and validated in simulation environment.
%Achievement: 50%
Objective 10:
Description: Identify at least 3 use cases for early adoption of the high voltage SiC technology and DC/DC converters.
Comments: 3 Use cases have been selected and seem to be the most promising in terms of market availability.
%Achievement: 100%
distribution.
Here there is a summary of the objectives of the project and the grade of achievement in these first months.
Objective 1:
Description: Develop optimal SiC starting material with low defects density, high carrier lifetime and re-usable substrate adapted to 15kV bipolar devices fabrication based on an innovative substrate laser splitting technique.
Comments: Alternative process developed to fabricate the devices (see text in WP2 of the report).
%Achievement: 90%
Objective 2:
Description: Develop optimal active area and innovative termination designs for maximum current/area capability.
Comments: The design and simulation phase of the IGBT active area and termination for the first experimental batch has been completed. A conservative approach was adopted due to the anticipated higher defect density with a thicker epi layer.
% Achievement: 70%
Objective 3:
Description: Develop a processing technology based on reduced energy and water consumption, and cost reduction for SiC MOS controlled devices. A reduction by 20% fabrication costs of SiC IGBT through design and fabrication process optimization is targeted.
Comments: The KABRA process is not viable for removing the substrate in the fabrication of IGBT device wafers. Due to the required extra processing like grinding the damaged layer, it is also not a very cost effective method, especially as prices of 150mm substrates have considerably dropped during the last two years
%Achievement: 50%
Objective 4:
Description: Develop an industrial packaging solution that ensures reliable operation at 15kV and demonstrate the full potential of the SiC technology. The packaging must be non-intrusive in terms of electrical performances and parasitic circuit.
Comments: 3D Design and simulation are completed. EM Simulations enable to check margins on clearance and creepage distances, and on current density distribution.
%Achievement: 50%
Objective 5:
Description: Develop SiC IGBT packaged device with breakdown voltage above 15kV and current rating above 25A qualified to TRL5.
Comments: Test and methodology defined. All materials have been purchased . At the end of this reporting period, a total of 23 modules were manufactured and delivered to SGI, for test and implantation in the demonstrator.
%Achievement: 50%
Objective 6:
Description: Define an efficient test methodology and related test benches for UHV (>10kV) semiconductor devices and associated power electronic components used with these devices.
Comments: Milestone 1 & 3 completed.
%Achievement: 100%
Objective 7:
Description: Set up and demonstrate reliability tests methods for UHV (>10kV) devices and associated power electronic components used with these devices by means of accelerated testing and/or increased stress level.
Comments:
Task 4.1 50% achieved. Time Dependent Dielectric Breakdown (TDDB) – Constant Current Stress (CCS) tests were performed for MOSCaps on wafer level at UoB.
Task 4.2 50% achieved. HTRB tests were performed at UoB. Most of the DUTs survived far longer than 1000h. At HE cosmic ray measurements were performed.
Task 4.3 50% achieved. A Bipolar Degradation test bench has been built at UoB. First tests were performed. The tests are ongoing.
Task 4.4 40% achieved. The safe operating area and the short circuit for our 3.3kV SiC MOSFET LinPak was investigated.
Task 4.5 30% achieved .The drain leakage current was measured for the modules at 150°C and drain to sources voltage 3.3kV at Vgs = 0V
Task 4.6 45% achieved. For this task, efforts are concentrated on the Partial Discharge testing methods and the development of High Voltage and high dV/dt PD free power supplies for the excitation of samples and DUTs for the analysis of the PD inception voltage, extinction voltage and signature. Two versions of the power sources have been designed. One is based on a step up MFT and another is based on series connected SiC MOSFETs.
Objective 8:
Description: Validate performance of the packaged high voltage IGBT devices through integration in the DC/DC converter (Achieves device TRL6). Performance will be compared with MOSFETs series connection solution
Comments: Planned for 2026
%Achievement: 0%
Objective 9:
Description: Develop and validate compact DC/DC converter technology for interface between MVDC and LVDC distribution grids. Achieve 60% reduction in weight and volume compared to equivalent AC 50Hz transformer. (Achieves converter TRL5).
Comments: Conceptual design of the DC/DC converter have been developed and it is expected to achieve required reductions. The Integration has been carried out in accordance with the isolation coordination. The control is also carried out and validated in simulation environment.
%Achievement: 50%
Objective 10:
Description: Identify at least 3 use cases for early adoption of the high voltage SiC technology and DC/DC converters.
Comments: 3 Use cases have been selected and seem to be the most promising in terms of market availability.
%Achievement: 100%