SILICON CARBIDE HIGH-VOLTAGE POWER SWITCHES

SILICON CARBIDE HIGH-VOLTAGE POWER SWITCHES

The U.S. Army Contracting Command – Aberdeen Proving Ground, Research Triangle Park Division, on behalf of the U.S. Army Research Laboratory, Sensors and Electron Devices Directorate (SEDD), is soliciting proposals for the High-Voltage Power Switches (HVPS) program under “2. MATERIALS RESEARCH (MR) CAMPAIGN, Topic L. Energy and Power, Sub-topic i. Wide Band-Gap Power Devices” of the ARL Core Broad Agency Announcement (BAA) for Basic and Applied Scientific Research, W911NF-17-S-0003. ARL is soliciting proposals under this Special Notice of the BAA for the performance of applied research focused on extending the state-of-the-art in the areas of SiC semiconductor switch design and fabrication, all for high-voltage (HV) applications. Proposals are solicited that show a path for increased current density (at high-efficiency), die size, switching frequency, and blocking voltage (>10 kV) for both low- and high-duty-cycle switches.

SiC is an emerging power semiconductor material that has electrical, thermal, and mechanical properties that allow it to far surpass the performance of conventional silicon (Si) power technology, and makes it the prime candidate for next-generation high-voltage switching devices for military, as well as commercial, applications. SiC power devices have been demonstrated to provide greater than twice the power density of Si power devices and at greater efficiency.

This program, which endeavors to advance the United States’ capability to provide SiC high-voltage high-power semiconductor switches and to identify limitations that must be overcome, builds on the success of previous high-voltage high-power SiC device programs supported by ARL, including HEPS and HVPT, which advanced the previous state-of-the-art and demonstrated performance and robustness at 10-kV and above. Technology limitations/gaps identified by this program may in turn be the focus of more sustained development efforts in the future.

Solutions are sought for the development of SiC HV (> 10 kV) semiconductor power switches and diodes, both for continuous and pulse-power applications. For continuous power, solutions are sought for either the development of single-die 10-kV to 15-kV rated metal-oxide-semiconductor field-effect transistors (MOSFETs) rated at 10 to 20 A, with or without an integrated Schottky diode—those without an integrated Schottky diode should address the reliability of the intrinsic body diode; or Insulated-Gate Bipolar Transistors (IGBTs) with single-die blocking voltages exceeding 20 kV (with a leakage current less than 10 µA), and a single-die continuous collector current greater than 30 A at a gate voltage of 20 V (with an associated collector-emitter on-state voltage less than 5 V). Additional specifications for the IGBT include an operating frequency greater than 20 kHz; robust edge terminations with dV/dt capability greater than 200 kV/µs at 18 kV; greater than 100-A short circuit capability; and chip areas larger than 1 cm2. Accompanying Junction-Barrier Schottky (JBS) diodes will require single-die blocking voltages exceeding 10 kV (with a leakage current less than 10 µA) and a current rating exceeding 30 A. In addition, the JBS diodes will need to be tuned to the IGBT turn-on characteristics for soft recovery operation. All switches considered for continuous power applications should be capable of turn-off at the maximum conduction-current rating, and be capable of reliable operation up to a junction temperature of 175 °C.

Solutions are also sought to provide compact wide bandgap pulse-power switches at the highest efficiency possible with reliable operation and ability to sustain multiple pulses in a pulse train until limiting junction temperature is attained. Thyristors and accompanying PiN diodes capable of blocking 12 kV to 20 kV DC and rated at 5 to 10 kA for pulse duty (10 µs) applications are needed to operate at high current densities (> 5 kA/cm2, total chip area) in a 70 °C ambient. These bipolar pulse devices are expected to have at least a 10,000 shot life under these conditions. Desirable device performance parameters include minimum turn-on delay and rapid spreading of transient current across the full area of large devices (low lateral impedance) for high-dI/dt applications; with uniform high-current distribution throughout the device, and consistent on-state performance from device to device. Uniformity of on-state characteristics (turn-on delay; minimum holding current; on-resistance, with a value < 30 mΩ∙cm2 at current density > 3 kA/cm2) is critical to maximizing device yield and enabling multiple devices to be packaged and switched in series and parallel configurations. Device contact metallization should be patterned such that multiple packaging options are available for experimentation (bonding, solder-based, pressure contact, etc.).

All proposals must also address the cost and availability of commercial substrates and high-quality thick epi (> 100 µm) required for these HV devices.

The Government is interested in advancing the state-of-the-art of SiC high-voltage power device technology for a wide range of applications. It is anticipated that, over the period of performance, the Applicant(s) will be able to demonstrate incremental device performance and fabrication capabilities and/or improvements thereof. As the Applicant provides device deliverables to the Government, characterizations of the switches will enable the Government to assess the state-of-the-art in HV semiconductor switch technology and provide power devices for demonstration circuits that will strive to meet Government requirements. There will be no equipment purchases using federal funds associated with awards made as a result of this Special Notice.

Funding is currently available for up to three cooperative agreements related to the HVPS program for the Fiscal Year (FY) 2018. However, the Government reserves the right to award fewer, or even no awards based on the proposals received regarding this Special Notice. While the BAA and Topic remain open for proposal submission until 31 March 2022, in order to be eligible for award under this Special Notice with the funding available for FY 2018, proposals must be received in accordance with the due dates and instructions provided in this announcement. It is anticipated that up to three cooperative agreements (31 USC 6305) will be awarded, pursuant to 10 USC 2358 Research Projects. The total amount for all awards is anticipated to be approximately $2,000,000.00 per year for up to three years subject to available funds. Proposals should include a detailed plan and budget for the first year and also anticipated work for the two option years. Cost sharing is not required under this notice. However, during the evaluation of proposals, any cost sharing will be evaluated as it relates to the evaluation factors listed in the BAA, based on the degree to which the proposed cost sharing enhances the proposal to result in added benefits to the program. To allow for evaluation of a proposed cost sharing, a proposal should express a firm commitment to provide such cost share and evidence a process for integrating the cost share into the research program.

The principal purpose of a cooperative agreement is for the public purpose of support and stimulation of fundamental research and not the acquisition of property or provision of services for the direct benefit or use of the Government. The Recipient(s) of the cooperative agreements will work collaboratively with scientists from ARL to further this SiC HVPS program.

ARL will participate in the research and use its strong in-house technical expertise (including its Device Reliability Physics, Pulse Switches and Circuit teams) to jointly plan and execute the research program with each Recipient. ARL will also evaluate the fabricated power devices to Army-specific circuit stresses and analyzing the devices’ electrical and physical response. These analyses and supporting data will be shared with the Recipient, and ways to augment the device design, process and or starting material to improve performance will be jointly determined.

In order to be eligible for a cooperative agreement under this program, Applicants are to submit proposals in accordance with the submission instructions under BAA W911NF-17-S-0003, Section II.D, no later than 6 October 2017. A Proposal submitted after this closing date will not be considered by the Government. Criteria for eligible Applicants are given in BAA, Section II.C.1. Proposals will be evaluated using the criteria listed in the BAA, Section II.E. Under this Special Notice, no formal Q&A will take place. If an Applicant has a question regarding technical clarification related to this Special Notice, contact Dr. Aivars Lelis at aivars.j.lelis.civ@mail.mil. For general assistance, contact Julia Wertley-Rotenberry at Julia.b.wertleyrotenberry.civ@mail.mil .

It is essential that you contact both Dr. Aivars Lelis and Julia Wertley-Rotenberry to inform them that a submission has been made. This Special Notice expires 6 October 2017 at 11:59 PM (EDT).