OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Microelectronics The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws. OBJECTIVE: The DoD is seeking a high-G rated (100 kG), low power (< 1mA @ 3V), US sourced, ceramic resonator, microelectromechanical systems (MEMS) oscillator, or crystal oscillator. This resonator, or oscillator, shall be designed to work over the military temperature range (storage -55C to 125 C; operational -40 C to 85 C), survive shock greater than 100 kG, operate under 4 kG centripetal force, smaller than 4.5mm in area, and while operating in the 4 MHz to 19 MHz range. DESCRIPTION: Fuzing applications that employ height of burst (HOB) sensors utilize either ceramic resonators or crystal oscillators to set the operating frequency and bandwidth of these systems. Historically, Ceramic Resonators were low cost, but with a large physical footprint which were acceptable for large munition HOB sensors. However, as fuzing technology is being applied to smaller munitions, the Ceramic Resonators are too large to accommodate the Size, Weight, Power, and Cost (SWaP-C) requirements while low cost crystal oscillators cannot meet the high-G rating of fuzing. Current applications show timing sources surviving peak acceleration forces of up to 65 kG for about 100us, after that the acceleration tails off exponentially. Having a clock source surviving up to 100 kG is desired. The sensitivity of quartz crystal oscillators to acceleration has been well documented [1]. Research on crystal oscillators has resulted in a quartz crystal oscillator that exhibited G-sensitivity (change in frequency resulting in acceleration force) of 2E-9/g [2]. Also, research on different MEMS oscillators have also shown low-G sensitivity [3, 4]. However, this topic requires development to be done on survival shock. PHASE I: Define whether a ceramic resonator, MEMS oscillator or crystal oscillator will be investigated. Conduct a feasibility study and design of an oscillator capable of surviving up to 100 kG. The methods and considerations for simulation of oscillators in a high-G environment shall be described. The choice of oscillator architecture and methods of microfabrication shall be defended regarding the following application-based specifications: 1. 4 MHz to 20 MHz oscillating frequency, +/- 3000 ppm. 2. 10 ms maximum start-up time. 3. 100 kG survival specification, device is inactive at time of this shock. 4. +/- 2000 ppm oscillator drift over 10 years. 5. +/- 2000 ppm temperature coefficient. 6. Operational conditions: 2.7 to 3.6 V, -40 C to 85 C, 4000 G centripetal force conditions, with +/- 2000 ppm. 7. Current consumption: < 1mA at 3V, T = 25C. The feasibility study shall detail the process and techniques used along with associated costs. If there are bulk quantity discounts factored in, the report shall disclose quantity price break points and which steps were discounted where relevant. In addition, it must include: 1. Proposed manufacturing processes flows and techniques used including dicing and etching methodologies, along with figures and diagrams describing the process. 2. Bulk material and specification (i.e., crystal orientation, dopant species, resistivity, epi thickness if any, etc.). 3. Cost break down for manufacturing compared to existing (both commercial and research) and comparative theoretical options. 4. Methodologies and analysis techniques used for characterizing the proposed device (i.e., how will you demonstrate the device will survive a 100 kG event, then operate under a 4 kG centripetal force?). The delivered report shall fully describe the proposed techniques and characterization methodologies, including a notional list of fabrication tools, facility requirements, and a program plan for follow-on phase development. If any of the above items cannot be fully addressed, the report must include relevant research and rationale that demonstrates their inapplicability to the proposed technique. If adhering to the above items is possible, but not financially feasible, the report must include relevant justification. Finally, the challenges and special considerations for testing of oscillators under high-G stress environments shall be addressed. Respondents shall deliver a report that satisfies all of the requirements outlined in Phase I. If any of the above items cannot be fully addressed in the Phase I feasibility report, the report must include relevant research and justification for their inapplicability. PHASE II: Build, test and deliver a fully functional, printed circuit board (PCB)-mountable oscillator based on the design developed in Phase I. The clock source must be able to be potted (i.e., completely covered in non-conductive polyurethane). The units will not only be potted, but also be subjected to a vacuum on the electronics to remove air bubbles. Therefore, the device must either be hermetically sealed or be able to operate covered in the non-conductive polyurethane potting. Demonstrate the capability of surviving 100 kG while adhering to the specifications outlined in Phase I. Production yields shall be considered to keep costs low with commercialization a viable option. The final report shall address manufacturing yield and reflect that the tested prototypes were selected from across multiple lots to demonstrate repeatability and quality with low variation within wafer, wafer to wafer, and lot to lot. If a non-random selection was required to optimize performance, the final report must detail reasoning for using non-random selection and the selection criteria used. Deliver a detailed final report that documents the cost breakdown per device, manufacturing processes utilized, fabrication toolset required to perform the proposed techniques, all facility requirements, and all electrical characterization and device design data (TCAD files, modeling/simulation results, etc.). If there are bulk quantity discounts factored in any of the cost breakdowns, the final report shall disclose quantity price break points and which steps were discounted where relevant. The final report shall contain sufficient technical detail such that an entity skilled in semiconductor fabrication can repeat the presented results. PHASE III DUAL USE APPLICATIONS: Other applications of this technology would be for small, low-cost embedded RAdio Detection And Ranging (RADAR) sensors for Automotive Safety, Sports Equipment, or Industrial Safety applications (which typically run with clock rates < 10 MHz), where repeated shock events may occur. REFERENCES: 1. Raymond Filler, The Acceleration Sensitivity of Quartz Crystal Oscillators: A Review IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 1988. 2. M Bloch et al, Acceleration G' Compensated Quartz Crystal Oscillators , 2009 IEEE International Frequency Control Symposium Joint with the 22nd European Frequency and Time forum, 2009 3. Bongsang Kim et al, MEMS Resonators with extremely low vibration and shock sensitivity , IEEE Sensors, 2011 4. Beheshteh Najafabadi, Study of Acceleration Sensitivity and Nonlinear Behavior in Silicon-based MEMS Resonators , Doctoral Dissertation, University of Central Florida, 2019 KEYWORDS: MEMS Resonator, Crystal Oscillator
