Our Technologies

Modularized High Efficiency, Low Frequency Vibration Energy Harvesting Power Supply System

A new high efficiency, low frequency, modularized vibration energy harvester system has been developed for power generation by environmental low frequency vibration or human activity. This new system design will increase the mechanical energy available for harvesting by 30x at frequencies as low as 1 Hz. A custom designed power management integrated circuit will increase the efficiency by an additional 30%. The modularized design will provide customers with a selection of power levels to satisfy various applications.

Thin Film High-k Dielectric Semiconductor Materials Development for IRFPAs

Motivation

Many emerging applications demand larger format, smaller pixel size IRFPAs (infrared focal plane) to achieve higher resolution and wider fields of view (FOV), without sacrificing existing performance which has presented a tremendous problem for today’s readout integrated circuit (ROIC) technology. The challenge is how to implement sufficient well capacity in small pixel pitch to meet sensitivity and intra-scene dynamic range requirements. Current ROICs are analog with integration capacitor taking up most of the pixel area. The ROIC designs are fabricated using the commercially available 250nm or 180nm CMOS (complementary metal-oxide-semiconductor) foundry process. Capacitors are implemented by laying poly over diffusion, poly over poly, metal over poly, or metal over metal with a thin layer of oxide grown between the two plates. To achieve higher charge capacitance density, the method of implementing MOS capacitor (using the thinner MOSFET gate oxides) is commonly used. Some foundry processes have processing options to stack MIM (Metal Insulator Metal) capacitors and/or tolerate higher voltage operations (translating into larger voltage swings) which allows for increased charge density. These standard foundry processes typically yield charge capacitive density of 4fF/um2- 6fF/um2. As we drive to smaller pixels, SiO2 can no longer meet the ROIC charge storage requirements. The goal of this effort is achieve charge density >80fF/um2 or >20X of current SiO2 based technology.

Results

In this project, MicroSol Technologies Inc. developed an innovative nanolaminated high dielectric material using Atomic Layer Deposition (ALD) for the application of IRFPAs. The process flow is compatible with 250nm and 180nm CMOS technologies with a thermal budget lower than 350°C, and chemistries used in the process present no concerns for CMOS processing. During the 5.5 month phase I base period, a capacitance density of 30 fF/ um 2 and a leakage current density of ~ 10 -5 A/cm 2 were demonstrated on planar MIM capacitors by using HfO 2 /TiO 2 nanolaminated high-k materials.

While the initial phase I objective was to develop Al 2 O 3 /TiO x nanolaminate metal insulator metal (MIM) structures, the team moved beyond this material to explore new HfO 2 /TiO 2 nanolaminates. The result was higher capacitance density and lower leakage current. Electrical performance was characterized using current - voltage (IV), capacitance - voltage (CV), and capacitance density versus frequency response. The reproducibility of capacitance density showed a non-uniformity of approximately 5%.

MIM capacitor long-term reliability was characterized by time dependent dielectric breakdown (TDDB) with a lifetime of more than 10 years for nanolaminated high-k’s. 3-D trench/hole structures were designed and fabricated by photolithography to give an area enhancement of 3-6 times. With 3-D trenches or holes, the final capacitance density should exceed 80 fF/ um 2.

During phase I research, MicroSol established a close working relationship with IR detector vendor DRS Technologies. The technical program manager from DRS Technologies’ Infrared Sensors and Systems Division, engaged in several technical discussions and one site visit to MicroSol Technologies to discuss the potential of transferring MicroSol’s high- k technology into DRS IR detectors.

3-D Integrated Hybrid Energy Harvesting and Storage Devices

Motivation

MicroSol Technologies has invented and developed a novel integrated hybrid energy harvester based on 3-D architecture. The hybrid energy harvester converts both light and electromagnetic field energy into electricity at the same time, which provides a more reliable and efficient way to enable electronic systems with self-powered function. Due to the integrated processing flow from the 3-D structure, we predict the final cost will be comparable to a single energy harvester device. We plan to commercialize our product either through licensing or manufacturing, and selling directly to customers through our foundry production (contract manufacture) model. Our potential customers include self- powered wireless sensor network (WSN) applications in the smart grid, oil and gas, and other applications such as wearable electronics and medical markets.

Results

Design and optimization of multiple antennas on the same substrate to increase the harvesting/charging efficiency. To further increase the harvesting/charging efficiency, the number of antennas and antenna design will be optimized. Also, the printed metal thickness will be optimized to maximize the output power. The critical distance between two neighboring antennas will be identified. The feasibility of stacking two layers of antennas will also be evaluated. Evaluation of thin film photovoltaic energy harvester using CIS-based materials as absorption layer. Cu/In/Se-based (CIS) materials as an absorption layer for high conversion efficiencies in the photovoltaic cells will be evaluated. CIS-based materials will be deposited by two techniques, pulsed laser deposition (PLD) and Closed space sublimation (CSS).

Developing RF-DC circuits for inkjet printed antennas. In this task, RF-DC conversion circuits will be integrated with multiple inkjet printed antennas. We will evaluate rectifier circuits by using half/full bridge diode configurations to match the antenna’s impedance with the circuit to optimize energy transferring. Finally, we will use a step-up circuit from Linear Technologies (LTC3105) to deliver a steady 5V output. This approach will minimize the size and reduce the cost of the current prototype. Programing smartphone app to display and store temperature sensor’s data. In this task, we will develop a smartphone app to display the temperature readings from the sensor node. The app will have the capability of storing a log file containing date/time information from every temperature reading. This app will provide potential customers with data to evaluate potential applications.