- Design and Development of GaN HEMTs based array platform for the detection of Cancer marker:
Under CSIR Nano Biosensor Mission Project, the GaN HEMT biosensor platform is designed, developed, and packaged. The platform delivered High sensitivity (pG/ml) and high resolution (mA). The recorded O/P Current & response time were in mA and few seconds respectively.
The platform successfully tested for followings:
– Commercially available Breast cancer biomarker Her2 (Pg/ml to ng/ml)
– HER2 (ng/ml) in human serum@CCMB
– Circulatory biomarker C3G @ CCMB (using indigenously developed C3G antibody)
- Development of GaN HEMTs technology on Si:
Under the strategic sector, the team successfully completed the project with SCL Mohali on the development of the Gallium Nitride HEMT technology on Si. In this project, major gaps identified related to the unit process development on Ex situ and In situ passivated Gallium Nitride HEMT on Si substrate. Hence, we contributed in optimizations of unit process for the development of high voltage Gallium Nitride HEMT technology on Si substrate.
Few excellent results achieved are as follows:
-Ohmic contacts optimized on SCL samples. A very good contact resistivity of 2.5×10-6 (Ohms-cm2) achieved. -At 100 V, a very good isolation resistance (5×1010 Ohms/sq.) recorded. -2-terminal Burn in tests of contacts at full swing of current showed breakdown above 100 V.
-Three terminal Breakdown voltage measured up to 200 V. Devices withstand 200 V without any
problem and can go even further.
- AlGaN/GaN HEMTs based polar liquid sensor:
Under this international collaborative project, a GaN-high electron mobility transistor (HEMT) based sensor is designed, fabricated and characterized for polar liquid sensing. The fabricated HEMT sensor chip is packaged by using low temperature co-fired ceramic (LTCC) technique. The sensor shows a typical drain current of 21.2 mA at 3.3 V. The fabricated sensor shows a percentage change of 1.78%, 2.18% and 6.3% in drain current for Mercury chloride, Copper chloride and Sodium chloride respectively with respect to the drain current of pure water. The readout circuit shows a change of 0.15, 0.20 and 0.34 mA in drain current for Acetone, Water and Methanol respectively and ensures the detection of different polar liquids.
Due to the novel inter-digital structure, the sensor shows a sensitivity of 5.98 mA/mm/Debye at a drain voltage of 3.3 V. Sensing mainly depends on the dipole moment as the change in the dipole moment of the liquid changed the surface potential at the gate sensing area.
- High Frequency RF MEMS Capacitive switches:
CSIR-CEERI has developed a wide range of innovative RF MEMS devices for applications in strategic and commercial sectors including medical instrumentation and automation systems. RF MEMS switches are compact, lightweight and have superior electrical properties compared to contemporary solid state and coaxial switches. Capacitive RF MEMS switches (X & Ku band) and ohmic switches (DC to Ku band) are the basic building blocks, characterized and tested for a million cycles plus. Size, power and current handling capabilities are improved by innovative design and selection of appropriate materials like Ni-Au alloy, HfO2 and composites. In addition, single pole double throw (SPDT), single pole four throw (SP4T) switches and switch matrices are also developed. We designed and developed a novel anti-stiction RF MEMS capacitive switch for transponders for Space applications. The switches are also successfully tested at SAC-ISRO, Ahmedabad. We developed double bridge technology, first time in India for space applications to reduce the actuation voltage. Designed bio inspired low actuation voltage (<5 V) spring free technology to make it compatible for IC technology. In addition, we developed indigenous shear strength measurement of MEMS devices, Indigenous RF MEMS testing kit to characterize the ohmic SPST, SPDT and SP4T switches, Designed RF MEMS transceiver for 5G and beyond applications.
- MEMS acoustic sensor:
CSIR-CEERI has developed reliable piezoelectric MEMS acoustic sensor for high sound pressure level (SPL) measurement. An acoustic sensor exhibiting enhanced sensitivity was developed. The structure consists with a piezoelectric zinc oxide layer, sandwiched between two aluminum electrodes on a thin silicon diaphragm. The pressure compensation in the developed acoustic sensor is achieved by using a micro-tunnel development in the structure.
The measurement of high sound pressure level is an important requirement for aerospace applications because sound pressure produced by launch vehicle and large booster rocket can cause fatigue of metal panels and structures. CSIR-CEERI has developed a MEMS-based acoustic sensor for high sound pressure level (SPL) generated during Polar Satellite Launch Vehicle (PSLV) and Geosynchronous Satellite Launch Vehicle (GSLV) launching. The developed MEMS acoustic sensor chips have been delivered to Vikram Sarabhai Space Centre (VSSC), Indian Space Research Organization (ISRO) Thiruvananthapuram for their PSLV/GSLV missions. The sensor is used for monitoring the acoustic levels generated during the launch of a satellite launch vehicle. It is the first indigenously developed MEMS technology-based sensor flight-tested in an Indian Launch Vehicle and has operational heritage of 12 successive PSLV flights. The measured sensor outputs such as sensitivity, sound pressure level range and bandwidth were found to be 380 mV/Pa, 120 dB to 180 dB and 30 Hz to 8 kHz respectively. The developed acoustic sensor is a substitute of imported sensor for high SPL measurement and can also be used as a microphone. It is an emerging need of high-volume consumer communication device manufactures that are looking for acoustic sensing with the unique combination of high performance and low manufacturing cost. The markets and applications for this sensor include aero-space, defense and societal impact such hearing aids and medical applications etc.
- Design and Fabrication of Large deflection MEMS Bimorph Element for Tunable Filters:
A satellite communication payload consists of various RF components that include switches, amplifiers, filters, and other communication systems. The filter is one of the important building blocks within the communication system such as tuners and receivers that provide selectivity over a wide frequency band. For multiband systems, a payload carries a bank of pre-tuned filters resulting in a higher weight of the payload. The replacement of the filter bank by a tunable filter may significantly reduce the overall system weight, cost, and complexity. Even in ground-based receiver networks, a manual method of filter tuning to achieve the desired frequency band is a slow and cumbersome task.
To alleviate these issues, a micromachined platform can be used to replace the conventional method of filter tuning. The platform can be electrically actuated to perturb the electromagnetic field inside the micromachined cavity filter or in the proximity of the dielectric resonator to achieve the desired tenability. At CSIR-CEERI, we have developed this platform with following specifications:
1. Platform Dimension: 200μm x 200μm to 1000μm x 1000μm
2. Actuation Method: Electrothermal Actuation
3. Maximum Deflection: >50μm
4. Bimorph Layer: SiO2-Au, SiO2-Al, SiO2-Poly-Si
5. Max. no. of Segments/Bimorph: 3
6. Fabrication Method: Surface Micromachining & Bulk Micromachining
- Development of Digital Micromirror Devices for Multiobject Spectroscopy:
Multiobject Spectroscopy system of the satellite’s telescope is an important component for getting information about the elemental composition, evolution of life and presence of life on different planets. The conventional approach of MOS using slit-masks is slow, costly and results in spectral overlap and distorted information. The possibility of replacing slit-mask with micromirror array for MOS application is being explored by multiple space agencies worldwide for faster, real-time and reconfigurable target acquisition systems. On the successful development of the proposed MEMS Micromirror device, the time delay involved in the pre-imaging, data transfer and mask making will be reduced significantly. At CSIR-CEERI, we Successfully Released Micromirror in CPD and showed good LDV response of micromirror.
- Development of new generation nano metal-oxide/graphene-polymer composite materials for use in wearable electronics:
A novel flexible resistive-strain sensor based on graphene nanoplatelets (GNP)/PDMS has been developed that provides good strain sensitivity, stretchability up to 65% with a gauge factor of 62.5, indicating typical piezo-resistive characteristics. The fabricated sensor is attached to the human body, it works as a health monitoring device by detecting various human motions such as human wrist pulse measurement, the finger bending movement and in addition to the flexible pipe bending. This work presents fabrication, characterization and comparative study of four different types of GNP wrist pulse sensors. Therefore, with its simple structure and low cost processing coupled with reasonably good piezo-resistive behavior, it has great potential in wearable electronics, viz. human motion detection and health monitoring applications.
- FET-based potentiometric biosensors
FET based potentiometric biosensors are promising in the development of point of care (POC) devices for cardiac biomarkers detection in blood for health diagnostics. CSIR-CEERI has developed Silicon FET device platform for cardiac biomarkers detection in blood, which was demonstrated for troponin-I detection. Design and simulations for silicon FET platform was carried using Silvaco® TCAD tool and MATLAB®. Electrical characterization of platform device was done and repeatability analysis of the devices on same wafer was carried out. The sensing platform has been demonstrated with bio functionalization. Sensor readout with developed electronics has been demonstrated as a handheld prototype.