Roy Paily

Dr. Roy P. Paily

Professor Electronics and Electrical Engineering

Professor Centre for Nanotechnology

IIT Guwahati, Assam, India - 781039

Consultancy/Research Projects:

  1. "Securing Low Power Embedded Processors for IoT applications against Power-analysis Attacks", Semiconductor Research Corporation (SRC) India Research Program (IRP), from December 2022 until November 2025 (Principal Investigator).
  2. "Smart Wearable Advanced Nanosensing Technologies in Healthcare ASICs (SWASTHA)" Ministry of Electronics & Information Technology (MeitY), Government of India, from 31 March 2022 until 30 March 2026, (Co-Investigator at IIT Guwahati in five project deliverables 1. Affordable Wearable Anti-Microbial Electro-Stimulation Bandage for Treatment of Chronic Wounds, 2. Flexible and Wearable surfaces for monitoring muscle movement, 3. Flexible resistive random-access memories for wearable electronics, 4. Flexible resistive random-access memories for wearable electronics, 5. Development of innovative modified BST bulk composites and thin films for fabrication of smart scaffolds and thin film technology for bone tissue engineering).
  3. "Powering the Ultra-Low-Power Wireless System/IoT Node by Scavenging Multi-Band Radio Frequency (RF) Energy" jointly with BITS Pilani, Hyderabad and IIT Guwahati, SERB (Science and Engineering Research Board), Government of India, from 27 March 2021 until 26 March 2024, (Principal Investigator at IIT Guwahati).
  4. "Special Manpower Development Programme for Chip to Systems Development (SMDP-C2SD)" at IIT Guwahati, Ministry of Electronics & Information Technology (MeitY), Government of India, from 15-12-2014 till 14-11-2021, (Principal Investigator).
  5. "Centre for Excellence in Research and Development of Nanoelectronic Theranostic Devices" at IIT Guwahati, Department of Electronics & Information Technology, Ministry of Communications & Information Technology, Government of India, from 26-02-2014 till 25-02-2021 (one of the Principal Investigators).
  6. "Design and Implementation of a Blind Assistance System using FPGAs and Sensors" at IIT Guwahati, Department of Information Technology, India, from 23-11-2012 until 22-02-2017 (Principal Investigator).
  7. "Design of Carbon Nanotube Field Effect Transistor (CNFET) based Amplifiers", Global Research Collaboration (GRC) project, funded by Semiconductor Research Corporation, NC, USA, from August 2009 until July 2011 (Principal Investigator).
  8. "Special Manpower Development Project in VLSI Design and related software (SMDP II)" at IIT Guwahati, Department of Information Technology, India, from 08-11-2005 until 31-03-2013 (Investigator) (This is an Institute level project).
  9. "National MEMS Design Center at IIT Guwahati" under National Program on Micro and Smart Systems (NPMASS), from 30-12-2009 until 19-03-2013 (Principal Investigator) (This is an Institute level project).
  10. "Technology Incubation & Development of Entrepreneurs (TIDE) at IIT Guwahati in the areas of Electronics and ICT" Government of India a scheme by Ministry of Communications and Information technology by Department of Information Technology, India, from 09-06-2008 until 08-06-2010 (Principal Investigator) (This is an Institute level project and presently the project is under Technology Incubation Centre, IIT Guwahati).
  11. "Digital VLSI Design Virtual Lab", Under the National Mission on Education through ICT, from 2009 until 2012 (Principal Investigator).
  12. "Design, Fabrication and Testing of a Low Power Analog Front-End Chip for heart rate Detection", Instrument Development Division, Department of Science and Technology, India, from 29-09-2010 until 28-09-12 (Principal Investigator).

Integrated Circuit (Chip) Developments:

  1. Chip 1

    Name of the chip - SANGAI
    Technical specification – 4 Multilayer Inductors, 2.4 GHz VCO, 4 bit flash ADC, NMOS based Amplifier for GHz operation
    Foundary - UMC L180 1P6M MM/RFCMOS process of United Microelectronics Corporation (UMC) through the mini@sic programme of Europractice IC Service.
    Silicon area -1525μm×1525μm
    Test report – Test report – Two structures of outer diameters 130 μm and 222 μm and width of 8 μm were tested. The four-layer proposed structures with an outer diameter of 130 μm resulted in an inductance of 6.9 nH at 1 GHz with a peak quality factor of 6 at 2.1 GHz. In comparison, the inductor with the outer diameter of 222 μm has an inductance of 27 nH at 1 GHz with a peak quality factor of 3 at 1.1 GHz. The multilayer pyramidal symmetric inductor was implemented in the LC tank of a 2.4 GHz voltage-controlled oscillator. The measured phase noise of the VCO is -99 dBc/Hz at 100 kHz and 108 dBc/Hz at 1 MHz offset frequency with a power consumption of 5 mW. The VCO was tuned with an inversion mode PMOS varactor and it operated from 2.441 to 2.557 GHz.

  2. Chip 2

    Name of the chip - IndiaChip-Analog 3
    Participating Institutes: Jadavpur University, Kolkata and IIT Guwahati
    Chip Integrator: IIT Guwahati
    Technical specification (Designs from IIT Guwahati)– 0.5 V 480 nW preamplifier, CMOS low power Precision temperature sensor, Inductive coupled Interchip transceiver
    Foundary - UMC L180 1P6M MM/RFCMOS process of United Microelectronics Corporation (UMC) through the mini@sic programme of Europractice IC Service.
    Silicon area -1525μm×1525μm

Device Developments:

  1. Device 1

    Name of the device: Carbon Nanotube Field-Effect Transistors (CNFETs)
    Name of Sponsor: Indian Nanoelectronics User Program (INUP) at Center of Excellence in nanoelectronics (CEN) Indian Institute of Technology Bombay, India
    Investigators: K.C. Narasimhamurthy and Roy Paily
    Duration: 12-01-2010 to 21-04-2010
    Device Details: Deposition of the thin film of SWCNT on the Hafnium oxide and SiO2 layers and achieved a good nanotube density. Fabricated semiconducting carbon nanotube thin-film transistors (SN-TFT) of channel dimensions from 2 µm to 500 µm. SN-TFTs of various gate structures like the global back gate, local back gate, top gate and dual gate are fabricated. The SN-TFTs have exhibited excellent p-type output characteristics for various gate voltages. The devices have shown good subthreshold slope, on-off current ratio, transconductance and carrier mobility.

  2. Device 2

    Name of the device: High Aspect Ratio Structures Fabricated over SAW Resonator
    Name of Sponsor: Indian Nanoelectronics User's Programme, Centre for Nano Science and Engineering (CeNSE), Indian Institute of Science (IISc), Bangalore, India
    Investigators: N. Ramakrishnan, Harshal B. Nemade and Roy Paily Palathinkal
    Year: 2010
    Device Details: More than 150 SAW resonators were fabricated in three 4-inch lithium niobate wafers. SU-8 pillar structures were fabricated over the SAW patterns to study the mass loading characteristics of high aspect ratio structures. A recipe to fabricate high aspect ratio SU-8 structures on lithium niobate was identified during the project. The resonance frequency of each resonator with and without pillars was measured and the dimensions of the pillars were recorded using an optical microscope and SEM.

    3. Device 3

    Name of the device: Microhotplates for Gas Sensing Application
    Name of Sponsor: Indian Nanoelectronics User Program (INUP) at Center of Excellence in nanoelectronics (CEN) Indian Institute of Technology Bombay, India
    Investigators: Gaurav Saxena and Roy Paily
    Duration: January 2014 - May 2015
    Device Details: The microhotplate was designed at Indian Institute of Technology Guwahati and fabricated via the Indian Nanoelectronics Users Program at Indian Institute of Technology Bombay. It uses a Si/SiO₂/Si₃N₄ composite membrane, with performance improved by optimizing the insulation nitride area for better power efficiency and temperature uniformity. An analytical, modular thermal model was developed to predict temperature distribution and power consumption. The design is simple and cost-effective, requiring no additional fabrication steps; bulk micromachining defines the thin structure. The microheater features an S-shaped design (500 µm × 330 µm) with a minimum feature size of 50 µm, achieved using low-cost plastic photomasks. Devices are diced, mounted on PCB, and contacted with silver epoxy, with thermal loss minimized via PCB hole design. Temperature measurement uses K-type thermocouples + AD595 amplifier + DAQ system, with control via software and additional monitoring. Performance: At 10 V, 38 mA → 393 K (limited by epoxy failure) With direct probing: ~694 K at 175 mA The microhotplate achieves a heating efficiency of ~1.85 × 10⁻⁶ W/µm²

    Device 4

    Name of the device: PIN Photodiodes with Low Dark current for Scintillation Detection
    Name of Sponsor: Defense Research and Development Organization, Hyderabad, India
    Investigators: Dr. Amitava DasGupta, Professor, EE Dept., IIT Madras
    Duration: Defense Research and Development Organization, Hyderabad, India
    Device Details: Worked as a Senior Project Officer from 07-04-1999 till the completion of the project. The responsibilities include the design of the wafer, the design and development of the mask for PIN Photodiodes and the fabrication of the PIN diodes with the low dark current. After the successful completion of the project, complete process documents and packaged PIN diodes suitable for scintillation detection were delivered to DRDL.

    Device 5

    Name of the device: Silicon PIN Photodiodes for Detecting He-Ne Laser Signal
    Name of Sponsor: ELOIRA, RCA, Hyderabad
    Investigators: Dr. Amitava DasGupta, Professor, EE Dept., IIT Madras
    Duration: 09-07-2001 to 31-05-2003
    Device Details: Worked as a Project Officer for the project. The responsibilities include the design of the wafer, design and development of the mask for PIN Photodiodes and fabrication of the PIN diodes with the low dark current. The specifications were Dark current: < 1 nA at 12 V reverse bias, Responsivity: 0.40 A/W at 623 nm wavelength for devices with dimensions of 100 µm width and 60 µm separations. After successful completion of the project, complete process documents and packaged PIN diodes suitable for scintillation detection were delivered to ELOIRA.

    Device 6

    Name of the device: Indigenous Development of Si PIN Photodiodes
    Name of Sponsor: IISU, Indian Space Research Organization, Trivandrum, India
    Investigators: Dr. Amitava DasGupta, Professor, EE Dept., IIT Madras
    Duration: 16-04-2003 to 15-04-2004
    Device Details: Worked as a Project Officer for the project. The responsibilities include the design of the wafer, the design and development of the mask for PIN Photodiodes and the fabrication of the PIN diodes with the low dark current. The specifications were Dark current: < 1 nA at 12 V reverse bias, Responsivity: 0.40 A/W at 623 nm wavelength for devices with dimensions of 100 µm width and 60 µm separations. After the successful completion of the project, complete process documents and packaged PIN diodes suitable for scintillation detection were delivered to ELOIRA.

Sensor Developments:

  1. Sensor 1

    Name of the device: Glucose Sensor Based on Osmosis Principle without any chemical reaction
    Name of Sponsor: Indian Nanoelectronics User's Programme, Centre for Nano Science and Engineering (CeNSE), Indian Institute of Science (IISc), Bangalore, India
    Investigators: Nagesg CH and Roy Paily Palathinkal
    Duration: January 2012- May 2013
    Sensor Details: Few Sensors based on the principle of osmosis were designed and fabricated for glucose-sensing applications. The design, packaging and testing were completed at IIT Guwahati while the fabrication of devices was carried out IISc. The advantages of sensors are their chemical-free nature, better response time, improved lifetime and absence of any mechanical excitations. The device was tested with different glucose concentrations ranging from 50 mg/dL to 450 mg/dL and the output voltage of the glucose sensor was increased from -6.7 mV to 22.4 mV.

    2. Sensor 2

    Name of the device: Field Effect Transistor Based Biosensor for Detection of Glutathione
    Name of Sponsor: Ministry of Electronics and Information Technology (Government of India) and EEE Department, Indian Institute of Technology Guwahati, India. The entire work was carried out at Centre for Nanotechnology, Indian Institute of Technology Guwahati, India
    Investigators: Ujjwol Barman, Roy Paily, Siddhartha Sankar Ghosh, Department of Biosciences and Bioengineering
    Duration: January 2018 - April 2019
    Sensor Details: This work involves the design and fabrication of a biosensor for the detection of glutathione, a biomarker for cancer. The experiments include the development of an effective functionalization mechanism on ZnO nanoparticles; followed by characterization tests on fabricated chemi-resistive and FET structures for successful detection of glutathione. Sensitivity and LOD obtained were ~60 uA/dec change in concentration and ~13 nM respectively with a linear response for 100 nM - 100 mM concentration of glutathione when the device was tested for glutathione as the solution. On the other hand, when characterized with cancer cells, ~200 nA/cell of sensitivity and LOD of ~30 cells were obtained. The assay time was less than a minute. This work is expected to have a potential impact in the field of cancer applications to detect the elevated concentration of glutathione.

    Sensor 3

    Name of the device: A Surface Acoustic Wave based biosensor for the Detection of Hepatitis B Surface Antigen
    Name of Sponsor: Ministry of Electronics and Information Technology (Government of India) and EEE Department, Indian Institute of Technology Guwahati, India. The work was carried out at Centre for Nanotechnology, Indian Institute of Technology Guwahati, India
    Investigators: Namami Goswami and Roy Paily, Siddhartha Sankar Ghosh, Department of Biosciences and Bioengineering
    Duration: January 2016 - December 2019
    Sensor Details: This work presents the design, simulation, fabrication, and testing of a Surface Acoustic Wave (SAW) biosensor for detecting Hepatitis B Surface Antigen. The device uses a dual delay line configuration (one sensing, one reference) with the sensing region between electrodes. Six devices were fabricated with different electrode widths on two piezoelectric substrates. A recombinant antibody specific to HBsAg is immobilized using 11-MUA linker molecules. A novel regeneration method using acetate buffer enables reuse of the sensing surface. The sensor operates selectively in liquid medium and supports label-free detection. Best performance: 889 kHz frequency shift from a device with 4 µm IDT width on 41° YX LiNbO₃, indicating highest sensitivity. Detection range: 0.0818–818000 IU/ml, with a limit of detection ~1.5 IU/ml. The work demonstrates strong potential for advanced biosensing applications.

FPGA/Microcontroller/IoT based Developments:

  1. Project 1

    Name of the device: High-Throughput Turbo Decoder for Wireless Communication Systems
    Name of Sponsor: EEE Department, Indian Institute of Technology Guwahati, India
    Investigators: Rahul Shrestha and Roy Paily Palathinkal
    Duration: 2013 January -2014 April
    Project Details: A parallel turbo decoder with eight MAP cores was implemented on the Altera Cyclone V SoC 5CSXFC6D6F31C8ES. It decodes 6144 bits at a code rate of 1/3 in 5.5 iterations, operating at 800 MHz. JTAG interface and a virtual logic analyzer enable FPGA–PC communication, while HSMC supports high-speed data transfer (up to 3.125 Gbps). Input a-priori LLR values are stored in onboard memory; 11-bit a-posteriori LLR outputs are captured and analyzed. Hardware results were validated against MATLAB simulations. BER performance shows a 0.6 dB degradation compared to simulation at 10⁻⁴ BER for eight decoding iterations.

Process Developments:

  1. Process 1

    Name of the device: Micro-Cantilever Printing Based Devices and Applications
    Name of Sponsor: Centre for Nanotechnology and EEE Department, Indian Institute of Technology Guwahati, India
    Investigators: Vimal Kumar Singh Yadav and Roy Paily Palathinkal
    Duration: January 2018 - December 2019
    Project Details: Using Micro-Cantilever based Printing technology, micro-resistors, micro-Schottky diodes and field-effect transistors were fabricated. The print resolution and minimum feature size were in um. These resistors were cheaper compared to SMD chip resistors available in the market due to lower fabrication costs. The fabricated Schottky micro-diodes were tested as sensors for air pollutant gases such as CO2, CO and NO2 at room temperatures with a gas concentration ranging from ppb to ppm. The best sensitivity obtained was less than 1 ppb, with a response time of a few seconds and a recovery time of a couple of minutes.

System Developments:

  1. System 1

    Name of the device: Blind Assistance system using FPGAs and Sensors
    Name of Sponsor: Ministry of Electronics and Information Technology (Government of India) and EEE Department, Indian Institute of Technology Guwahati, India
    Investigators: Debajit Basak, Pralay Chakraborty, Siddhanta Roy, Nishanth PV, Monalisa Das, Satyajit Bora, Shruti Konwar, Amit Barman, Dipankar Talukdar, Jyotishman Saikia, Josephine Sylvester, Harshal Nemade and Roy Paily
    Duration: February 2011 - December 2016
    System Details:A low-cost, portable blind assistance system was developed to help visually impaired users navigate safely. It uses stereo cameras and triangulation with the ZSAD algorithm to detect obstacles and estimate distance. An object recognition module identifies humans and cars using HOG features + SVM classifiers. Navigation guidance is provided through audio feedback. Implemented on a Xilinx FPGA platform, operating at 150 MHz with ~4.02 fps and ~22.5 ms latency. Achieves ~90% detection accuracy with power consumption under 2.5 W. Successfully tested in various real-world environments (indoor, outdoor, parking). Additionally, a parking anti-collision system using ultrasonic sensors and Arduino was developed based on similar principles.

    2. System 2

    Name of the device: An FPGA /ASIC Based Sensor Platform for Monitoring Air Pollutants
    Name of Sponsor: Ministry of Electronics and Information Technology (Government of India) and EEE Department, Indian Institute of Technology Guwahati, India
    Investigators: Hari Sarkar, Deep Jyoti Das, Thockchom Birjir Singha, Shruti Konwar, Amit Barman, Gagan Deep Singh, Sandeep P., Thomas Daniel, Vimal Kumar Singh Yadav, Josephine Sylvester, Nallam Nagarjuna and Roy Paily
    Duration: December 2014 - November 2020
    Project Details: A low-cost, portable Air Quality Monitoring System (AQMS) was developed to measure CO, CO₂, NO₂, temperature, and humidity over ~100 m² areas, targeting deployment in North-East India. The system uses sensors including LM35, HiH 5030, MH-Z14, and MiCS-4514. Built around an Arduino (ATmega-based) with ADC, multiplexer (TDM), RF module, memory, LCD, and RTC. Features power-efficient operation (<1 W) using sensor duty-cycling and data buffering (MicroSD), powered by a 5 V, 11000 mAh power bank. A custom low-power Op-Amp (10-input, gain >60 dB) was designed and fabricated using TSMC 180 nm technology, meeting all target specs. The system is compact (≤20×20×15 cm), with <1 mV sensitivity, and supports periodic data acquisition (hourly). Prototype was packaged for outdoor use, tested under varying conditions, and successfully calibrated for CO, CO₂, and NO₂ at Indian Institute of Technology Guwahati.