Centre of Microsystem Technology

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MTDC (Fabrication & Growth)

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Microsystems Technology Development Centre (MTDC) - Fabrication

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The vision of MTDC is to be a leading research centre providing cutting-edge Monolithic Microwave Integrated Circuits (MMIC) and related technologies that will enhance Singapore’s defence capabilities. This platform will also enable Future Systems and Technology Directorate (FSTD) to generate intellectual property (IP) and know-hows through advanced R&D on key technologies to support the future defence needs of Singapore.

Currently under the MTDC-fabrication, the strategic areas of focus are in:

  1. Development of gallium nitride (GaN) high-electron-mobility transistor (HEMT) and MMICs,
  2. Advanced Ceramic Thin Film Filters,
  3. Diamond-on-GaN,
  4. GaN-on-Diamond,
  5. Q-Bits for Quantum Computing,
  6. and Photonic Chip Fabrication.

Apart from the above-specified key strategic topics, MTDC is also carrying out upstream research by doing collaborative research with local and international universities/ ​institutes/ companies.​

​The team has achieved the following:

  1. MTDC Facility:​
    • MTDC is certified with International Organization for Standardization (ISO) 9001: 2015 for “manufacture of semiconductor wafers and passive components on ceramic substrates”

  2. Planar AlGaN/ GaN HEMT by inert gas ion implantation:
    • Thermally stable device isolation by inert gas heavy ion implantation in AlGaN/ GaN HEMTs on Si
    • Improved planar device isolation in AlGaN/ GaN HEMTs on Si by ultra-heavy 131Xe+ Implantation

  3. AlGaN/ GaN HEMTs on Si using non-gold Metal stack:
    • Demonstration of Submicron-Gate AlGaN/ GaN HEMTs on Silicon with Complementary Metal–Oxide–Semiconductor-Compatible Non-Gold Metal Stack
    • Record-low contact resistance for InAlN/ GaN HEMTs on Si with non-gold metal
    • Conduction mechanism of non-gold Ta/ Si/ Ti/ Al/ Ni/ Ta ohmic contacts in AlGaN/ GaN HEMTs
    • Low Specific On-Resistance AlGaN/ AlN/ GaN HEMTs on High Resistivity Silicon Substrate
    • Investigation of gate leakage current mechanism in AlGaN/ GaN HEMTs with sputtered TiN

  4. Enhanced Johnson’s Figure of Merit in AlGaN/ GaN HEMTs on Si:
    • Enhanced Breakdown Voltage With High Johnson’s Figure-of-Merit in 0.3μm T-gate AlGaN/ GaN HEMTs on Silicon by (NH4)2Sx Treatment
    • High Johnson’s figure of merit (8.32THz.V) in 0.15μm conventional T-gate AlGaN/ GaN HEMTs on Si

  5. Microwave characteristics of AlGaN/ GaN HEMTs on 200mm diameter Si(111):
    • Direct Current and Microwave Characteristics of Sub-micron AlGaN/ GaN HEMTs on 8-inch diameter Si(111) Substrate
    • Uniformity Studies of AlGaN/ GaN HEMTs on 8 inch Diameter Si(111) Substrate

  6. Influence of stress in nano-channel InAlN/ GaN Fin-HEMTs:
    • Electron velocity of 6×107cm/s at 300K in stress engineered InAlN/ GaN nano-channel HEMTs
    • InAlN/AlN/GaN Triple T-shape Fin-HEMTs with gm= 646mS/mm, ION= 1.03A/mm, IOFF= 1.13μA/mm, SS= 82mV/dec and DIBL= 28 mV/V at VD= 0.5V
    • High-Frequency Microwave Noise Characteristics of InAlN/ GaN HEMTs on​ Si(111) Substrate

  7. GaN-on-Diamond HEMTs:
    • Self-heating effects in DC and RF performances of 0.25μm T-Gate AlGaN/ GaN HEMTs on Silicon and CVD-Diamond


 

Microsystems Technology Development Centre (MTDC) - Growth

Contact team

This main focus of this team is to develop III-Nitrides epitaxial growth of HEMTs heterostructures on Si and SiC substrates for high power and high frequency applications using Metal Organic Chemical Vapour Deposition (MOCVD) and Molecular Beam Epitaxy (MBE) growth techniques. Recently, this team is also aiming to develop GaN HEMTs on diamond substrate for high power applications. The III-Nitride based novel HEMTs heterostructures such as stress free barrier with better thermal conductivity buffer to enhance device performances and reliability are also being investigated. Other interesting research activities of this team include III-Nitride based intersubband quantum cascade Infrared (IR) and Ultraviolet (UV) detectors, GaN-based Gunn oscillator (self-switching diodes) and GaN HEMTs based gas sensors.

MOCVD​ and MBE based III-Nitride epitaxial growth capabilities along with non-destructive metrology tools such as high-resolution X-Ray diffraction (HR-XRD), Hall (non-contact), atomic force microscopy (AFM) and bow have been established. These epigrowth facilities are ISO 9001:2015 certified. AlGaN/ GaN HEMTs growth processes on 4 inch Si and SiC substrates with excellent properties for 0.25μm gate technology have been achieved. Key challenges in the growth of GaN HEMTs heterostructures have been overcome, such as stress mitigation layer for crack-free wafer, low buffer leakage current and high breakdown voltage. The GaN HEMTs growth process repeatability has been achieved with in-wafer and wafer-to-wafer 2DEG variation not more than 10%. The device performances show low RF loss with the state-of-the-art output power density. Other important achievements include realization of GaN-based mid-infrared and UV detectors, and gas sensors.​​​

 

Dr Subramaniam Arulkumaran
Research Director (MTDC-Fabrication) Principal Research Scientist Email: subramaniam@ntu.edu.sg Phone: +65 65927792

 

Assoc Prof Radhakrishnan K
Research Director (MTDC-Growth) Associate Professor, School of Electrical and Electronic Engineering E​mail: eradha@ntu.edu.sg Phone: +65 67904549
Dr Dharmarasu Nethaji
Programme Manager (MTDC-Growth) Senior Research Scientist Email: dharma@ntu.edu.sg Phone: +65 65927794
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