प्रकाशिक तनु फिल्म अनुभाग

Activity leader: Dr. K.M.K. Srivatsa, Sr. Principal Scientist

                           Phone: 45721075/45608609

                           Email: kmk_srivatsa@mail.nplindia.org

Name of all the team members:

  • Dr. KMK Srivatsa, Sr. Principal Scientist
  • Dr. Preetam Singh, Scientist
  • Mr. Devendra Kumar Verma, Tech. Assist.
  • Mr. Deepak Chhikara, Ph.D Student
  • Mr. Sourav Das, Research Intern

Summary of the research activity:

Current research activity is the Development of Hot-wire CVD process for the growth of polycrystalline Silicon thin films on flexible metal substrate. Our effort is focused on the Process development for large grained and thick (micron size) undoped and doped device quality polycrystalline Silicon thin films for solar cell application.


Hot-Wire CVD System:

Hot-Wire CVD (HWCVD) technique provides device quality films and can easily be scaled to large area substrates. High deposition rates and high gas utilization.

  Main Features:

  • Size of the sample – 3 inch dia.
  • Substrate heater on top of filament
  • Shower head – 4 inch diameter
  • Effective filament length – 4 inch × 4 inch
  • Separation between filament and substrate – 2 to 7  cm (variable)
  • Separation between filament and gas inlet – 1to 3 cm (variable)
  • Base Pressure –  2×10-7 Torr
  • Deposition pressure –  0.1 mTorr to 10 Torr
  • Substrate temperature –  RT to 950 oC
  • Filament temperature – RT to 2300 oC

Spectroscopic EllipsometerM/s J A Woollam, Model V-VASE:

Analysis of optical constants n, k, d values of single or multilayered thin films. Extensive modeling routines and capabilities to analyze surface roughness, inter-facial layers, graded and mixed composition films.

    Main Features:

  • Spectral range: 200 – 1700 nm
  • Variable angle of incidence: 15 – 90 degree
  • Vertical sample stage
  • Sample mapping over 150 × 150 mm area
  • Transmission & Reflection measurements

Figure: Spectroscopic Ellipsometer System

Stylus-based Surface Profiler:   M/s Ambios: Model XP-200:   

Direct measurement of thickness by step height and 3D profiling.

   Main Features:

  • Max. scan length: 55 mm
  • Stylus force: 0.03 – 10 mg
  • Vertical range: 1200 microns
  • 3D surface imaging
  • Step height standards: 50, 200, 500 nm & 1, 5 µm
  • Vibration isolation table with compressor

Figure: Stylus-based Surface Profiler System

 Deep Level Transient Spectroscopy (DLTS): M/s SULA Technologies:

For defect studies in semiconductors and semi-insulators.

Main Features:

  • Operating temperature : 80K to 730K
  • Modes of operation : Capacitance / Current DLTS and Optical DLTS

Figure: Deep Level Transient Spectroscopy (DLTS) System

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