A unique cluster tool designed and developed indigenously has all the capabilities of growing nano films and fabricating devices. It has has been implemented to fabricate

• Thin film solar cells
• Hetero junction silicon solar cells
• Tin Nano template
• Silicon Nanowires

The HWCVD cluster tool is a multichambered tool used to deposit silicon based thin films and devices. Four chambers are HWCVD reactors, one a load lock and one chamber is meant to deposit RF sputtered transparent conducting oxide (TCO) thin films.

• All the chambers are maintained at high vacuum of 10-7torr.
• Tantalum (Ta)/Tungsten (W) filaments are used to dissociate the precursor gases (resistively heated between 1500-2200 °C).
• Processing parameters such as gas flow rate, deposition pressure, substrate temperature, etc. can be set using respective controls.
• Maximum area of 10 cm x 10 cm can be deposited
• Various substrates such as glass, steel, plastic, etc. can be used.

Two single chambered HWCVD systems are housed in the lab for the deposition of silicon based alloys like silicon nitride and silicon carbon and for graphene. HWCVD silicon nitride deposited in the chamber is used as dielectric and an insulating layer. The silicon carbon films are used as dielectric barriers and etch stop layers in VLSI.

This system is used for metal deposition for electrodes/contacts on devices by thermal evaporation.

The RF magnetron sputtering system is integrated with the HWCVD cluster tool which is is used to deposit transparent conducting oxides like AZO and ITO on solar cells.

The Dektak 150 is a stylus profiler that is used to measure height differences on two-dimensional surfaces. In this system, the stylus is held statically in place and makes physical contact with the sample surface by movement of the stage front to back to measure changes in surface height.

• Provides profiling of a variety of surfaces such as thick and thin films, flexible substrates, wafers and Solar cell contact fingers etc.
• Provides precise planarity scans for measuring radius of curvature, flatness, and waviness, as well as characterizing thin-film stress on wafers.
• Provides the flexibility to perform precise step-height measurements for thin films down to 10 Å, as well as thick-film measurements up to several hundred microns thick with a step height repeatability ≤6Å
• Dektak 150 accommodates samples up to 90 mm thick, performs long scans of 55 mm. Vertical range of 524 µm with a vertical resolution of 1Å max.

QSSPC technique is very effective for determining minority charge carrier’s lifetime (τeff) of photovoltaic-grade monocrystalline and multicrystalline Silicon. It also provides with Suns-Voc tool which measures the photovoltageVOCSunsas a function of illumination.

• Flash lamp assembly having a bulb (Xenon) and a reflector
• 2 diffusers placed before the reflector
• Neutral density filters to control the intensity of light from 0.25 suns to 70.
• Sliding flash tower to vary distance between the flash and the wafer
• It measures Light Intensity (suns) and photoconductance (seimens) as a function of time
• Implied Voltage Voc as a function of light intensity
• Measured lifetime (with no Auger term subtraction) as a function of excess carrier density

• Quasi-Steady State Analysis
• Transient analysis
• Generalized Analysis.

It is a very sensitive and precise technique to determine the defect density in the amorphous and microcrystalline silicon thin films. This instrument also performs external quantum efficiency and current-voltage measurements of the solar cells.

• A Tungsten-halogen lamp (250 W) having spectrum wavelength range of 150 nm to 2500 nm is used as the excitation source.
• CPM operates in an AC mode, coupled with SR 830 Lock-in amplifier.
• CPM measures the αd value below 10^-5 (where d is the thickness of the sample).
• The sample should be a thin film of silicon with minimum thickness of 500 nm having coplanar metal electrodes with 0.5 mm of gap.
• Measurements are done at room temperature.
• A solar simulator with AM 1.5 filter (100 mW/cm²) is used for solar cell I-V measurements.

One of the most advanced and versatile wire bonders available in the institute; which can be used for bonding of Gold, Aluminum and Copper wires on the solar cells, electronic chips, sensing arrays and other semiconductor devices to make fine and precise contacts on small area.

• Can be used for Gold, Aluminum and Copper wires and ribbons.
• The diameter of wires may be 0.0007” to 0.002” and the ribbon may be up to 0.001” thick and 0.01” wide.
• Deep access option available.

• Wedge-wedge
• wedge-ball

Software and temperature controller set-up provided by Dynamic Controls, Mumbai

• Resistances from 10 Ω up to 210 PΩ & Currents from 10^-17 A to 21 mA can be measured
• Voltage from 1 μV to 210 V can be applied
• Charges from 10 fC to 2.1 μC can be measured by sourcing voltages up to ±100 V at 10 mA
• Temperature can be varied from -100 degrees to 150 degrees and can be measured up to an accuracy of +/- 1 degree
• Thin film samples with sizes up to 2 cm x 3 cm can be characterized

Resistance vs Temperature, or Current vs Temperature, or Current vs Voltage measurement.

JASCO V-530

• Light sources: Deuterium lamp for UV range (190 - 350 nm), Halogen lamp for VIS range (330 - 1100 nm)
• Light source switching: Selectable within a range of 330 to 350 nm
• Wavelength repeatability: ± 0.1 nm, wavelength accuracy: ± 0.5 nm
• Photometric modes: Abs, %T, %R
• Photometric range: -2 - 3 Abs
• Photometric reproducibility: ± 0.001 Abs (0 - 0.5 Abs); ± 0.002 Abs (0.5 - 1 Abs) ± 0.15 %T
• Wavelength scan speed: 4000, 2000, 1000, 400, 200, 100, 40 nm/min
• Wavelength slew speed: 8000 nm/min
• Baseline stability: ± 0.001 Abs/hour, Baseline flatness: ± 0.001 Abs within 200 - 1000 nm range after baseline correction
• Scan speed: 100 nm/min
• Detector: Silicon photo-diode (S1337) output port: RS-232C interface

UV/Vis/NIR spectroscopy is used to study the optical properties of thin films like reflectance, transmittance, etc.

Assembled in-house

• Four spring loaded equally spaced metal tips present on the tower. Current is applied through the two outer probes and resulting voltage is measured across the inner two probes. Tower and stage movements can be controlled manually.

Measurement of resistivity of thin film and bulk semiconductors

Nikon Optiphot 66

• HFX Microflex photomicrography system, CF Optical system
• Large rectangular, rotating mechanical stage, 50 W halogen Kohler lighting
• Nikon Reflected Light Stand with an Epi-Illuminator extension tube with 12V/50W variable lamp power supply
• Large mechanical stage with up to 6-inch travel for the 4-inch wafer holder
• Adjustable diopters ring with built-in scalar to 1-micrometre resolution
• 5X BD Plan Objective N.A. 0.10 with Polarizer
• 20X BD Plan Objective N.A. 0.25 with Polarizer
• 40X BD Plan Objective N.A. 0.65 with Polarizer
• 40X BD Plan Objective N.A. 0.90 with Polarizer

Rame-Hart Contact Angle Goniometer 230

• Contact angle measurement over solid surfaces and substrates within an error range of +/- 1 degree in ambient pressure temperature conditions.

Indigenously developed by PROVAK, Pune

• 600W RF generator (13.6 MHz) suitable for high-rate deposition with high RF power.
• Adjustable electrodes enable optimization of the distance between the electrodes to achieve uniform deposition over the wafer.
• Deposition with substrate bias.
• Precursor Evaporator (bubbler) suitable for solid and liquid precursor
• Gases available: Ar and He (Use as carrier gas).
• Substrate temperature: up to 500℃
• The system can accommodate one 4″ wafer.

PECVD is a deposition tool to deposit thin films using plasma technology. Compared to other deposition technologies such as PVD and Thermal CVD which are widely used for semiconductor device fabrication, PECVD can deposit thin films such as SiO_x, SiN_x, a-Si, BxC and DLC with high uniformity over the wafers at relatively low temperature. Currently, this system is used for BxC deposition.

Indigenously developed by PROVAK, Pune

• Planar coil generates high ion density (10¹²-10¹³ /cm³) and enables high-uniformity plasma etching over the wafers for fabrication
• Plasma generation is controlled through a separate RF power supply (1kW, 13.56Mz) while the substrate is biased through a second RF supply (300W, 13.56MHz). This enables decoupling of plasma power and substrate bias
• Height-adjustable substrate holder enables optimization of the distance between the wafer and ICP plasma source to achieve uniform plasma etching over the wafer
• Gases available: CF₄, O₂, SF₆, Ar, H₂
• The system can accommodate one 3-inch wafer

RIE system offers etching solutions of a wide variety of material including Silicon, SiO₂, SiNx compound semiconductors, metals and organics such as polymers and photoresists. The systems can control etch profile (isotropic or anisotropic) in high etch uniformity over the substrates. The system can be also used for surface treatment.

Indigenously developed by PROVAK, Pune

• The planar coil generates high ion density (10¹²- 10¹³ /cm³) and enables high-uniformity deposition over the wafers
• 1 kW RF generator (13.6 MHz) suitable for high-rate deposition with high RF power
• Low plasma potential (40-60 V) leading to less damage to substrate
• Height-adjustable substrate holder enables optimization of the distance between the wafer and ICP plasma source to achieve uniform deposition over the wafer
• Gases available: SiH₄, N₂, H₂, Ar
• Substrate temperature: up to 500℃
• The system can accommodate one 4-inch wafer

ICP CVD can be used to deposit a wide range of materials, including silicon oxide, silicon dioxide, silicon nitride, diamond like carbon, and amorphous silicon.

EST 1200 Carbolite Gero

• Furnace material: Ceramic; Ramp rate for annealing up to 5 degree/ min; Max temp. = 1200 degrees; Max Power = 0.75 kW; Minimum work tube length = 30 cm; Tube length with modified atmosphere = 60 cm; Heated length = 15 cm; Work tube diameter = 6 cm

Annealing solid samples

Ecopia HMS-3000 Hall Measurement System

• Maximum sample size: 10 mm x 10 mm
• Measurement Temperature: 300K, 77K (Liquid Nitrogen) Cool-down time: 10 sec.
• Measurement Materials: All semiconductors including Si, SiGe, SiC, GaAs, InGaAs, InP, GaN (N Type & P Type can be measured). Data input of depth enables comprehensive measurement of the whole material.
• Resistivity Range: 10^-4 to 10⁷ (Ohm-cm)
• Magnet: Permanent magnet (diameter: 50mm)
• Magnet Flux Density: 0.55 T nominal +/-1% of marked value
• Stability: 2% over 1 years
• Uniformity: +/- 1% over 20mm diameter from centre
• Pole Gap: 26 mm
• Current source: Range: 1 nA-20 mA; Compliance: 12 V
• Mobility: (cm2/Volt-sec) 1 ~ 10⁷ (including low temperature)
• Density (cm-3): 10⁷ ~ 10²¹
• Voltage measurements: Input impedance: 2x10⁷ Input voltage range: +/-12V
• Contact switching: Mechanical relays

It is a complete system for measuring the resistivity, carrier concentration, P/N type, and mobility of various materials including semiconductors (N Type & P Type) such as Si, Ge, SiGe, SiC, GaAs, InGaAs, InP, GaN, ZnO, TCOs, metals, ox-ides, etc., at both 300K and 77K. The user must supply the PC, however, all other materials needed to begin making measurements are included.

The HMS-3000 includes software with I-V curve capability to check the ohmic contact of the sample contacts.

Photo Emission Tech. Inc. (Model no. CT150AAA-EM)

• Xenon short arc lamp (1000 W) is used as the excitation source.
• Class AAA solar simulator.
• Illumination area = 156mm x 156mm, Spectral Match = +13.1% to -18.4%, Non-uniformity = 1.27%, Temporal Stability = 1.07%
• I-V curve of cell measured in four probe Kelvin system.
• Measures solar cells from 50mm x 50mm to 300mm x 300mm in size.
• Wide range of measured current values: 10 µA to 20 A.
• 16-bit measurement resolution.

• Light IV measurement
• Dark IV measurement
• Series Resistance Determination
• Cell classification and thermal coefficients of all cell parameters

Assembled In-house

• Produces strain by longitudinal displacement of up to 5 mm in the samples which can be calibrated with strain; Keithley Multimeter 2000 for measuring resistance

Gauge factor measurement