The main PLD vacuum chamber has the following features and components:
• 12” diameter stainless steel ultra-high vacuum electro-polished spherical chamber with multiport compatibility for PLD, 8” target carousel flange, oxygen resistance/compatible 2.2 inch dia substrate heater on 8” CF flange, process observation windows, pressure gauges, gas leak and vent, and blank ports. The ports are designed to implement future addition of in-situ RHEED, in-situ Laser reflectivity measurement, Residual gas analyzer (RGA) and load lock chamber for wafer transfer. The chamber body is fabricated from electro-polished 304 stainless steel hemispheres. The spherical chamber is bakeable to 150ºC. All port flanges are fitted with copper gaskets and a few with viton gaskets for easy chamber opening and easy laser window cleaning. Chamber is capable of reaching ultra-high vacuum (UHV) levels and leak-tested of at least 10-9 mbar-L/sec He. Blue Wave guarantees vacuum levels in the final configured system to a level better than 5×10-7 Torr which good enough for PLD thin film depositions.
• The ports are positioned in the front, back, sides, top, bottom and radially. Ports can be either closed with stainless steel flanges or optical windows. Optical view ports for optical diagnosis, or future sample manipulation, observation and monitoring of thin film growth process. All view ports are UHV compatible toughened glass windows. All components are made in USA with UHV standards. Steel frame with castor wheels for mounting the chamber with a stainless steel top and rack mount with panels.
• The PLD chamber has flange ports for substrate heater assembly, target assembly, laser ports, side view ports, vacuum gauge, in-situ optical characterization, and gas inlet.
• 5 flange ports of 8.0” inch CF, one on the top of the chamber, one at the bottom of the chamber, one in front of the chamber and two on the sides of the chamber.
• 1x 6” CF, 2 x 3.375”CF, 4 x 2.75”CF flange ports at various locations.
• 1 flange ports of 4.5” inch CF from top of the chamber pointing towards the center of the chamber closed with fused silica UV grade optical window for laser entry.
• The ports are positioned such that deposition and growth process can be monitored, analyzed with future attachments such as LRI or RHEED.
• Flange ports with fused silica UV grade optical window for laser entry.
• Substrate heater from top of the 8” CF flange port on the PLD chamber facing down to the PLD target carousel that is located on the bottom flange of the chamber. Surface of the all target in horizontal plane.
PLD Target Flange 8″ OD (CF) Mounted with Rotation Feed-through and motors. The target holder flange is capable of holding six 1” or three 2” OD targets (1/8” to ¼” thickness). PLD targets can be mounted with or without silver paste. Removable mechanical clip target holders (1” diameter x quantity 6 and 2” diameter x quantity 3) are supplied in which targets can be mounted without the use of silver paste or ink. Also included is a contamination shield which allows only one target to be exposed to the laser at a time. A motorized dual-axis magnetically coupled UHV rotary feed-through allows continuous target rotation of 10 rpm and a stepper motor allows for programmed selection of targets.
Substrate Heating Stage
The 1.6 inch or 2.0 inch diameter Inconel substrate heater is embedded with a thermocouple, electrical and thermocouple feed-through. It has the capability of reaching 950 ˚C in vacuum and reactive atmosphere (O2, NH3) up to 760 Torr (1 atm.). The assembly of the Blue Wave substrate heater is designed to be used for in-situ thermal annealing of oxide or nitride films during and after growth.
The substrate heater is a closed–loop, and the temperature non-uniformity across the wafer ranges between 2-5%. It is compatible with reactive O2, CO2, C2H2, CH4, NH3, SiH4, and metal-organic precursors, and with a vacuum of 5 x 10-8 Torr through processing gas pressure of 1 atm. A stainless steel shield/collar with 6 x 4-40 tapped holes is provided for sample clamping. An integrated inbuilt K-type thermocouple mounted from the heater’s backside approaches near the surface of the hot surface allowing for accurate temperature measurement. The heater element is sealed against exposure to reactive gases and high density plasma in the laser ablation processes. BWS substrate heater is suitable for epitaxial growth, doping, catalytic reactions, in-situ surface science as a function of temperature, and annealing of oxides, nitrides, carbides, metals, alloys, graphene, CNTs, diamond and complex multi-component and multi-layer thin films. Substrates can be attached to the heater block with silver paint or ink in order to equilibrate the temperature of the substrate in proximity of the block temperature and to minimize temperature gradient within the substrate. Blue Wave’s substrate holder also allows mechanical clamping of the substrate to avoid contamination from silver paint. Pre-ablation shutter is also included so that target can be cleaned prior to deposition on loaded substrates.
Mass Flow Controller
The system has a gas flow assembly for controlling the ambient gas as well as venting the chamber.
- It includes an MKS brand mass flow meter with digital display for O2 gas calibration to supply process gas at flow rates from 0 to 200 SCCM.
- The process pressure in the chamber during PLD can be controlled by adjusting the combination of turbo pumping speed and gas flow. A sample table for process pressure including the MKS mass flow meter rate and speed of the turbo pump will be supplied. Pressure from 10-7 Torr to 1 atm. can be easily achieved by the combination of set of parameters provided in the table. Pressure of 1 atm. can be achieved by closing the gate valve of the turbo pump.
A Variable Speed Turbo Pump manufactured by Pfeiffer (250L/sec (@N2) capacity) to achieve high vacuum more efficient than 5×10-7 Torr will be supplied. The following accessories with be added:
- Pneumatic gate valve between the chamber and turbo pump
- dry/oil free mechanical pump for backing the turbo
Gas Pressure Display: One Full Range Cold Cathode Gauge (range 1E-8 – 760 Torr (1 atm.)) and Digital Display. Pfeiffer Active Pirani/cold cathode transmitter PKR251 or similar.
Gate Valve GV- 150: Stainless steel UHV gate valve with CF150 (8″ OD) flanges. Bellow sealed shaft movement and gate viton O ring sealed. Pneumatic Gate Valve between the chamber and turbo pump.
The Blue Wave popular Heater Power supply comes with a standard Eurotherm 2416 temperature and process controller for precise heater temperature control with a precision of 1 degree. It has a PID programmable 8 segment profile including ramp, dwell, ramp, end, stop, etc. It features easy control for manual as well as auto modes. Cables and connectors are included. The temperature controller also operates with a SSR with phase angled firing.
- Eurotherm 2416 temperature controller for substrate heating with auto programing and manual modes.
- Substrate temperature control loop is closed, thermocouple and PID controller; loop control parameters can be memorized, set up during the process and loaded into any phase of the process; temperature can be programmed with a number of segments
- Precision temperature control- Control sample temperature with precision thermocouple built into the Blue Wave substrate heater.
Rated for single phase 120V/15 Amp
Blue Wave PLD set of optical components include the following components:
– 45 degree incidence angle, High reflectivity laser mirrors for 248 nm.
– High quality Plano-convex lens (50 cm focal length) for 248 nm with good focusing ability.
– mounting base plate for optics.
– Mounts and rails for mirrors, aperture, mounting rods, base plates, etc.
– Laser light protection enclosure with sliding door opaque to 248 nm laser wavelength and access to laser mirror and focusing optics.
Pulsed Excimer Laser: Excimer laser from Coherent
Coherent Laser has the following specs:
• Laser medium: KrF
• Wavelength: 248 nm
• Maximum Pulse Energy: 300-400 mJ (depending upon model and price)
• Maximum Repetition Rate: 10 Hz or depending upon model and price
• Pulse duration: 20 ns