EXCELLENCE IN Equipment DESIGN and development FOR YOUR APPLICATION
Two vertical gradient freeze systems have been produced for a major defense sector client for production of II-IV material. These systems include growth platform and control/power supply console. These systems are flexible for process development and were designed with future capabilty of full production in mind.
System based on real time LabView OS. System handles all control functions, from process to motion to furnace.
30 SCR power controllers regulate power to each furnace zone.
In addition to soft controls on the control console, full manual controls are offered on the platform.
Bridgman platform developed for major university client. Existing furnace to be integrated into system at the Client's end. All facilities to allow for furnace integration provided. Process controls are contained in stand alone electronics case. Motion controls and thermocouple data aquistion system are PC based for integration into Client's existing control PC.
System consists of process cabinet, vertical carriage for furnace and end cap with custom seal for material processing all integrated into one platform. Vibration damping is also fitted to this system.
High vacuum end cap furnished with rotation and thermocouple feebthroughs. CFQ reactor tube and custom seal was also provided for material processing.
A custom high vacuum water-cooled elastomer seal was provided along with quartz reactor tube for low cost replaceable system for material processing.
The facilities cabinet houses the components and connections for the pneumatic, water cooling, vacuum, vent and process gas systems. This process gas system utilizes point of use purification to boost gas quality. For this system, manual valves control the process gas flow setup and pneumatic valves control the inlets and outlets into the process.
Stand alone electronics case for process monitoring and control. Motion control case that will be controlled from Client's existing control PC. Also, pictured is USB based thermocouple DAQ electronics that are connected into process end cap. This again will be utilized by existing control PC.
For this project an existing Hamco CG800 (1970's era) crystal puller was completely rebuilt into a research platform for melt replenishment Czochalski growth. The original stand and chambers were retained and virtually all other components were replaced. This included new LabView based integrated control system, stand alone temperature control/alarm system, new 60kW power supply, alarm/interlock system for process gas/cooling water and a new seed pulling mechanism. The hot zone components were also redesigned for the new application.
Puller chambers and control rack are in the foreground. 60kW power supply is visible behind the puller stand. The process gas and cooling water systems are mounted on the wall.
Integrated system control rack houses heater, motion and process controls/alarms. Systems are integrated into unfied user control though PC running LabView based software.
Panel houses the hardware temperature control and alarm. Extra space was allocated for future auxiliary heaters.
Cooling Water and Gas Flow are both vital to the safe operation of this equipment. As such, an electomechanical alarm and power interlock panel was developed to ensure safe shut-off in the event of one of these systems failing. A 4-axis servo control system was also installed with the ability to provide extreme low speed motion needed for crucible lift and crystal pulling.
Equipment being tested at high temperature.
Silicon seed being dipped during equipment testing
This platform is designed to allow for real time solidification interface tracking. It consists of two independent heaters in a vacuum chamber. A transparent crucible separates the heaters. A window into the chamber is centered on the region of crucible between the two heaters. This allows for real time tracking of the solidification interface during directional solidification. An infrared linescan camera was used to track the interface position. The platform was also design to be inserted into a 1.25T static magnetic field generator. Rotating magnetic field coils were fitted adjacent to the solidification region on the furnace insert, Hardware temperature controllers and DC power supplies power and control the heaters. A rotating magnetic field control was also developed. These elements and the linescan camera readout are integrated together on a monitoring PC using LabView based software.
The vacuum chamber containing the furnace insert and linescan camera system are visible on the left. The system control and monitoring hardware is in the rack on the right.
The furnace insert contains the material for directional solidification and the two heater units. The rotating field coils can be seen on the exterior of the insert.
View through the window into the chamber during equipment testing.
