| Both sides previous revisionPrevious revisionNext revision | Previous revisionNext revisionBoth sides next revision |
| pld:start [2012/02/08 14:53] – jason | pld:start [2014/08/06 10:52] – bethany |
|---|
| ====== Pulsed Laser Deposition ====== | ====== Pulsed Laser Deposition ====== |
| The PLD system comprises a ComPex 205 248-nm excimer laser plus optical elements and two vacuum chambers. It is located in Weniger 475. [[safety:start|Safety]] procedures must be observed at all times. | The PLD system comprises a ComPex 205 248-nm excimer laser plus optical elements and two vacuum chambers. It is located in Weniger 475. [[safety:start|Safety]] procedures must be observed at all times. |
| ===== Vacuum Systems===== | |
| ==== Thermionics Chamber ==== | A log of important modifications to the system can be found [[pld:changelog|here]]. If you want to know why something is the way it is, start here. |
| | |
| | ===== Thermionics Chamber ===== |
| The Thermionics chamber consists of two joined vacuum chambers, the main chamber and the load lock. The main chamber and the load lock are separated by a large gate valve which serves to isolate the two sections. The load lock and the main chamber are each served by two vacuum pumps, a turbo-molecular pump and a roughing pump working in series. | The Thermionics chamber consists of two joined vacuum chambers, the main chamber and the load lock. The main chamber and the load lock are separated by a large gate valve which serves to isolate the two sections. The load lock and the main chamber are each served by two vacuum pumps, a turbo-molecular pump and a roughing pump working in series. |
| |
| === Roughing Pump === | === Roughing Pump === |
| |
| The main chamber roughing and turbo pumps are manufactured by BOC Edwards. Like the Alcatel roughing pump, the oil should be changed every 6 months. However, it is essential that the oil **is not hydrocarbon oil**. The replacement oil **must be Krytox 1506** or Fomblin 06/6. The use of Krytox 1506 is preferred since the Fomblin type oils tend to leak and seep through seals in the pump, while the Krytox will not. Typically, Krytox is sold by mass rather than by volume like most other oils. To successfully change the oil, 3kg are needed. As of 5/25/2011 Krytox 1506 costs ~$200/kg. | The main chamber roughing and turbo pumps are manufactured by BOC Edwards. Like the Alcatel roughing pump, the oil should be changed every 6 months. However, it is essential that the oil **is not hydrocarbon oil**. The replacement oil **must be Krytox 1506** or Fomblin 06/6. The use of Krytox 1506 is preferred since the Fomblin type oils tend to leak and seep through seals in the pump, while the Krytox will not. Typically, Krytox is sold by mass rather than by volume like most other oils. To successfully change the oil, 3kg are needed. As of 5/25/2011 Krytox 1506 costs ~$200/kg. 8/2014: Krytox 1506 costs $2,500/gal = $312.50/kg @ 8kg/gal. We use about 3kg/year. Krytox 1506 can be obtained about 6x more cheaply by **recycling** our used Krytox - approx $400/gal - from Kurt Lesker (2 gal minimum) or Ideal Gas (1 gal minimum). |
| |
| Do not mix these PFPE oils with hydrocarbon oils; if this happens the pump must be cleaned according to the manual's instructions as these oils are not compatible. This means that they are not soluble in one another, and the material properties will change across the interface, foaming may occur, and the pump will not be properly lubricated. Krytox is used because it is highly resistant to attack by oxygen or corrosive process gasses. **DO NOT EVER USE OXYGEN PROCESS GAS WITH HYDROCARBON OILS!** | Do not mix these PFPE oils with hydrocarbon oils; if this happens the pump must be cleaned according to the manual's instructions as these oils are not compatible. This means that they are not soluble in one another, and the material properties will change across the interface, foaming may occur, and the pump will not be properly lubricated. Krytox is used because it is highly resistant to attack by oxygen or corrosive process gasses. **DO NOT EVER USE OXYGEN PROCESS GAS WITH HYDROCARBON OILS!** |
| The BOC Edwards Turbo pump is an amazing, maintenance-free, wonder pump. This pump has a low pressure limit of 10^-9 Torr, and has magnetic bearings so that there is no hydrocarbon grease vaporizing into the chamber. If the turbine were to suffer an unbalanced build up of matter on it, changing its moment of inertia, the controller will modify the bearing properties along 5 axes (3 translational, 2 angular) such that the turbine always rotates about its center of mass in a balanced way. When the entire system is clean, this pump easily matches it's operating pressure specs, and at times surpasses them. | The BOC Edwards Turbo pump is an amazing, maintenance-free, wonder pump. This pump has a low pressure limit of 10^-9 Torr, and has magnetic bearings so that there is no hydrocarbon grease vaporizing into the chamber. If the turbine were to suffer an unbalanced build up of matter on it, changing its moment of inertia, the controller will modify the bearing properties along 5 axes (3 translational, 2 angular) such that the turbine always rotates about its center of mass in a balanced way. When the entire system is clean, this pump easily matches it's operating pressure specs, and at times surpasses them. |
| |
| ====Power Outages==== | ==== Substrate heating ==== |
| The Thermionics chamber is set up so that in event of a power failure, the valves between the roughing and turbo pumps will remain closed and the pumps will not turn back on when power is restored. | FIXME Chris |
| |
| If you discover that the power has gone out while the pressure is still fairly low (10<sup>-3</sup> Torr), you can use {{:pld:thermionicsreset.pdf|these instructions}} to pump the system down. If the pressure is too high, then start the system up normally after restoring power to the pumps and TMP controllers (toggle switch up on silver panel, reset buttons on black panels - check fuses if nothing happens). | ===== Neocera Chamber ===== |
| | FIXME |
| | ==== Substrate heating ==== |
| | FIXME |
| | =====Power Outages===== |
| | //Thermionics chamber//: The Thermionics chamber is set up so that in event of a power failure, the valves between the roughing and turbo pumps will remain closed and the pumps will not turn back on when power is restored. |
| | |
| | If you discover that the power has gone out while the pressure is still fairly low (10<sup>-3</sup> Torr), you can use {{:pld:thermionicsreset.pdf|these instructions}} to pump the system down. If the pressure is too high, then start the system up normally after restoring power to the pumps and TMP controllers (toggle switch up on silver panel, reset buttons on black panels - check fuses if nothing happens). [[pld:pld_control_panel_tower|Here]] is a schematic for reference |
| |
| The Edwards roughing pump on the main chamber frequently fails to start. If this happens, unplug it from the gray power strip and plug it directly into the wall. Let it run for a few minutes and then plug it back into the power strip and try to turn it on again. | The Edwards roughing pump on the main chamber frequently fails to start. If this happens, unplug it from the gray power strip and plug it directly into the wall. Let it run for a few minutes and then plug it back into the power strip and try to turn it on again. |
| |
| | //Neocera chamber//: |
| | FIXME |
| |
| |
| |
| ==== Windows ==== | ==== Windows ==== |
| There are many windows on the thermionics chamber. However, there are two UV grade laser windows. Each of these is mounted in a ConFlat flange. Each of the laser windows is made of fused silica, and measuring with the Coherent power meter, have a loss of approximately 10%. | There are many windows on the thermionics chamber. However, there are two UV grade laser windows. Each of these is mounted in a ConFlat flange. Each of the laser windows is made of fused silica, and measuring with the Coherent power meter, have a loss of approximately 10% at 248nm. |
| |
| ===== Procedure ===== | ===== Procedure ===== |
| |
| {{:pld:neocera.pld.instructions.pdf|Neocera Chamber}} | {{:pld:neocera.pld.instructions.pdf|Neocera Chamber}} |
| | |
| | {{:pld:gas_change_20120606.pdf|Laser Gas Change}} |
| |
| ===== Routine Maintenance ===== | ===== Routine Maintenance ===== |
| | The maintenance schedule for the PLD lab is located [[pld:maint_sched|here]]. |
| | |
| FIXME | FIXME |
| Vacuum inside of laser cabinet (monthly) | Vacuum inside of laser cabinet (monthly) |
