When they're gone, they're gone!
For over 20 years the Plasma Prep II system and its family have been top selling low-temperature etcher/cleaner/ashers, used in many research labs. Now the system has been replaced by the Plasma Prep III solid-state system and its family of etchers and cleaners. We will continue to sell the Plasma Prep II systems until they are gone, and we are getting close to that point. Be assured that SPI Supplies will still support these systems for as long as we can provide the RF tubes and other spare parts.
In the meantime, check out our Plasma Prep™ III Plasma Cleaner.
The SPI Plasma Prep™ Plasma Cleaner is a compact "bench top" sized plasma cleaner, that uses the "dry plasma process" for the removal of contamination on the TEM specimen holder, the sample itself, and also the part of the rod assembly for side entry goniometer stages actually seeing the high vacuum. This technology is generally thought to be applicable mainly for materials sciences investigators and not for life science investigators, or those working with polymers or other organic materials.
This is the same type of plasma cleaner instrument that was used by Dr. Nestor Zaluzec when the basic work was done that led up to the discovery that if this kind of contamination is removed, with this kind of approach, the contamination rates on samples are greatly reduced, and therefore, one sees a significant increase in the contrast and over all quality of the data in the final TEM image.
SPI Supplies manufactures and offers for sale plasma cleaning equipment for this purpose according to the terms of a license agreement granted by Argonne National Laboratory.
Sometimes there is some confusion of the terminology, that is, what is a plasma etcher vs. what is a plasma cleaner. Generally speaking, a plasma etcher is a unit that operates at 100 watts or higher but a plasma cleaner operates at power levels perhaps as low as 10 watts, but not more than about 50 watts. If your application is to remove photoresist, for example, from a silicon wafer, then what you really do need is a plasma etcher, and we would recommend our SPI Plasma Prep™ II unit.
Plasma cleaning, using a far lower power and is designed literally to "tickle" the top surface of anything is sees, so for the purpose of removing thin adsorbed layers of contamination on a TEM foil sample for example, or on the sample holder itself, a low power plasma cleaner will do the job just fine. Indeed, using argon for example, at higher power could actually "etch" and cause damage to the metal parts of the microscope stage. So if what you need is truly a plasma cleaner, read on. If not, then consider the SPI Plasma Prep™ II plasma etcher.
Insert the rod and holder assembly into the glass reaction chamber, introduce your choice of gas, either oxygen or argon or both (depending on the specimen being examined), reduce the pressure to 200 µm and apply RF power (13.56 MHz) to the chamber. This excites the gas molecules present to a highly reactive plasma state. At the 10 watt operation level, one is easily able to remove the slightly held contamination that is responsible for loss of contrast and image quality in most TEMs. Note: The primary application of this technique is for the materials scientist operating at high resolution levels and in general is not applicable to the typical life science researcher. We are always on the lookout for anyone who might furnish us such life sciences applications!
We recommend the Leybold 2.1 Cubic Feet /min pump charged with Fomblin® pump fluid.
Check out our list of Spare Parts for the SPI Plasma Prep II.™
