溅射离子泵的发明历史
离子泵的名词解释：
离子泵（溅射离子泵）是一种类型的真空泵，
溅射离子泵的名词解释
溅射离子泵的工作原理
溅射离子泵的应用场所
以下内容取自维基百科及Agilent官网：
An ion pump (also referred to as a sputter ion pump) is a type of vacuum pump which operates
by sputtering a metal getter.
Under ideal conditions, ion pumps are capable of reaching pressures as low as 10−11 mbar.
An ion pump first ionizes gas within the vessel it is attached to and employs a strong electrical
potential, typically 3–7 kV, which accelerates the ions to into the a solid electrode.
Small bits of the electrode are sputtered into the chamber.
Gasses are trapped by a combination of chemical reactions with the surface of the
highly-reactive sputtered material, and being physically trapped underneath that material.
溅射离子泵的发明历史：
The first evidence for pumping from electrical discharge was found 1858 by
Julius Plücker, who did early experiments on electrical discharge in vacuum tubes.
In 1937, Frans Michel Penning observed some evidence of pumping in the operation of
his cold cathode gauge.
These early effects were comparatively slow to pump, and were therefore not
commercialized. A major advance came in the 1950s, when Varian Associates were
researching improvements for the performance of vacuum tubes, particularly on
improving the vacuum inside the klystron. In 1957, Lewis D Hall, John C Helmer,
and Robert L Jepsen filed a patent.
for a significantly improved pump, one of the earliest pumps that could get a vacuum
chamber to ultra-high vacuum pressures.
Ultra-High Vacuum Pump
10-7Pa （或10-9mbar）以下的真空度称之为Ultra-high Vacuum (UHV)
Typically, UHV requires:
High pumping speed — possibly multiple vacuum pumps in series and/or parallel
Minimize surface area in the chamber
High conductance tubing to pumps — short and fat, without obstruction
Use low-outgassing materials such as certain stainless steels
Avoid creating pits of trapped gas behind bolts, welding voids, etc.
Electropolish all metal parts after machining or welding
Use low vapor pressure materials (ceramics, glass, metals, teflon if unbaked)
Bake the system to remove water or hydrocarbons adsorbed to the walls
Chill chamber walls to cryogenic temperatures during use
Avoid all traces of hydrocarbons, including skin oils in a fingerprint — always use gloves
Hydrogen and carbon monoxide are the most common background gases in a well-designed,
well-baked UHV system. Both Hydrogen and CO diffuse out from the grain boundaries in
stainless steel. Helium could diffuse through the steel and glass from the outside air,
but this effect is usually negligible due to the low abundance of He in the atmosphere.
Ultra-high vacuum is necessary for many surface analytic techniques such as:
X-ray photoelectron spectroscopy (XPS)
Auger electron spectroscopy (AES)
Secondary ion mass spectrometry (SIMS)
Thermal desorption spectroscopy (TPD)
Thin film growth and preparation techniques with stringent requirements for purity, such as
molecular beam epitaxy (MBE), UHV chemical vapor deposition (CVD), atomic layer
deposition (ALD) and UHV pulsed laser deposition (PLD)
Angle resolved photoemission spectroscopy (ARPES)
Field emission microscopy and Field ion microscopy
Atom Probe Tomography (APT)
UHV is necessary for these applications to reduce surface contamination, by reducing
the number of molecules reaching the sample over a given time period. At 0.1 mPa
(10−6 Torr), it only takes 1 second to cover a surface with a contaminant, so much
lower pressures are needed for long experiments.
UHV is also required for:
Particle accelerators The Large Hadron Collider (LHC) has three UH vacuum systems.
The lowest pressure is found in the pipes the proton beam speeds through near the
interaction (collision) points. Here helium cooling pipes also act as cryopumps. The maximum
allowable pressure is 10−6 Pa (10−8 mbar)
Gravitational wave detectors such as LIGO, VIRGO, GEO 600, and TAMA 300. The LIGO
experimental apparatus is housed in a 10,000 m3 (353,000 cu.ft.) vacuum chamber at
10−7 Pa (10−9 mbar) in order to eliminate temperature fluctuations and sound
waves which would jostle the mirrors far too much for gravitational waves to be sensed.
Atomic physics experiments which use cold atoms, such as ion trapping or making
Bose–Einstein condensates
and, while not compulsory, can prove beneficial in applications such as:
Molecular beam epitaxy, E-beam evaporation, sputtering and other deposition techniques.
Atomic force microscopy. High vacuum enables high Q factors on the cantilever oscillation.
Scanning tunneling microscopy. High vacuum reduces oxidation and contamination, hence
enables imaging and the achievement of atomic resolution on clean metal and
semiconductor surfaces, e.g. imaging the surface reconstruction of the unoxidized silicon surface.
Electron-beam lithography
UHV System design:
There is no single vacuum pump that can operate all the way from atmospheric pressure to
ultra-high vacuum. Instead, a series of different pumps is used, according to the appropriate
pressure range for each pump. In the first stage, a roughing pump clears most of the gas from
the chamber. This is followed by one or more vacuum pumps that operate at low pressures.
Pumps commonly used in this second stage to achieve UHV include:
Turbomolecular pumps (especially compound and/or magnetic bearing types)
Ion pumps
Titanium sublimation pumps
Non-evaporable getter (NEG) pumps
Cryopumps
以上就是溅射离子泵的发明历史简介，同时对UHV系统的描述
