Controller for Argon-ion gun, used for cleaning sample prior to deposition and for etching.
Several trials have been made to find out optimum settings for etching with the gun. Pieces of Si-wafers (膜；板)re used for testing. E
ach piece was covered with about 50 nm of aluminum with the e-gun.
For reasonable etch-rate and maximum area coverage settings should be:
Beam energy [kV]
Emission [mA]
Scan voltage Area1
Focus
Deflection
Pressure [mBar]
3
30
3 (max)
min (7 o'clock)
X=center, Y=near max
1.6×10-6
Optimum settings of controller for good etch-rate and maximum area coverage, focus at minimum, X-deflection at center, Y-deflection at near maximum.
On the vertical transfer rod there is a marker, angle indicator. For correct direction towards Ar-ion-gun, set to 150 degrees. For correct direction towards e-gun, for deposition, set to 0 degrees.
Marks on sample holder, one at the top for reference to mount sample holder always with this mark upwards. One area near center indicating area of good etching at above settings.
Measurements for different settings Beam energy = 3 kV Emission = 30 mA Deflection（斜，偏移，歪曲； 偏斜度，偏角）X = center, Y = near max. Time = 30 min.
View the graphs and specifications for the Model 1403 Ion Gun when working under typical conditions below.
Objective Focus Voltage vs. Working Distance
Variation of front panel focus potentiometer to produce optimum beam focus for different working distances. The two curves represent the large spot (high current) and small spot (low current) modes of operation.
Current Intensity Profile - 300nA
Beam intensity profile in small spot mode at 300nA, 5keV Ar ions. The Faraday cup used for these measurements had pinhole diameter ≈ 10µm.
Current Intensity Profile - 16uA
Beam intensity profile in large spot mode at 16µA, 5keV Ar ions. Faraday cup pinhole diameter ≈ 10µm.
Time Stability of Current
Ion beam current stability with time using a standard leak valve for gas feed. Stability over the period was <0.3%. Measurements were repeated every 10 seconds over a period of 30 minutes.
Beam Current Pressure Response
Variation of beam current with Ar gas flow rate to the ion source. The gas flow is monitored in the main chamber.
Beam Banking
Change in ion beam current as a result of applying a beam banking voltage.
Ion Gun Controllers
The NTI 1400 series Ion Gun Controllers provide power and all of the monitoring functions required to operate the Model 1401, 1403, and 1407 Ion Guns. Design features include:
Precise and stable lens voltages
Emission regulated electron impact supply
Front panel raster controls with external programmability
Power interlocks for safety and equipment protection
Remote On/Off control for automated operation from external equipment
Raster compensation electronics to correct for changes in sample geometry and working distance
Comprehensive front panel system parameter monitoring
Controller Specifications
Input Power
115/230VAC 50/60Hz auto-select operation. Fused at 3.3/1.8A.
0 - 5000V, 1mA switch mode supply continuously variable. Output voltage scales with energy. Output capacitance: 0.0047µF
Objective Focus
0 - 5000V, 1mA switch mode supply continuously variable. Output voltage scales with energy. Output capacitance: 0.0047µF
Filament Power
Emission regulated supply with front panel selectable filaments providing 5V@ 5A max.
Electron Bombardment
Electron accelerating voltage internally adjustable to 150V. Seven settings of electron emission current selectable from front panel rotary switch.
Ion Extraction
Internally adjustable to 1500V.
Deflection
Variable bi-polar 350V DC supply for +X, -X, +Y and -Y deflection. Remaining octupole elements are supplied from a resistive divider network.
Interlocks
HV cable disconnection turns off HV supplies. Adjustable high pressure interlock switches off HV supplies in the event of system overpressure. System and Auxiliary interlocks provide total shutdown in the event of system or auxiliary equipment failure
Front Panel Monitoring
Digital panel meters provide precision monitoring of all critical parameters including; lens voltages (4 1/2 digits), ion source pressure and beam current (3 1/2 digits), filament current and voltage (3 1/2 digits), emission current (3 1/2 digits).
Chassis Dimensions
483(W)x132.5(H)x435.4(D) mm. 19 inch rack-mountable desktop case 3U high.
The 1401 Ion Gun Controller comes with these additional features:
Faraday Collector for beam current measurement
The 1403 Ion Gun Controller comes with these additional features:
Dual Condenser Focus
Internally adjustable DC supply for Bend Optics
The 1407 Ion Gun Controller comes with these additional features:
Thermo Fisher Scientific produces an ion gun for virtually all applications of surface analysis. They may also be used for a variety of other vacuum. All the guns are fully bakeable and UHV compatible. Where applicable scan units are available for all guns, as well as secondary electron detectors to facilitate sample imaging.
The EX03 is an electron impact source primarily designed for sample cleaning in surface analysis experiments and is intended for use with inert gas species. Unlike the cold cathode type ion gun it can produce large currents without the inconvenience of stray magnetic fields.
Even etching One of the common requirements when cleaning samples is to have even etching across the entire surface. This is generally achieved by scanning small spot ion beams across the surface. The EX03 design can produce a flat beam profile with only small variations in current density across the beam, thus giving a low cost alternative for even sample etching.
Energy rangeThe energy range of the gun is 300 eV to 3 keV and is constantly variable over the energy range. Direct gas input into the ion source allows for a lower system operating pressure than for guns requiring backfilling of the chamber. Typical pressures at 5 x 10-6 mbar are required to achieve target currents of >20mA, with no differential pumping required.
Long working distanceThe 100mm working distance avoids clashes with other instruments inside the vacuum chamber although the optic design and focussing allow an even etch profile to be achieved at a range of working distances.
Installation
The gun is mounted on a 70mm flange allowing it to be fitted to the majority of vacuum systems. Gas inlet is via a 34mm flange on the mounting flange. The excitation source is designed to give long filament lifetimes, with the service interval increased by the presence of two filaments. All electrical connections are made through a single electrical feedthrough situated on the mounting flange on the source.
