Plasma IBEAM FC User manual

PLASMA PROCESS GROUP, INC.
IBEAM FC / FN
Ion Beam Source Power Supply Manual
DC Filament Cathode / Filament Neutralizer

Copyright 2009, 2015 by Plasma Process Group, Inc. All rights reserved
7330 Greendale Road, Windsor, CO 80550
Phone [phone] • Fax [phone]
No part of this publication may be reproduced without prior written permission
Date: May, 2015 v2.0

Table of Contents
Chapter 1: Introduction . . . . . . . . . . . . . 1
1.1: Description . . . . . . . . . . . . . 2
1.2: Limited warranty . . . . . . . . . . . . 3
1.3: Service and Technical Contact Information . . . . . 4
1.4: Warning Statements . . . . . . . . . . . 5
Chapter 2: Theory of Operation . . . . . . . . . . . 6
2.1: Source Parameter Definitions . . . . . . . . . 10
2.2: Ion Beam Properties . . . . . . . . . . . 14
2.3: References . . . . . . . . . . . . . . 16
Chapter 3: Set up and Installation Procedures . . . . . . . . 17
3.1: Connections layout / Input power specifications . . . . 18
3.2: RS232 communications / Remote switch connections . . 19
3.3: Output: Source and neutralizer . . . . . . . . 20
3.4: Mounting and air cooling . . . . . . . . . . 21
3.5: Electrical Connection Setup . . . . . . . . . 22
Chapter 4: Operation . . . . . . . . . . . . . . 23
4.1: Power Supply Layout . . . . . . . . . . . 23
4.2: Keypad entry and power supply adjustments . . . . . 24
4.3: User interface examples . . . . . . . . . . 27
4.4: Mode indicator and adjustments . . . . . . . . 29
4.5: Beam/Source On/Off. . . . . . . . . . . 31
4.6: Operation example . . . . . . . . . . . 32
Chapter 5: Remote Control . . . . . . . . . . . . 37
5.1: RS232 communications . . . . . . . . . . 37
5.2: Command details . . . . . . . . . . . . 40
5.3: Operation example . . . . . . . . . . . 48
5.4: Remote switches . . . . . . . . . . . . 49
Chapter 6: Troubleshooting . . . . . . . . . . . . 50
6.1: Power supply error codes . . . . . . . . . . 51
6.2: Starting the source . . . . . . . . . . . . 52
6.3: Turning on the beam . . . . . . . . . . . 53
6.4: Neutralizer operation . . . . . . . . . . . 54
6.5: Special testing . . . . . . . . . . . . . 55
Chapter 7: Specifications . . . . . . . . . . . . . 57

D C I O N B E A M S O U R C E P O W E R S U P P L Y
1
Introduction
Thank you for purchasing an ion beam source power supply from Plasma Process Group!
This Manual covers the installation and operation of our IBEAM 601 FC/FN power supply. The
I-BEAM™ power supply is designed to control a DC style ion beam source.
Ion beam technology was developed at NASA in the 1960’s as a means of producing thrust on
spacecraft. Several spacecraft have used ion beam thrusters for station keeping and trajectory
control. The spacecraft Deep Space 1, demonstrated the long duration performance capabilities and
propulsion advantages of ion-beam thrusters. There are numerous publications about ion beam
thrusters and some are given here for the interested reader [1-3].
Ion beam sources also have numerous terrestrial applications. In the past decades, ion beams have
been used for depositing wear resistant diamond-like carbon coatings on mechanical and optical
hardware. They have also been used to fabricate the read/write heads used in computer hard-drives
and thin-film optical filters for telecommunication applications. A select few publications involving
ion beam deposition technology are given here for the interested reader [4-7].
For this manual, it is assumed the operator of the ion beam source has a basic knowledge and/or
technical skills with electrical discharge devices. If necessary, we encourage a review of the
introductory chapters for the following references [8-10]. A basic physical knowledge of plasma
behavior is required: however, the mathematical descriptions will be kept to a minimum. For any
technical assistance, please contact us.
We at Plasma Process Group hope that using your new ion beam source will produce rewarding
results.
Chapter
1

2
Section 1.1: Description
The I-BEAM™ FC/FN Power Supply provides power and control for ion beam sources with
filament cathodes and filament neutralizers. Designed especially to optimize performance of Plasma
Process Group's 3cm and 8cm ion beam sources, the I-BEAM™ FC/FN can run sources from
other manufacturers as well.
For production applications, the I-BEAM™ FC/FN is designed for reliability and ease of use.
Control modes allow operation from the front panel, or remotely through the RS-232 interface. In
remote control mode, operating parameters are set via the interface. In local control mode, the
power supply adjusts parameters automatically, based on preset values, minimizing operator
intervention or error. Up to 9 sets of operating parameters can be stored in the I-BEAM™ FC/FN.
The I-BEAM™ FC/FN is also well suited for research & development applications. A separate
display and keypad make setup and operation quick and easy. All ion source operating parameters
are displayed continuously on individual large LED displays. Manual control mode gives the
operator full control of all parameters, to respond to those unexpected circumstances typical of
research.

3
Section 1.2: Limited Warranty
Our workmanship warranty:
All equipment manufactured and sold by Plasma Process Group Inc is warranted to be free of
defects and workmanship when shipped. The latest copy of our warranty statement can be obtained
on our website www.plasmaprocessgroup.com/itemdocs/tech/Terms_and_conditions.pdf .
The warranty on all equipment is for one year commencing (a) on final acceptance or (b) 30 days
from shipping, whichever occurs first. This warranty covers the cost of parts and labor.
Expendable and consumable items, such as grid assemblies, RFN collectors and discharge chambers
are excluded from this warranty. This warranty supersedes all other warranties, expressed or
implied. Plasma Process Group Inc assumes no contingent liability for damages or loss of
production.
Expendable items, including, but not limited to, grid assemblies, RFN collectors, discharge
chambers, filaments, fuses, o-rings and seals are specifically excluded from the foregoing warranties
and are not warranted.
Seller assumes no liability under the above warranties for equipment or system failures resulting
from (1) abuse, misuse, modification or mishandling; (2) damage due to forces external to the
equipment including, but not limited to, flooding, power surges, power failures, defective electrical
work, transportation, foreign equipment/attachments or Buyer-supplied replacement parts or
utilities or services such as process gas; (3) improper operation or maintenance or (4) failure to
perform preventative maintenance in accordance with Seller's recommendation (including keeping
an accurate log of preventative maintenance). In addition, this warranty does not apply if any
equipment or part has been modified without the written permission of Seller.

4
Section 1.3: Technical Contact Information
For Service or Repair contact:
Plasma Process Group Inc (PPG)
www.plasmaprocessgroup.com
Please supply the following information:
Product
Model and serial number
Date Purchased
Detailed description of problem
Contact person
If the product is to be returned to PPG for repair you will be assigned a Return Authorization
number (RA), warranty status of the equipment and shipping information to return the product.
The RA number should be attached to the outside of the shipping container. A purchase order
number should be included should the equipment not be under warranty. After PPG receives the
equipment a firm quote and estimated repair time will be given prior to work being started.

5
Section 1.4: Warning Statements
WARNING
This symbol illustrates a voltage hazard.
CAUTION
This symbol is used to warn of a potential voltage hazard.
WARNING
This symbol is used to warn of electrocution hazard.
WARNING
This symbol is used to warn of a HIGH VOLTAGE hazard.
Warning –Risk of Injury to Persons
This symbol is used to warn of a heavy lift operation.
WARNING –This symbol is used to warn of a potential hazard.
Chapter

6
Theory of Operation
The function of an ion beam source is to produce ions and accelerate these ions to high velocities so
they are ejected downstream from the source. The ejected ions are directed to form a “beam” in
which the ions are mono-energetic with velocities on the order of km/s. An ion beam source
consists of four (4) key elements:
Discharge Chamber, Electron Source, Grids, and Neutralizer
Presented in Figure 2.1 is a schematic of an ion beam source. Basically, the source is operated by
introducing the source gas into the discharge chamber. An electron source is used to ionize the
gas and establish a plasma. Recall, a plasma is an electrically conductive gas where the density of
ions and electrons are approximately equal. Ions created in the discharge chamber are then
accelerated to high velocities with the source grids. A neutralizer is placed downstream from the
source where it emits electrons to balance the number of positive ions which leave the source.
Figure 2.1: Schematic of an ion beam source.
Chapter
2

7
The different types of ion beam sources are delineated by the specifics of the four (4) key elements.
In this introduction, ion beam sources will be classified as either direct current (DC) or radio
frequency (RF). A brief, physical description of each of the four elements is presented below.
Discharge Chamber: The discharge chamber is where the source gas is ionized
For DC sources, the discharge chamber is referred to as the body. The body will have a magnetic
field produced using permanent magnets. The purpose of the magnetic field is to control the
motion of electrons such that they have several ionizing collisions with the source gas occur before
being collected on the anode.
For RF sources, the discharge chamber consists of a dielectric material permeable to the RF field
produced by the antenna. The RF field ionizes the source gas introduced within the discharge
chamber.
Electron Source: Mechanism by which electrons are produced to ionize the source gas.
For DC sources, the electron source can be either a hot filament or a hollow cathode. Typically, a
filament consists of a tungsten wire which is heated to emit electrons. A hollow cathode is a device
which produces electrons by locally ionizing its own feed gas. The electrons from either the
filament or hollow cathode are then used to ionize the source gas, which, for the hollow cathode
case, may be the same gas it used. The electrons have several ionizing collisions before being
collected at the anode surface in a DC source.
For RF sources, the RF field energizes free electrons in the working gas. The energetic electrons
have ionizing collisions with the source gas thereby producing ions and additional electrons. As ions
leave the discharge chamber, electrons are collected on the screen grid surface.
Grids: The electrostatic apertures by which the ions from the discharge are extracted
Grids are electrodes separated from each other by a few millimeters. Each grid has several apertures that
are aligned and allow for the extraction of ions. The grid closest to the discharge chamber is referred to as
the screen (or S) grid. Moving downstream, the next grid is referred to the accelerator (or A) grid. On
some sources, a third grid is used which is the furthest downstream from the discharge chamber and it is
referred to as the decelerator (or D) grid.

8
The grid assembly extracts ions from the discharge chamber by applying specific potentials (or
voltages) to each grid. A potential (or voltage) diagram of the ion acceleration process is presented
in Figure 2.2. First, the S grid is biased positive (beam voltage) with respect to ground and
consequently the plasma in the discharge chamber is also biased positive with respect to ground.
Next, the A grid is biased negative (accel voltage) with respect to ground and establishes an electric
field along the source centerline. Positive ions in the discharge chamber that drift close to this
electric field are accelerated.
Even if the D grid is not used, the potential downstream from the source is ultimately approximately
zero. Depicted in Figure 2.2 is the electric potential for a 3-grid assembly. The D grid potential is
typically held at ground potential (or 0 V). The accelerated ions then decelerate after passing the A
grid and exit the aperture with a net, ion energy of approximately beam voltage. As depicted in
Figure 2.2, electrons either located in the discharge chamber or downstream from the source are
separated due to the established electric field.
Ions extracted through the grid apertures comprise individual beamlets and a typical grid assembly
will have numerous apertures. As a result, individual beamlets combine to form a more, broad ion
beam.
Figure 2.2: Schematic of the ion acceleration process

9
Neutralizer: An electron source downstream from the ion source
For DC sources, the neutralizer can be a hot filament, hollow cathode, or plasma bridge type. A
plasma bridge neutralizer (PBN) is where a hot filament is placed in a smaller discharge chamber
through which an inert process gas is supplied. For RF sources, the neutralizer can be either a PBN
or RF type. The RF neutralizer (RFN) consists of a small discharge chamber with an RF coil. The
RFN utilizes a collector and keeper to emit electrons.
The purpose of the neutralizer is to emit electrons into the environment downstream from the ion
beam source. The emitted electrons provide a charge balance for the ions leaving the source.
Typically, more electrons are emitted from the neutralizer than ions from the source. This is done
to minimize and/or eliminate the space or surface charging that may occur. In most situations,
electrons from the neutralizer do not directly combine with the ions in the beam to form high
energy neutrals.

10
Section 2.1 Source Parameter Definitions
As electrical devices, ion beam sources require power supplies. Presented in Figures 2.3 and 2.4 are
the electrical schematics for typical DC and RF sources, respectively.
Figure 2.3: The electrical schematic for a filament DC source
In Figure 2.3, the electrical connections for a filament cathode and filament neutralizer DC source
are presented. The cathode is heated using an AC power supply. Electrons leaving the filament are
collected at the anode with the discharge supply, a DC bias supply. The beam supply, also a DC bias
supply, is also connected to the anode and biases the discharge plasma positive with respect to
ground. Not illustrated, but commonly used is a resistor placed between the body and anode. The
body resistor establishes the proper bias between the anode and body and thereby directs electrons
to be collected on the anode surface. The accelerator supply, a DC type supply, biases the accel grid
negative with respect to ground. Finally, the neutralizer filament is heated using an AC power
supply.
In Figure 2.4, the electrical connections for a RF source with RF neutralizer are presented. The RF
coil for the discharge chamber is energized by the RF supply and is tuned by using a matching
network.

11
The beam supply, a DC bias supply, is connected to the screen (S) grid in order to bias the discharge
plasma positive with respect to ground. The accelerator supply, a DC type supply, biases the accel
grid negative with respect to ground. Finally, the RF neutralizer utilizes an RF supply and matching
network for its own discharge and additional DC supplies to emit electrons.
Figure 2.4: Electrical schematic for a RF source
Additional power supply details and source parameters are presented in Tables 2.1 and 2.2. Ion
beam source parameters used by both DC and RF sources are presented in Table 2.1. Specific
parameters that pertain to DC filament, DC hollow cathode, and RF sources are outlined in
Table 2.2. Actual values for these source parameters will be specific to source type, size, grids, and
process. Typical values will be given where appropriate.

12
Table 2.1: Ion beam parameters for all sources
PARAMETER
DEFINITION
UNIT
All Sources
Source Gas Flow
Process gas delivered to the discharge chamber.
sccm
Beam Voltage
Positive voltage applied to the discharge plasma.†
V
Beam Current
The total ion current extracted, or leaving the source.
mA
Accel Voltage
Negative voltage applied to the accelerator (A) grid.
V
Accel Current
Charge-exchange current collected by accelerator (A) grid.
mA
A/B Ratio
Ratio of accel to beam currents. Indicates quality of grid
focusing. Typical A/B is < 10%.
%
Neutralizer Emission Current
The electron current emitted by the neutralizer.
mA
E/B Ratio
Ratio of neutralizer emission to beam currents. Typical E/B
is >100% to minimize space charging, surface charging and
arcing.
%
† For DC sources, beam voltage is applied to the anode. For RF sources, beam voltage is applied to the screen
(S) grid.
Table 2.2: Ion beam parameters for specific types of sources
PARAMETER
DEFINITION
UNIT
DC Filament Cathode (FC) / Filament Neutralizer (FN)
Cathode Filament Current
The electrical current applied to the filament cathode. This
current heats the filament so that electrons are emitted
from its surface.
A
Discharge Voltage
The voltage established between the filament cathode and
anode. This determines the electron energy for ionizing
collisions in the discharge chamber.
V
Discharge Current
The electrical current established in the discharge chamber
between the filament cathode and the anode. This current
controls the ion production rate and to first order, the
beam current.
A
Neutralizer Filament Current
The electrical current applied to the filament neutralizer.
This current heats the filament so that electrons are
emitted from its surface.
A
DC Hollow Cathode (HC) / Hollow Cathode Neutralizer (HCN)
Cathode Heater Current
The electrical current applied to the HC heater.
A
Cathode Keeper Voltage
The voltage established between the HC’s body and
keeper.
V
Cathode Keeper Current
The electrical current between the HC’s body and keeper.
mA
Discharge Voltage
The voltage established between the HC body and anode.
This determines the electron energy for ionizing collisions
in the discharge chamber.
V
Discharge Current
The electrical current established in the discharge chamber
between the HC body and the anode. This current
controls the ion production rate and to first order, the
beam current.
A
Neutralizer Heater Current
The electrical current applied to the HC heater.
A
Neutralizer Keeper Voltage
The voltage established between the HC’s body and
keeper.
V
Neutralizer Keeper Current
The electrical current between the HC’s body and keeper.
mA

13
Table 2.2: Ion beam parameters for specific types of sources (continued)
PARAMETER
DEFINITION
UNIT
RF with RF Neutralizer (RFN)
RF Forward Power
The RF power applied to the matching network. This
power controls the ion production rate and therefore, the
beam current.
W
RF Reflected Power
The RF power reflected from the matching network.
Typically, the reflected power is <1% of the forward power.
W
RFN Forward Power
The RF power applied to the matching network.
W
RFN Reflected Power
The RF power reflected from the matching network
W

14
Section 2.2: Ion Beam Properties
For ion beam deposition applications, it is necessary to know the energy of the ions leaving the
source and the dose that they strike a target downstream.
Ion Energy
The ejected ions from an ion beam source are considered mono-energetic and as depicted by
Figure 2.2, the total ion energy is approximately the beam voltage. In order to illustrate the
importance of this aspect, plotted in Figure 2.5 are two types of energy distributions. The ions in a
typical electrical discharge device will have a range of energies that form a distribution that is
thermalized; also referred to as Maxwellian. A Maxwellian energy distribution is plotted in
Figure 2.5 where the number of ions is plotted for various energies. For comparison purposes, the
energy distribution from an ion beam source is also plotted. Ions that leave the source have a
limited energy range, selected by the beam voltage, and are referred to as mono-energetic. The
significant attribute of the ion beam source is that energies of the ions can be adjusted by selecting
different beam voltages, where as, a Maxwellian discharge will have only limited adjustment in its
energy distribution. The beam voltage range is typically 100 to 1500 V.
Energy Distributions
0
0.2
0.4
0.6
0.8
1
0.01 0.1 1 10 100 1000
Energy (eV)
Energy Density
Maxwellian
Mono-Energetic
Adjustable
Limited Adjustment
Figure 2.5: Two types of energy distributions: Maxwellian and Mono-Energetic

15
Ion Dose
A measurement of the beam current is also an indication of the number of ions leaving the source.
In most applications, it is important to determine the number of ions striking a specific location
downstream, such as a target or substrate. This number is also referred to as the dose or flux
density. The actual dose downstream from the source is determined by the ion beam focusing
characteristics or ion optics.
Ion optics are determined by the beam current and voltage, accel voltage, and grid geometry (i.e. grid
thickness, spacing, and shape). In general terms, the ion beam diverges, or spreads out, as it leaves
the source. Custom grids can be fabricated to control this divergence and focus the ion beam. Ion
optics is a rather detailed subject, and therefore, only brief, general rules of thumb are presented
below for a typical grid set.
1) The divergence increases (the beam spreads out) when the accel voltage is increased.
2) The divergence can decrease at higher beam voltages.
Due to the complex nature of ion optics, the beam dose is best determined by measuring it using a
Faraday type probe. Recall, a Faraday probe is a small electrode biased negative, usually about 40 V
or so, to measure ion current and repel electrons. The probe is typically placed downstream from
the source and swept through the beam to measure ion current at locations of interest. The ion
current to the probe is divided by the area of the probe to determine the dose of the ion beam in
mA/cm2.

16
Section 2.3: References
[1] Wilbur, P.J., V.K. Rawlin and J.R. Beattie, "Ion Thruster Development Trends and Status in
the United States," J. Prop. and Power, V. 14, No. 5, Sept.-Oct. 1998, pp. 708-715.
[2] Rayman, M. D., P.V. Varghese, “The Deep Space 1 Extended Mission,” Acta Astronautica, V. 48,
No 5-12, 2001, pp. 693-705
[3] Kaufman, H.R., R.S. Robinson, “Broad-Beam Ion Sources,” Handbook of Plasma Processing
Technology, pp. 183-193, Noyes Pub., New Jersey, 1990.
[4] Wilbur, P. and B. Buchholtz “Surface Engineering using Ion Thruster Technology,” AIAA Paper 94-
3235, Joint Propulsion Conference, June 1994, Indianapolis, IN.
[5] McNally, J. “Ion Assisted Deposition,” Handbook of Plasma Processing Technology, pp. 466-
482, Noyes Pub., New Jersey, 1990.
[6] Zheng, A. “Optical Interference Filters: The Key in High Capacity Optical Systems,” Fiberoptic
Product News, N. 10, pp. 18 –24, 1999
[7] Izawa, T., et. al., “Ultra-low-loss multilayer reflectors and their applications.”, Japanese Journal of
Applied Physics, Vol. 62, No. 9, pp. 911-914, 1993.
[8] Chen, F. F. Introduction to Plasma Physics and Controlled Fusion, V. 1, pp. 1-51, Plenum
Press, New York, 1984.
[9] Lieberman, M. A., A. J. Lichtenberg Principles of Plasma Discharges and Material
Processing, pp. 1-124, John Wiley and Sons, New York, 1994.
[10] Cecchi, J. L. “Introduction to Plasma Concepts and Discharge Configurations,” Handbook of Plasma
Processing Technology, pp. 14-69, Noyes Pub., New Jersey, 1990.
[11] Monheiser J M, Wilbur P J, “An Experimental Study of Impingement-Ion-Production Mechanisms”
28th Joint Propulsion Conference, AIAA Paper 92-3826, 1992.
Chapter

17
Set up and Installation Procedures
Installing and operating the IBEAM FC / FN power supplies requires good safety practice. The
power supply must be turned OFF before performing ANY electrical connections. All warnings
and cautions must be observed. The power supply should NEVER be operated with ANY of its
output connections MISSING or IMPROPERLY attached. READ ALL INSTRUCTIONS before
connecting power.
Chapter
3
CAUTION
Danger of High Voltage and Personal Injury
WARNING
ALL POWER OUTPUTS CAN BE LETHAL
WARNING
ELECTRICAL SHOCK HAZARD
WARNING
This power supply produces high voltage outputs. Do not operate
unit with missing or improper connections. The unit’s interlock
needs to be incorporated into the facility/system interlock string.
There are no serviceable parts inside the unit. Do not remove unit
cover.