Jandel RM3000 User manual

RM3000 Test Unit Instrucons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 1
RM3000 Test Unit Soware Instrucons . . . . . . . . . . . . . . . . . . . . . Page 11
RM3000 USB/RS232 Command Reference Sheet . . . . . . . . . . . . . . . Page 17
RM3000 Status Output Word . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 18
RM3000 Calibraon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 19
RM3000 Test DIN Plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 22

RM3000 Test Unit Instructions
The RM3000 is a combined constant current source and digital voltmeter. It
has been designed for use in making resistivity measurements in
combination with four point probe equipment. The unit supplies a constant
current and can display the resultant voltage, sheet resistance or volume
resistivity depending which function has been chosen. For calculation of
volume resistivity it is possible to input wafer thickness or probe spacing as
required.
Unpacking
When you unpack the RM3000 you should find:
1) A Jandel RM3000 Test Unit
2) A power lead
3) A 100 ohm test resistor
4) A green case key which can be used to open the RM3000 cabinet (not
recommended)
5) A copy of the RM3000 software for computer control and exporting
of results
6) A USB lead
Getting to know the RM3000
On the RM3000 you will find the display area:
This is where the current being used is displayed, the direction of the current
and the output in mV, ohms/square and ohm.cm.

There are also a number of buttons, the names used throughout this manual
are listed here:
To the left on the front of the unit you will find:
Numeric Keypad Current level buttons
Ohm button
To the right of these there are four more buttons:
Forward button Standby / Auto
button
Reverse button Zero button
There are four ‘preset buttons’ marked A-D.

Four buttons remain as follows:
High button Low button
Store button Mode / Test Button
Operation of the RM3000
Selecting a current
The keypad is used to input the desired current. It is used in combination
with the current level buttons.
The current level buttons are (nanoamps), (microamps) and
(milliamps). Values between 10nA and 99.999mA can be entered, and
the accuracy of the current delivered does not depend on the number of
decimal places inputted, i.e. 10nA (pressing 1, 0, nA) is equivalent in
accuracy to 10.00nA (pressing 1, 0, ., 0, 0, nA)
Storing Currents using the Preset Buttons
Commonly used currents can be stored in positions A to D. When the
required current has been dialled in, pressing and holding one of the buttons
will store the current in that location. Successful storing is demonstrated by
the unit beeping. Retrieving the currents is done by simply pressing the
relevant letter.
Displaying ohms/square , ohm.cm or mV values
Pressing the ohms button toggles the display between giving measurement
results in mV and one of ohms/square, ohm.cm (wafers) or ohm.cm
(volume). The default setting toggles between mV and ohms/square.
Pressing and holding the ohms button until a beep is heard will change this
to toggle between mV and ohm.cm (volume resistivity). Pressing and
holding again until a beep is heard will change it to toggle between mV and
ohm.cm (for wafers). To get the correct results for wafers or volume

resistivity information on probe spacing or wafer thickness may be required
from the user which is discussed later in the manual. If the unit is switched
off then next time it is switched on it will be on the default setting of
toggling between mV and ohms/square.
When using FWD and REV the voltage is indicated as either positive or
negative on the screen. For ohms/square and ohm.cm values the display will
show either ‘F’ for forward current or ‘R’ for reverse current.
If the setting is ohm.cm for wafers a ‘W’ will also appear when displaying
ohm.cm values to indicate that this is the measurement mode
Starting or stopping current flow through the sample
Pressing the forward button will pass the selected current through the probe
head in a forward direction, and should yield a positive voltage reading.
Pressing the standby button when current is flowing in the forward or
reverse direction will put the unit in standby so that no current is flowing.
Pressing the standby button while the unit is already in standby will begin
the autorange feature which is discussed later in this manual.
Pressing the reverse button will pass the selected current through the probe
head in a reverse direction, and should yield a negative voltage reading of
equal or similar magnitude to the forward reading
High Resolution
The High button puts the unit in high resolution mode and is the most
desirable setting for high accuracy measurements. In high resolution
voltages from 0mV to 150mV can be measured.
Low Resolution
The Low button puts the unit in low resolution mode. Low resolution can be
used where less accuracy and higher speed are required, or where highly
insulating samples are being measured which yield a voltage higher than
150mV, but below 1.2V which is the unit’s measurement limit.
Storing Readings
Pressing the store button stores the displayed voltage value to on board non
volatile memory. If the display is showing an ohms/square or ohm.cm
reading the equivalent voltage reading is stored. The measurements stored

on the unit can be deleted by pressing and holding the Store button until the
display shows that the readings are being deleted. Stored measurements can
be retrieved from the unit with the RM3000 software. Readings are time-
stamped using an on-board clock.
System Test
The RM3000 is supplied with a 100 ohm test resistor. When this resistor is
plugged into the rear of the unit and the Mode/Test button is pressed the
RM3000 will perform a self test against an internal reference (this process
takes several minutes).
Mode
The mode button allows user adjustable settings to be changed. Pressing and
holding the Mode/Test button enters the adjustment menu where the
following items can be changed:
1. V Correction. This multiplies the measured voltage by the correction
factor entered here, for instance if readings need to be corrected for sample
size. The correction can be entered by using the keypad and the stored by
pressing ‘Store’. Displayed voltages will be shown having been multiplied
by the correction factor, and if this is the case an asterisk (*) will be shown
on the display to indicate that the voltage has been adjusted. The correction
can be removed by setting the correction to 1.00, by setting the unit to its
default settings or by switching the unit off and on.
2. Wafer thickness. Here the thickness of wafers being measured can be
entered (in cm). This enables the unit to display the value of such items in
ohm.cm. The default setting is 650 microns (0.065cm). This setting is held
in non-volatile memory and so will not change when the unit is switched off.
It can be returned to the default value manually or by resetting the RM3000
to its default settings.
3. Probe spacing. The probe spacing (in cm) can be entered here. This
enables the unit to display the volume resistivity of bulk samples in ohm.cm.
The default setting is 0.1000 (1mm spacing). This setting is held in non-
volatile memory and so will not change when the unit is switched off. It can
be returned to the default value manually or by resetting the RM3000 to its
default settings.

4. Time. Here the correct time can be entered for time stamping readings
taken by the RM3000. The time is set by entering the correct time using the
keypad by entering hours, minutes and seconds separated by a period in the
format HH.MM.SS and then pressing ‘store’.
5. Date. Here the correct date can be entered for date stamping readings
taken by the RM3000. The date is set by entering the correct date using the
keypad by entering the day, month and year separated by a period in the
format DD.MM.YYYY (if the unit is in UK format) or MM.DD.YYYY (if
the unit is in US format).
6. Date format. Here the user can press ‘1’ for UK date format
(DD.MM.YYYY) or ‘2’ for US date format (MM.DD.YYYY).
7. Set defaults. This it to reset the unit to its default modes. To reset it is
necessary to type in the code ‘222’ and press store – this is to prevent
someone accidentally resetting the unit.
Default modes are as follows:
V Correction: 1.00 (resets to this when unit is switched off)
Wafer thickness: 0.0650cm (non-volatile)
Probe spacing: 0.100cm (non-volatile)
Set time: current set time (non-volatile)
Set date: current set date (non-volatile)
Date format: UK (non-volatile)
Getting Started – First use of the RM3000
When using small currents or measuring small voltages we recommend a 15
minutes warm up period for the unit. For currents above 1uA a 5 minute
period is recommended. For the largest currents / voltages no warm up
period is required.
Switch the unit on. The RM3000 will self calibrate and then zero before
putting itself in Standby. The unit is now ready to use with the default
resolution ‘High’.

Plug in the 100 ohm test resistor so that the unit will believe it is measuring
a sample.
Set a current of 1mA (press ‘1’ and ‘mA’).
Press ‘FWD’. The unit is now passing a current through the resistor and
measuring the voltage. As V=IR you can expect a reading of 100mV. The
unit’s accuracy is quoted at 0.3% so the reading should be between 99.70mV
and 100.30mV. In practice, particularly above 1mV and when warmed up
the accuracy is better than 0.3% so it would not be unusual to find that you
are within 0.1% of the expected value.
Press ‘REV’. The RM3000 is now passing current in the reverse direction.
Again you should receive a reading of 100mV, but this time with a minus
figure.
The voltages made may be slightly offset. In this case press the Zero button
to remove the offset. The zero button is most effective when pressed while a
current is being passed.
Press the ‘Ω / □’button. For thin samples the most commonly used
measurement is sheet resistance. This is measured in ohms per square. As
the size of the square is not relevant to the measurement there are no units
such as ‘square centimetre’ or ‘square metre’. The formula for sheet
resistance is quite complicated but can be resolved to 4.5324 x V/I. When
using a 100 ohm resistor you can expect the reading to be approximately
453.24 ohms/square.
Press the ‘Ω / □’button again and the unit will once again show the reading
in mV. Note that the ohms/square value is absolute and therefore does not
have a positive or negative sign, but ‘F’ or ‘R’ will be shown on the display
to indicate in which direction the current is flowing.
The range of measurement in high resolution is 0-150mV. In Low resolution
it is 0-1250mV. Where practicable the high resolution should be used and a
mV reading of 10-100mV is ideal.
With the unit back in Standby remove the resistor. Attempt to make a
reading by pressing the ‘FWD’ key. This will cause an error and the
message “Contact Limit” will be displayed. By removing the resistor the
RM3000 can’t drive the current – you can therefore equate this to a four

point probe being on a sample but the RM3000 having a problem driving the
current. This could be because the sample is too insulating, because the
current needles are not in proper contact with the sample, or simply that a
lead is disconnected! Using a lower current will sometimes prevent a
‘Contact Limit’ error – this could be a situation where the sample has
become damaged due to excessive current, or where the contact resistance of
the material is high.
Autorange
Queries for poor results are often raised where the cause is simply that an
inappropriate current has been selected. The Autorange facility is not
designed for use before every measurement, but can be used to select an
appropriate current range for the samples being measured.
When making measurements and the RM3000 is in standby, pressing the
Standby button will initiate the Autorange feature. It will begin at 10nA and
increase the current by a factor of 10 until a suitable level of voltage
measurement is made. At this time it will stop and display the voltage. It is
not necessary to use only the current given for the measurements, but it
indicates the level around which optimum results can be achieved.
Example:
Plug in the 100 ohm test resistor and while the unit is in standby press the
Standby / Auto button. The unit will begin to autorange and should stop at
100uA current (yielding 10mV reading).
Where a sample has very high or very low resistivity you may observe the
following:
Low resistivity – the current will autorange up to its maximum current and
stop (99.99mA). This does not mean that the reading obtained is invalid,
simply that the measured voltage is below what we consider to be ideal.
Where the maximum current is required and the reading is below 10mV it is
more likely that the unit will need to be zeroed (while the probe is in contact
with the measured material and the current is flowing) in order to get good
forward and reverse readings.
High Resistivity – samples with very high resistivity can sometimes take
some time to reach the optimum voltage level. If a contact limit is obtained
when the unit has reached only the 10nA or 100nA level try setting 10nA

and observing what happens. It may be that the sample can still be measured
but it is necessary to note that:
1) The voltage may take a period of a few seconds, up to a couple of
minutes, to reach the voltage to be measured. In this case the ‘peak’
voltage should be noted.
2) The unit may need to be set to Low sensitivity. This is the case if the
RM3000 displays ‘Out of Range’ rather than ‘Contact Limit’. If the
measurement still cannot be made but ‘Out of Range’ is displayed it is
possible to measure the voltage using an external voltmeter plugged
into the rear of the RM3000 (this is where the voltage exceeds 1.2V).
Error Messages
During attempting a reading several error messages are possible instead of a
reading.
“Out of Range” indicates that the reading exceeds the maximum input of the
in-built DVM. Reduce the current or the sensitivity of the internal DVM, or
use an external DVM.
“Contact Limit” indicates that the automatic compliance voltage has been
reached due to contact resistance or too much current, try reducing the
current
“Illegal Current” indicates that the set current is outside the normal 10nA to
99.999mA range. Set a new current.
“Calibration Error” indicates an error in the factory calibration
Calibration / Self Calibration
The overall calibration of the current source is carried by potentiometer
adjustment. The internal DVM has no calibration potentiometers; its
calibration is carried out in the factory. This can be recalibrated if required.
If the calibration factor is outside certain limits or has become corrupted
‘Calibration Error’ is displayed.
A separate internal DVM calibration occurs at power up. It recalibrates
against an internal reference at power up and when changing from Low to
High sensitivity, or vice versa. Zeroing also occurs at this time.

Compliance Voltage
The compliance voltage is automatic, and is used to limit the power
dissipated in the sample under test. For currents under 1mA the voltage
applied is the maximum 40mV. For currents of 1mA and above the voltage
applied to the source is limited to an absolute maximum of 25V. Above
10mA the voltage is limited so as no more than 0.5W could possibly be
dissipated in the sample, so at 50mA the compliance voltage is limited to
10V, and at 99.999mA it is limited to 5V. Extra caution is required on the
use of currents over 10mA to avoid damaging the samples.
Useful Equations
Sheet resistance = 4.5324 × V/I (units ohms/square)
Bulk Resistivity for a wafer = sheet resistance × wafer thickness in cm (units
ohm.cm)
Bulk Resistivity = 2 × π× s × V/I where s is the probe spacing in cm (units
ohm.cm
Siemens are the SI unit of electric conductance and represent the reciprocal
of electrical resistance.
Correction Factors
Probing close to the edge of a sample or on unusual / intermediate shapes
and sizes of sample can mean that correction factors are required.
A broad range of correction factors have been determined by Haldor Topsoe.
At http://www.jandel.co.uk/topsoe.html you can find all of the pages from
the 1966 (revised 1968) Haldor Topsoe book, "Geometric Factors in Four
Point Resistivity Measurement", with each page available as an individual
PDF file.
Software
The next section of the manual deals with the use of the software supplied
with the RM3000.

RM3000 Test Unit Software Instructions
When the software is opened it gives a graphical representation of the unit
itself. Anything displayed on the unit’s LCD screen is displayed in the green
area of the software.
FIGURE 1
Note that the LED’s are also represented. In figure 1 the unit is in ‘standby’
and so the LED next to the standby button is illuminated.
The RM3000 can be controlled via the software by clicking on the display
buttons as if pressing the unit’s buttons. Please refer to the RM3000
instruction manual for how to use the unit.

Stored Readings
Stored readings are shown in the bottom left corner of the software display
with the most recently taken reading at the top. The number of readings
stored is shown by the number to the left of the top reading shown. When
more than four readings are stored it is possible to scroll through the
readings using the scroll buttons to the right of the ‘stored readings’ area.
Deleting Readings
If a reading has been taken which the user no longer requires it is possible to
delete it from the list. Scroll through the readings so that the reading to be
deleted is on display and click on the reading to highlight it. If you now
‘right click’ the reading will be erased.
It is not possible to recover deleted readings.
Pop-up menu.
Right clicking on the software screen will give a pop-up menu as shown in
Figure 2.
FIGURE 2
There are a number of options and these can be used as follows:
Connect – if the computer and RM3000 have ceased communicating after a
period of inactivity then clicking this will reconnect them
Save Readings – if you want to save the readings that are showing in the
‘Stored Readings’ area of the software, clicking this will give you the save
options (see ‘Exporting Measurements’ below).

Clear List – this will clear the list of readings (if any) which are stored in
the bottom left corner of the software window
Erase Memory – if the RM3000 has readings stored in its memory then this
will erase those readings. Erased readings cannot be recovered
Download – this will download any readings which have been stored to the
internal memory of the RM3000. While downloading readings you will see
an information window showing progress (Figure 3). This only takes a few
seconds and it is necessary to wait until the process is complete, at which
time there is an option to clear the stored results from the RM3000 memory.
FIGURE 3
About – this gives software version and copywrite information
RM3000 State – this gives the pop-up shown in Figure 4
FIGURE 4
This represents the state of the RM3000 in its basic form and can be used for
diagnostics in case of suspected errors.

Settings – this enters the menu for selecting auto-detect or manual port
select for the RM3000, and to give the location of the default spreadsheet
program
Enter Menu (MODE button) – this enters the menu as if pressing and
holding the ‘MODE’ button on the RM3000 to adjust probe spacing, time,
date etc.
Quit – this will safely quit the RM3000 software program
Exporting Measurements
By right clicking and selecting ‘Save Readings’ you can export readings to a
spreadsheet in one of several formats.
FIGURE 5
In the ‘Save Readings’ window, clicking on the down arrow by ‘Select
Export Type’ will give you 4 saving options (Figure 5). These can be used as
follows:
Current / Voltage only – outputs the current setting and voltage
measurement only for each stored reading
Sheet resistance – this outputs the current setting and voltage measurement,
along with the calculated sheet resistance

(The next two options require user input for the calculation)
FIGURE 6
Bulk Resistivity for Wafers – this can be used where the bulk resistivity of
a thin material is required. It outputs the current setting and voltage
measurement, along with the calculated Bulk Resistivity. For this type of
measurement it is necessary to input the sample thickness in centimetres (on
the left in Figure 6) I.e. for a typical wafer thickness of 600 microns, the
thickness is 0.06cm.
Bulk Resistivity – this can be used where the bulk resistivity of a large
piece of material is required (typically samples > 5x probe spacing). It
outputs the current setting and voltage measurement, along with the
calculated Bulk Resistivity. For this type of measurement it is necessary to
input the probe spacing in centimetres (on the right in Figure 6) I.e. for a
typical probes spacing of 1.00mm, the spacing is 0.1cm.
When you have chosen your output and, if necessary, inputted the required
information, click ‘browse’ to select an output file name and location on
your computer. The program will output the results in a CSV format (comma
separated variable) which can be displayed on the vast majority of spread
sheet programs.
FIGURE 7

Firgure 7 shows a typical spreadsheet output, in this instance showing the
calculated sheet resistance. Note that the units and the values have been
placed in separate columns so that if required it is possible to write
algorithms to manipulate the numerical values.
Keyboard operation
With the software running, or through interface software such as
HyperTerminal, it is possible to control the RM3000 using the computer
keyboard. The remote control commands simply mimic the operation of the
keypad.
The keyboard controls are:
“1” to “9” and “.” to set the current. Terminate in “m”, “u”, or “n”
“m” for mA
“u” for uA
“n” for nA
“e” will erase the current setting. If entering a current sending.
“f” sets the forward current
“r” sets the reverse current
“s” puts the RM3000 in standy mode
“z” zeros the reading
“h” sets high resistivity mode (either 2 or more decimal places max +/-
150mV)
“l” low sensitivity (1 decimal place max +/- 1250mv)
“a” first preset current
“b” second present current
“c” third preset current
“d” fourth present current
“q” changes display from ohms/sq to mV

RM3000 USB/RS232 COMMAND REFERENCE SHEET
ASCII HEX Description Key(s)
D 44 Download – Must be followed by a memory entry number 0-49 as ASCII N/A
a-d 61-64 Sele ts pre-set A-D A,B,C,D
0-9 30-39 Represents a digit for urrent entry 0-9
r 72 Reverse Mode REV
f 66 Forward Mode FWD
/ 2F For e the remote probe to enter position based on the status of STBY N/A
s 73 Standby Mode STBY
A 41 Begin an Auto range AUTO
+ 2B Enter the Settings Menu MODE
~ 7E Toggle Impedan e mode – R/sq, R/ m, R/ m/W R. m
t 74 Enter Self Test TEST
q 71 Toggle Voltage or Impedan e R/sq
z 7A Zero Offset ZERO
v 76 Version Output N/A
M 4D Store reading to next available memory position STORE
! 21 Erase ALL stored readings from memory STORE
= 3D Return free memory N/A
o 6F Output data in text format: Current, Voltage, R/Sq N/A
l 6C Enter Low sensitivity mode LOW
h 68 Enter High sensitivity mode HI
m 6D Represents milliamps when entering a urrent mA
n 6E Represents nanoamps when entering a urrent nA
u 75 Represents mi roamps when entering a urrent uA
e 65 Erase urrent entry or reset setting DEL
. 2E De imal Point used for urrent entry .
g 67 Output LCD Capture with 32 status bits as a HexWord N/A
Below are the command for factory and calibration u e only.
ASCII HEX Description Key(s)
* 2A Enter Calibration Mode – On e sent, alibration features are unlo ked N/A
@ 40 Prompts for a value to slightly adjust urrent output for
10nA/100nA/10mA ranges only
N/A
x 78 Calibrates DVM with urrent 1 volt reading N/A

1
RM3000 Status Output Word
These 32 bits of status information are outputted when using the g command.
It is in Hexadecimal Word Format
Byte Bit Description
17 FWD Mode, Also represents the FWD LED
6 REV Mode, Also represents the REV LED
5 Not used
State of the ZERO relay
3 Not used
2 Not used
1 State of the BACKLIGHT
0 State of the BUZZER
27 State of the FWD/REV Relay
6 Current Range 10nA+
5 Current Range 100nA+
Current Range 1uA+
3 Current Range 10uA+
2 Current Range 100uA+
1 Current Range 1mA+
0 Current Range 10mA+
37 A valid reading (e.g. No Errors)
6 Sensitivity Mode Set=High mode
5 Impedance mode Clear=Voltage mode
Auto Ranging
3 Memory Full
2 Downloading
1 In the Maths / Setting Menu
0 Mid-Current Entry
47 Zeroing
6 Calibrating the DVM
5 Illegal Current
Contact Error
3 Out of Range
2 Calibration Error
1 Passed Test Clear=Failed
0 Failed Test Set=Passed

JandelRM3000Calibration

Introduction

TheJandelRM3000combinesaconstantcurrentsourcewithaDVM.Thesystemis
micro‐processorcontrolledandcanbeoperatedviathefrontkeypadandLCDorvia
theserialorUSBport.















RequiredEquipment

oBenchtopDVMwith5decimalplacesresolution
o1M,1Kand100RTestResistorsinplugs0.1%accuracy(refertoseparate
document:JL21070602.pdffortestplugdetails)
oAPCwithUSB,RM3000DriversandaSerialTerminalEmulator(suchas
HyperTerminal)



Procedure

1. ConnecttheUSBandpowerontheRM3000.ConnecttheSerialTerminal
Emulatorwithsetting9600,n,8,1.Checkcommunicationsbysendinga‘g’–
theunitshouldrespondwithanLCDdump.Nowsendtheunita‘*’toputit
intofactorymode.


