Keithley 595 User manual

Model 595 Quasistatic CV Meter
Quick Reference Guide
A GREATER MEASURE OF CONFIDENCE
Specifications are subject to change without notice.
All Keithley trademarks and trade names are the property of
Keithley Instruments, Inc. All other trademarks and trade names
are the property of their respective companies.
Keithley Instruments, Inc.
28775 Aurora Road • Cleveland, Ohio 44139
440-248-0400 • Fax: [phone]
1-888-KEITHLEY (534-8453) www.keithley.com
© Copyright 2000 Keithley Instruments, Inc.
Printed in the U.S.A. 04/2001
Model 595 Quasistatic CV Meter
Quick Reference Guide
A GREATER MEASURE OF CONFIDENCE
Specifications are subject to change without notice.
All Keithley trademarks and trade names are the property of
Keithley Instruments, Inc. All other trademarks and trade names
are the property of their respective companies.
Keithley Instruments, Inc.
28775 Aurora Road • Cleveland, Ohio 44139
440-248-0400 • Fax: [phone]
1-888-KEITHLEY (534-8453) www.keithley.com
© Copyright 2000 Keithley Instruments, Inc.
Printed in the U.S.A. 04/2001
595-903-01A 2UP Covers 2/19/03 2:02 PM Page 1

INTRODUCTION
Thisreferenceand programmingguide containscondensed
specifications, descriptionsof the variousfeaturesandin-
formationfor usingthe Model 595. Also, IEEE-488program-
minginformationandseveralexampleprogramswritten for
commonly used controllers are also included to get the
Model 595 "up and running" on the bus.
The Model 595Quasistatic CV Metermeasurescapacitance
usingauniquefeedbackchargemethod.This methodcor-
rectscapacitancereadings for backgroundleakagecurrent.
A built-inIEEE-488interface, plotterdriver andlabeledgrid
programenablethe Model 595to plot IV or quasistatic CV
curves for a variety of semiconductor materials and
components.
01986, Keithley Instruments, Inc.
Instrument Division
Cleveland, Ohio, U.S.A.
Document Number: 595-903-01 Rev. A
1

TABLE OF CONTENTS
CONDENSED SPECIFICATIONS .................. 3
MODEL 595 FEATURES ..................... 7-20
FRONT PANEL PROGRAMS ................. 21-26
MEASUREMENT CONNECTIONS ............. 29-34
IEEE PROGRAMMING ...................... 35-49
PROGRAMS ................................ 50
IBM
PC or XT .......................... 51
Applell
............................... 53
HP85 ................................ 55
HP9816
.............................. 57
HP9825A ............................. 59
DEC El 11 ............................ 61
PETICBM 2001 ......................... 63
2

CONDENSED SPECIFICATIONS
CAPACITANCE
Maximum Allowable
Wt at Half Range C
Reso- (1 bar) 18-28OC Delay Time=O.Oirsec
Accuracy'
Range lution +(%rdg+counts) Step
V=O.lV
200pF lOfF 1.0 + 10 9O.OOOpA
2nF lOOfF
0.8 + 2 0.900nA
20nF OF 0.6 + 2 9.000nA
*Exclusive of noise, for Step V 2 0.05V and
Delay Time 5 one second.
CURRENT
Temperature
Accuracy' Coefficient
Reso- (1 Bar) 18-28OC 0-18OC
& 28-4OoC
Range lution
? (%rdg+counts) f (%rdg + counts)l°C
20pA 1fA
200pA lOfA
2nA 1OOfA
20nA 1pA
200nA lOpA
2pA 100pA
20pA 1nA
200pA lOnA
1.5 + 14
1.5 + 2
0.25 + 6
0.25 + 1
0.1 + 4
0.1 + 1
0.1 + 4
0.1 + 1
0.15 + 3
0.15 + 0.3
0.015 + 3
0.015 + 0.3
0.01 + 3
0.01 + 0.3
0.01 + 3
0.01 + 0.3
*When properly zeroed.
3

VOLTAGE SOURCE
OUTPUT: -2O.OOV to 20.00V in 0.01V increments.
ACCURACY (1 YEAR, 18-28OC): 2(0.2% + 1OmV).
MAXIMUM OUTPUT CURRENT k2mA; active currentlimit
at <4mA.
ANALOG OUTPUTS
C,l OUTPUT LEVEL: 1V represents 10,000 display counts
VOLTAGEOUTPUT LEVEL 1V represents 1OV on voltage
MAXIMUM OUTPUT VOLTAGE: k2V.
on X1 gain; 1000 display counts on X10 gain.
source output.
GENERAL
MAXIMUM INPUT: 30V peak, DC to 60Hz sine wave.
MAXIMUM COMMON MODE VOLTAGE 30Vmaximum, DC
to 60Hz sine wave.
ENVIRONMENT: Operating: Oo to 4OoC, relative humidity
70% non-condensing up to 35OC. Storage: -25O to
65OC.
WARM UP 2 hours to rated accuracy except input bias
current ( < 10fA after 2 hours, < 5fA after 8 hours, at
23OC)
POWER 105-125V or 210-250V (internalswitchselected).
50Hz to 60Hz. 15VA max. 90-11OV and 180-220V ver-
sion available upon request.
4

Thefollowingsafetyprecautionsshould be observedbefore
using
this product and any associatedinstrumentation Al-
though some instruments and accessoria would normally
be used with non-hazardous voltages, there are situations
where hazardousconditionsmay he. present.
This productisintendedfor use by qualifiedpersonnelwho
recognize shock hazards and are familiar with the safety
precautions
required to avoidpossibleinjury.Readandfol-
low
all installation,operation,andmaintenance information
carefullybefore using the product.Refer to the mauualfor
completeproductspecificatiom.
If the product is used in a manner not specified,the protec-
tionprovidedby the productmay
be impaired.
The
types of productusen are:
Responsiblebody is the individual or group responsiblefor
the
use and maintenance of equipment, for ensuring that the
equipment is operated with its specifcations and operating
limits, andforensuring that operators are adeqatelytrained.
Operators use the product for its intended function. They
must
be trained in electricalsafety procedures andproper use
of the instrument. They must be protected from electric
shock and contact with hazardouslive Circuits.
Maintenance personnel performroutine procedures on the
productto
keep it operating properly,forexample, setting the
line voltage or replacing collsumable materials. Maintenance
procedms are described in the manual.Theproceduresex-
plicitly
state if the operatormay perform them. othenvise,
they shouldbe performed onlyby service personnel.
Service personnel are trained to work on livecircuits, and
perform safe installations and repairs of products. Only
properlytrainedservicepersonnelmay performinstallation
and serviceprocedws.
Keithleyproducts
are designed for use with electrical sig-
nals that are rated Installation Category I and Installation
5/02

Category II, as described in the International Electrotechni-
cal Commission (EC) Standard IEC 60664. Mostmeasure-
ment, control,and data
YO signals are InstallationCategory
I and must not be directly connected to mains voltage or to
voltage
sources with high transient over-voltages. Installa-
tion Category II connections qubt protection for high
transientover-voltagesoften associated withlocal AC mains
connections.Assume all measuremenfcontrol,and data YO
COM~C~~OUS are for connection to Category I sources unless
otherwise marked or described inthe Manual.
Exercise extremecaution when a shock hazard is present.
Lethal voltage may be present on cable connectorjacks or
test fixtures. The American National Standards Institute
(ANSI) states that a shockhazard existswhen voltagelevels
greater than 30V RMS, 42.4V peak, or 6OVDC are present.
A good safety practice is to expect that hazardous voltage
is present in any unknown circuit before meamring.
Operators of this product must be protected from electric
shock a! all times. The responsible body must ensure that
operators are prevented access and/or insulated from every
connection point.
In some cases, connectionsmust be ex-
posed to potentialhuman contact.Product operators in these
circumstancesmust
be trained to protect themselves from
the
risk of electric shock. If the circuitis capable of operat-
ing at or above loo0 volts, no conductive part of the cir-
cuit maybe exposed.
Donot COMect switching cards directly to lmlialite4lpowercir-
cuits. They are intended to be used witb impedance limited
sources. NEVER connect switching cards directly to AC
mains. When connecting so- to switch cards, install
proteCrivedevices tolimitfaultCUlTent andvoltage to the card.
Before operating an instrument,make sure the linecord is
connected to a properlygroundedpowerreceptacle. Inspect
the connectingcables,test leads, and jumpers for possible
wear, cracks,
or breaks before each use.
When installing equipment where access to the main power
cord
is restricted, such as rack mounting,a separate main in-
put power disconnectdevicemust be provided,
in closeprox-
imity to the equipmentand within easyreachof the operator.

For maximum safety, donot touch the product, test cables,
or anyotherinstrumentswhilepower is appliedtothecircuit
under
test ALWAYS removepowerfromtheenfiretest sys-
tem and dischargeanycapacitorsbefore: connectingor dis-
connecting cables or jumpers, installing or removing
switching
cards, ormakinginternalchanges,such as install-
ing
or removing jumpers.
Do not touch any object that couldpruvideacurrent path to the
common side of the circuit under test or power line (earth)
ground. Always make measllrements with dry hands while
standing on a dry, insulated slnface capableof withstanding the
voltage bkng measured
Theinstrumentand accessoriesmust be usedin accordance
withits specificationsandoperatinginstructions
or the safe-
ty of the equipmentmay he impaired.
Do notexceedthe maximum signal levelsof theinstruments
and accessories, as definedin the specificationsand operat-
ing information, and as shown ontheinstrumentor test fix-
ture panels, or switchingcard.
When fuses
are used in a product, replace with same ty-pe
and rating for continuedprotectionagainst fire hazard.
Chassis connections must only be used as shield connec-
tions for measuring circuits, N(TT as safety earth ground
connections.
If you are using a test fixture, keepthelidclosedwhilepow-
er
is appliedtothedevice under test.Safeoperation requires
the use of a lidinterlock.
If @orb ispresent,connectittosafetyearthgromd
usingthe wire recommendedinthe user documentation.
The A symbolon an instrumentindicatesthat the user
shouldrefertotheoperatinginstructionslocatedin theman-
ual.
The A symhol on aninstrumentshows that it can source
or measure lo00 voltsormm,including the combinedeffect

of normal and common mode voltages. Use standad safety
pmtionstoavoid
personal contact with thesevoltages.
The
WARNING headingin a manual explains dangers that
mightresultin personalinjury
or death. Always read the as-
sociated information very carefullybefore performing the
indicatedprocedure.
The
CAUTION beadingin a manual explainshazardsthat
coulddamagethe instrument. Such damage may invalidate
the warranty.
Instrumentation and accessories shall not be connectedto
humans.
Before
performing any maintenance, disconnect the line
cord and all test cables.
To maintain protectionfromelectricshockand lire, replace-
ment components in mains circuits, including the power
transformer,
test leads, and input jacks, must be purchased
fromKeithleyInstruments.
Standard fuses, with applicable
nationalsafetyapprovals,may
be used if the rating and type
are the same. Other componentsthat are not safety related
may
be purchasedfrom other suppliers as long as they are
equivalent to the original component. (Note that selected
parts should
be purchased only through Keithley Instru-
ments to maintain accuracy and functionalityof the prod-
uct.) If you
are unsure about the applicability of a
replacementcomponent,call a Keithley Instrumentsoffice
for
information.
To clean an instnunent, use a dampcloth or mild, water based
cleaner. Clean theexteriorof the instrumentonly. Do not ap
ply cleanerdirectlytothe instrument
or allowliquidstoenter
or spill
on the instrument.products that consist of a circuit
board with no caseorchassis(e.g., data acquisition board for
installationintoa computer)shouldnever requhe cleaning if
handledaccording to instructions. If the board becomes con-
taminated and operation is affected,the board should be re-
turned tothe factoryforpropercleaning/servicing.

SAFETY PRECAUTIONS
1. Before operation, groundthe instrument through a prop-
erly earth-grounded power receptacle.
2. Before servicing, disconnect the instrument from the
power line and all other equipment. Consult the Model
595 Instruction Manual for service information.
3. Do nottouch anyterminals whilethe instrumentisturned
on or connected to any test equipment.
WARNING
The maximumcommonmode
input voltage(the
voltagebetweeninput
low andchassisground)
is
30V peak. Exceedingthis value may createa
shock hazard.
CAUTION
The maximumvoltage betweeninput highand
input lowis
30V peak. Exceedingthisvaluemay
causedamage
to the instrument. Current inputs
that exceed3mA maybeerroneouslydisplayed
as an on-scale reading.
5

DISPLAY MESSAGES
Message
OFF
dc
A1
l?=S
P.=O
P.=C
OL
triG
bErr
nErr
tErr
r.r.
r.0.
[*].[*I.
[*I.[*].
Description
Voltage source is OFF (0.OOV ?O.OlV)
and Model 595 is set to measure
capacitance.
Voltage source is set to DC waveform and
Model
595 is set to measure capacitance.
Software revision level; displayed as part
of diagnostics.
Troubleshooting diagnostics: Phases:
signal, zero and calibration reference.
Overload (overrange input applied);
-0L
for negative value.
Instrument is waiting for a trigger (bus,
external, or front panel SHIFT, then
?I.
Bus Error: Instrument programmed while
not in remote; or illegal command or com-
mand option sent.
Number Error: Calibration, voltage source,
waveform parameter, or program value
beyond allowable range.
Trigger Overrun Error: Instrument triggered
during a measurement conversion.
RAM Test Failure:
ON while RAM memory
is being tested. If message remains, the
test failed.
ROM Test Failure:
ON while ROM memory
is being tested. If message remains, the
test failed.
Flashing Decimal Points in Exponents:
Power up calibration constants are not
in
use (dueto nonvolatile memory error on
power up or calibration adjustment
without storage).
Decimal Points Turned On in Exponent:
Calibration program is in use.
6

SHIFT
r SHIFT
Severalof the front panel buttonshave a secondary func-
tion. Thesefunctionsare labeledinyellow, as isthe SHIFT
button. Secondaryfunctions are selectedbyfirst pressing
the SHIFT buttonand thenpressingthedesiredfeature but-
ton. More information on these secondary functions can
be found in the following text.
7

METER Block
METER
RANGE
I SUPPRESS ZERO CHECK CORR
I ClCo STORE Co
MEASUREMENT FUNCTIONS
CURRENT
The CURRENT buttonplacesthe Model 595 in thecurrent
measurement function. Any one
of eight ranges (20pA to
200pA) may be used with this function.
8

OPERATION
1. Enable ZERO CHECK.
2. Press CURRENT function button.
3. Select the appropriate range.
4. ZERO CORRect the instrument if it is not reading zero
5. Connect the signal to the rear panel and C.1 METER
6. Turn ZERO CHECK off.
(it is best todo this on the 20pA range).
INPUT.
CAPACITANCE, Q/t
The CAPACITANCE button places the Model 595 in the
capacitance measurement function. There are three
capacitance ranges: 20nF. 2nF, and 200pF.
OPERATION
1. Enable ZERO CHECK.
2. Press CAPAClTANCE button.
3. Select the desired range.
4. Connect the device to be measured between the rear
panelVOLTAGE SOURCEOUTPUT and C,I METER INPUT.
5. Turn ZERO CHECK off.
Qltdisplays the current flowing throughthe device at the
end of the delay time. Note: thecapacitancefunction must
be enabled to select Q/t.
9

OPERATION
1. Follow steps 1-5 under capacitance.
2. Press SHIFT, then Q/t to display Q/t.
SUPPRESS
The SUPPRESS buttonallows the user to compensate for
external offsets present inthe test set up by subtracting
the offset value from subsequent readings. Suppress may
be used with capacitance or current measurements, but
does notapply toQ/treadings. Theinstrumentcanbetog-
gled between
Q/t and capacitance without losingthestored
value.
OPERATION
1. Select desired function and range.
2. Input the offset or baseline level to the Model 595.
3. Press the SUPPRESS button. The SUPPRESS indicator
4. SUPPRESS can beturned off againby pressingtheSUP-
light
will turn on and the display will zero.
PRESS button.
C/Co - STORE CO
C/Co allows the user to normalizecapacitance to a stored
capacitance value
(C0L C/Co appliesonly tothecapacitance
reading (evenwhile Q/t is being displayed). Once a value
of
Co is stored, it will be retained in memory until a new
value is stored or the instrument is turned off.
10

OPERATION
1. Set up the desired capacitance measurement.
2. Press SHIFT, then STORE Co. The next reading will be
3. Press C/Co tonormalize thecapacitance readings to Co.
stored as Co.
The Range buttons select the desired range of measure-
mentfor the Model 595. Always usetherangethat allows
the greatest amount
of resolution.
OPERATION
1. To uprange, press the RANGE A button.
2. To downrange, press the RANGE V button.
ZERO CHECK and CORRect
Zero check is used to protect the input amplifier of the
Model 595from overloads andswitchingtransients when
changinginstrumentfunctions or connectionstothedevice
under test.
Zero check
is also usedwithzero correct to cancel internal
offsets
in theModel 595. Zero correction isnotapplicable
to capacitance or Q/t butshould beperformedfor the cur-
rent function onthe 20pA range. The zero correct value is
stored
in permanent memory.
11

OPERATION
1. Pressthe CURRENT buttonand select the 20pA range.
2. Press the ZERO CHECK button and be sure the ZERO
CHECK indicator light is on. The Model
595 input
amplifier isnow configured to read itsowninternaloffset.
3. Press SHIFT, then CORRect to zero correct the instru-
ment. Notethat ifzero check was notenabled, the zero
correct operation will enable zero check first.
4. The proper rangemay nowbeselectedand ZERO CHECK
released to make a measurement.
12

VOLTAGE SOURCE Block
f
VOLTAGE SOURCE
ALlMlT PRESET ADJUST
Ir
00
00 Or
FAST
VLlMlT PRESET
0
oL-n
DISPLAY SOURCE
DELAY TIME
FLASHES
00 DURING
\ 2mA MAX I-LIMIT
LIMIT, PRESET
The A, V LIMIT buttons set the maximum and minimum
voltagesthat the voltagesource will output to protect the
deviceundertest from destructivevoltagelevels. On power
up, the limits are set to
k20V.
PRESET allows the user to quickly set the output voltage
value to the maximumor minimum limit without usingthe
ADJUST buttons.
13

OPERATION
1. Press the LIMIT A or V button to display the upper or
lower voltage limit value.
2. Usethevoltage source ADJUST buttonsto change either
limit in 10mV increments.
3. To quickly setthe outputvoltage valuetothe maximum
or minimum limit, press SHIFT, then LIMIT PRESET
A
or V.
STEP V
Step V determines thestep size (asmall incremental change
in voltage) when either the square wave or staircase
waveform is selected. The step size may be &O.OlV,
?O.O2V, *O.OSV or
kO.1OV. When plotting a curve, step
V can beset
so thatthecurve contains thedesired number
of samples (the larger the step size, the fewer number of
samples in the curve).
OPERATION
1. Press STEP V to select the step voltage.
2. Select the step size with the ADJUST buttons.
3. To togglethe waveformbetweensquare wave and stair-
case, press SHIFT, then STEP V.
f, Front Panel Trigger
The ? buttonisusedto change the polarity of thevoltage
step and voltage source. This button can also be used to
trigger a single reading from
the front panel.
14

OPERATION
1. Press STEP V to display the step voltage or DISPLAY
SOURCE to display the programmed output voltage.
2. Press -c to change the polarity of the displayed value.
Note: PressingSHIFT, then * will trigger a measurement
from thefront panel. This is convenient ifan externaltrig-
ger source is unavailable.
DELAY TIME
Thetimefromthevoltage steptothefinal charge measure-
mentfor acapacitancecalculation, or from the step tothe
measurement in current, is the delay time. Delay time,
0.07sec to 199.99sec. is used to allow the device under
test to respond to the change in step voltage before the
measurement. Delay time is important when performing
capacitance and CV measurements on MOS capacitors
(DelayTime must be long enough for the device to reach
equilibrium). It is not as critical when performing simple
capacitance, current, or IV measurements.
Figure 1 shows ingreater detail where the delay time OC-
curs. The total time of the voltage step is delay time plus
T1. IT1 isthe period necessary for the Model 595 tofinish
themeasurement, and istypically 0.04sec.) The totaltime
of the voltage step (delay time plus T1 time) is calledthe
step time.
15