Acknowledgments
Our sincerest appreciation must be extended to the instructors who have used the text
and sent in comments, corrections, and suggestions. We also want to thank Rex David-
son, Production Editor at Prentice Hall, for keeping together the many detailed as-
pects of production. Our sincerest thanks to Dave Garza, Senior Editor, and Linda
Ludewig, Editor, at Prentice Hall for their editorial support of the Seventh Edition of
this text.
We wish to thank those individuals who have shared their suggestions and evalua-
tions of this text throughout its many editions. The comments from these individu-
als have enabled us to present Electronic Devices and Circuit Theory in this Seventh
Edition:
Ernest Lee Abbott Napa College, Napa, CA
Phillip D. Anderson Muskegon Community College, Muskegon, MI
Al Anthony EG&G VACTEC Inc.
A. Duane Bailey Southern Alberta Institute of Technology, Calgary, Alberta, CANADA
Joe Baker University of Southern California, Los Angeles, CA
Jerrold Barrosse Penn State–Ogontz
Ambrose Barry University of North Carolina–Charlotte
Arthur Birch Hartford State Technical College, Hartford, CT
Scott Bisland SEMATECH, Austin, TX
Edward Bloch The Perkin-Elmer Corporation
Gary C. Bocksch Charles S. Mott Community College, Flint, MI
Jeffrey Bowe Bunker Hill Community College, Charlestown, MA
Alfred D. Buerosse Waukesha County Technical College, Pewaukee, WI
Lila Caggiano MicroSim Corporation
Mauro J. Caputi Hofstra University
Robert Casiano International Rectifier Corporation
Alan H. Czarapata Montgomery College, Rockville, MD
Mohammad Dabbas ITT Technical Institute
John Darlington Humber College, Ontario, CANADA
Lucius B. Day Metropolitan State College, Denver, CO
Mike Durren Indiana Vocational Technical College, South Bend, IN
Dr. Stephen Evanson Bradford University, UK
George Fredericks Northeast State Technical Community College, Blountville, TN
F. D. Fuller Humber College, Ontario, CANADA
xvii
, Phil Golden DeVry Institute of Technology, Irving, TX
Joseph Grabinski Hartford State Technical College, Hartfold, CT
Thomas K. Grady Western Washington University, Bellingham, WA
William Hill ITT Technical Institute
Albert L. Ickstadt San Diego Mesa College, San Diego, CA
Jeng-Nan Juang Mercer University, Macon, GA
Karen Karger Tektronix Inc.
Kenneth E. Kent DeKalb Technical Institute, Clarkston, GA
Donald E. King ITT Technical Institute, Youngstown, OH
Charles Lewis APPLIED MATERIALS, INC.
Donna Liverman Texas Instruments Inc.
William Mack Harrisburg Area Community College
Robert Martin Northern Virginia Community College
George T. Mason Indiana Vocational Technical College, South Bend, IN
William Maxwell Nashville State Technical Institute
Abraham Michelen Hudson Valley Community College
John MacDougall University of Western Ontario, London, Ontario,
CANADA
Donald E. McMillan Southwest State University, Marshall, MN
Thomas E. Newman L. H. Bates Vocational-Technical Institute, Tacoma, WA
Byron Paul Bismarck State College
Dr. Robert Payne University of Glamorgan, Wales, UK
Dr. Robert A. Powell Oakland Community College
E. F. Rockafellow Southern-Alberta Institute of Technology, Calgary,
Alberta, CANADA
Saeed A. Shaikh Miami-Dade Community College, Miami, FL
Dr. Noel Shammas School of Engineering, Beaconside, UK
Ken Simpson Stark State College of Technology
Eric Sung Computronics Technology Inc.
Donald P. Szymanski Owens Technical College, Toledo, OH
Parker M. Tabor Greenville Technical College, Greenville, SC
Peter Tampas Michigan Technological University, Houghton, MI
Chuck Tinney University of Utah
Katherine L. Usik Mohawk College of Applied Art & Technology,
Hamilton, Ontario, CANADA
Domingo Uy Hampton University, Hampton, VA
Richard J. Walters DeVry Technical Institute, Woodbridge, NJ
Larry J. Wheeler PSE&G Nuclear
Julian Wilson Southern College of Technology, Marietta, GA
Syd R. Wilson Motorola Inc.
Jean Younes ITT Technical Institute, Troy, MI
Charles E. Yunghans Western Washington University, Bellingham, WA
Ulrich E. Zeisler Salt Lake Community College, Salt Lake City, UT
xviii Acknowledgments
, p n
CHAPTER
Semiconductor
Diodes 1
1.1 INTRODUCTION
It is now some 50 years since the first transistor was introduced on December 23,
1947. For those of us who experienced the change from glass envelope tubes to the
solid-state era, it still seems like a few short years ago. The first edition of this text
contained heavy coverage of tubes, with succeeding editions involving the important
decision of how much coverage should be dedicated to tubes and how much to semi-
conductor devices. It no longer seems valid to mention tubes at all or to compare the
advantages of one over the other—we are firmly in the solid-state era.
The miniaturization that has resulted leaves us to wonder about its limits. Com-
plete systems now appear on wafers thousands of times smaller than the single ele-
ment of earlier networks. New designs and systems surface weekly. The engineer be-
comes more and more limited in his or her knowledge of the broad range of advances—
it is difficult enough simply to stay abreast of the changes in one area of research or
development. We have also reached a point at which the primary purpose of the con-
tainer is simply to provide some means of handling the device or system and to pro-
vide a mechanism for attachment to the remainder of the network. Miniaturization
appears to be limited by three factors (each of which will be addressed in this text):
the quality of the semiconductor material itself, the network design technique, and
the limits of the manufacturing and processing equipment.
1.2 IDEAL DIODE
The first electronic device to be introduced is called the diode. It is the simplest of
semiconductor devices but plays a very vital role in electronic systems, having char-
acteristics that closely match those of a simple switch. It will appear in a range of ap-
plications, extending from the simple to the very complex. In addition to the details
of its construction and characteristics, the very important data and graphs to be found
on specification sheets will also be covered to ensure an understanding of the termi-
nology employed and to demonstrate the wealth of information typically available
from manufacturers.
The term ideal will be used frequently in this text as new devices are introduced.
It refers to any device or system that has ideal characteristics—perfect in every way.
It provides a basis for comparison, and it reveals where improvements can still be
made. The ideal diode is a two-terminal device having the symbol and characteris- Figure 1.1 Ideal diode: (a)
tics shown in Figs. 1.1a and b, respectively. symbol; (b) characteristics.
1
, p n
Ideally, a diode will conduct current in the direction defined by the arrow in the
symbol and act like an open circuit to any attempt to establish current in the oppo-
site direction. In essence:
The characteristics of an ideal diode are those of a switch that can conduct
current in only one direction.
In the description of the elements to follow, it is critical that the various letter
symbols, voltage polarities, and current directions be defined. If the polarity of the
applied voltage is consistent with that shown in Fig. 1.1a, the portion of the charac-
teristics to be considered in Fig. 1.1b is to the right of the vertical axis. If a reverse
voltage is applied, the characteristics to the left are pertinent. If the current through
the diode has the direction indicated in Fig. 1.1a, the portion of the characteristics to
be considered is above the horizontal axis, while a reversal in direction would require
the use of the characteristics below the axis. For the majority of the device charac-
teristics that appear in this book, the ordinate (or “y” axis) will be the current axis,
while the abscissa (or “x” axis) will be the voltage axis.
One of the important parameters for the diode is the resistance at the point or re-
gion of operation. If we consider the conduction region defined by the direction of ID
and polarity of VD in Fig. 1.1a (upper-right quadrant of Fig. 1.1b), we will find that
the value of the forward resistance, RF, as defined by Ohm’s law is
VF 0V
RF 0 (short circuit)
IF 2, 3, mA, . . . , or any positive value
where VF is the forward voltage across the diode and IF is the forward current through
the diode.
The ideal diode, therefore, is a short circuit for the region of conduction.
Consider the region of negatively applied potential (third quadrant) of Fig. 1.1b,
VR 5, 20, or any reverse-bias potential
RR (open-circuit)
IR 0 mA
where VR is reverse voltage across the diode and IR is reverse current in the diode.
The ideal diode, therefore, is an open circuit in the region of nonconduction.
In review, the conditions depicted in Fig. 1.2 are applicable.
VD Short circuit
+ – ID
I D (limited by circuit)
(a)
0 VD
VD Open circuit
– +
ID = 0
(b)
Figure 1.2 (a) Conduction and (b) nonconduction states of the ideal diode as
determined by the applied bias.
In general, it is relatively simple to determine whether a diode is in the region of
conduction or nonconduction simply by noting the direction of the current ID estab-
lished by an applied voltage. For conventional flow (opposite to that of electron flow),
if the resultant diode current has the same direction as the arrowhead of the diode
symbol, the diode is operating in the conducting region as depicted in Fig. 1.3a. If
2 Chapter 1 Semiconductor Diodes
Our sincerest appreciation must be extended to the instructors who have used the text
and sent in comments, corrections, and suggestions. We also want to thank Rex David-
son, Production Editor at Prentice Hall, for keeping together the many detailed as-
pects of production. Our sincerest thanks to Dave Garza, Senior Editor, and Linda
Ludewig, Editor, at Prentice Hall for their editorial support of the Seventh Edition of
this text.
We wish to thank those individuals who have shared their suggestions and evalua-
tions of this text throughout its many editions. The comments from these individu-
als have enabled us to present Electronic Devices and Circuit Theory in this Seventh
Edition:
Ernest Lee Abbott Napa College, Napa, CA
Phillip D. Anderson Muskegon Community College, Muskegon, MI
Al Anthony EG&G VACTEC Inc.
A. Duane Bailey Southern Alberta Institute of Technology, Calgary, Alberta, CANADA
Joe Baker University of Southern California, Los Angeles, CA
Jerrold Barrosse Penn State–Ogontz
Ambrose Barry University of North Carolina–Charlotte
Arthur Birch Hartford State Technical College, Hartford, CT
Scott Bisland SEMATECH, Austin, TX
Edward Bloch The Perkin-Elmer Corporation
Gary C. Bocksch Charles S. Mott Community College, Flint, MI
Jeffrey Bowe Bunker Hill Community College, Charlestown, MA
Alfred D. Buerosse Waukesha County Technical College, Pewaukee, WI
Lila Caggiano MicroSim Corporation
Mauro J. Caputi Hofstra University
Robert Casiano International Rectifier Corporation
Alan H. Czarapata Montgomery College, Rockville, MD
Mohammad Dabbas ITT Technical Institute
John Darlington Humber College, Ontario, CANADA
Lucius B. Day Metropolitan State College, Denver, CO
Mike Durren Indiana Vocational Technical College, South Bend, IN
Dr. Stephen Evanson Bradford University, UK
George Fredericks Northeast State Technical Community College, Blountville, TN
F. D. Fuller Humber College, Ontario, CANADA
xvii
, Phil Golden DeVry Institute of Technology, Irving, TX
Joseph Grabinski Hartford State Technical College, Hartfold, CT
Thomas K. Grady Western Washington University, Bellingham, WA
William Hill ITT Technical Institute
Albert L. Ickstadt San Diego Mesa College, San Diego, CA
Jeng-Nan Juang Mercer University, Macon, GA
Karen Karger Tektronix Inc.
Kenneth E. Kent DeKalb Technical Institute, Clarkston, GA
Donald E. King ITT Technical Institute, Youngstown, OH
Charles Lewis APPLIED MATERIALS, INC.
Donna Liverman Texas Instruments Inc.
William Mack Harrisburg Area Community College
Robert Martin Northern Virginia Community College
George T. Mason Indiana Vocational Technical College, South Bend, IN
William Maxwell Nashville State Technical Institute
Abraham Michelen Hudson Valley Community College
John MacDougall University of Western Ontario, London, Ontario,
CANADA
Donald E. McMillan Southwest State University, Marshall, MN
Thomas E. Newman L. H. Bates Vocational-Technical Institute, Tacoma, WA
Byron Paul Bismarck State College
Dr. Robert Payne University of Glamorgan, Wales, UK
Dr. Robert A. Powell Oakland Community College
E. F. Rockafellow Southern-Alberta Institute of Technology, Calgary,
Alberta, CANADA
Saeed A. Shaikh Miami-Dade Community College, Miami, FL
Dr. Noel Shammas School of Engineering, Beaconside, UK
Ken Simpson Stark State College of Technology
Eric Sung Computronics Technology Inc.
Donald P. Szymanski Owens Technical College, Toledo, OH
Parker M. Tabor Greenville Technical College, Greenville, SC
Peter Tampas Michigan Technological University, Houghton, MI
Chuck Tinney University of Utah
Katherine L. Usik Mohawk College of Applied Art & Technology,
Hamilton, Ontario, CANADA
Domingo Uy Hampton University, Hampton, VA
Richard J. Walters DeVry Technical Institute, Woodbridge, NJ
Larry J. Wheeler PSE&G Nuclear
Julian Wilson Southern College of Technology, Marietta, GA
Syd R. Wilson Motorola Inc.
Jean Younes ITT Technical Institute, Troy, MI
Charles E. Yunghans Western Washington University, Bellingham, WA
Ulrich E. Zeisler Salt Lake Community College, Salt Lake City, UT
xviii Acknowledgments
, p n
CHAPTER
Semiconductor
Diodes 1
1.1 INTRODUCTION
It is now some 50 years since the first transistor was introduced on December 23,
1947. For those of us who experienced the change from glass envelope tubes to the
solid-state era, it still seems like a few short years ago. The first edition of this text
contained heavy coverage of tubes, with succeeding editions involving the important
decision of how much coverage should be dedicated to tubes and how much to semi-
conductor devices. It no longer seems valid to mention tubes at all or to compare the
advantages of one over the other—we are firmly in the solid-state era.
The miniaturization that has resulted leaves us to wonder about its limits. Com-
plete systems now appear on wafers thousands of times smaller than the single ele-
ment of earlier networks. New designs and systems surface weekly. The engineer be-
comes more and more limited in his or her knowledge of the broad range of advances—
it is difficult enough simply to stay abreast of the changes in one area of research or
development. We have also reached a point at which the primary purpose of the con-
tainer is simply to provide some means of handling the device or system and to pro-
vide a mechanism for attachment to the remainder of the network. Miniaturization
appears to be limited by three factors (each of which will be addressed in this text):
the quality of the semiconductor material itself, the network design technique, and
the limits of the manufacturing and processing equipment.
1.2 IDEAL DIODE
The first electronic device to be introduced is called the diode. It is the simplest of
semiconductor devices but plays a very vital role in electronic systems, having char-
acteristics that closely match those of a simple switch. It will appear in a range of ap-
plications, extending from the simple to the very complex. In addition to the details
of its construction and characteristics, the very important data and graphs to be found
on specification sheets will also be covered to ensure an understanding of the termi-
nology employed and to demonstrate the wealth of information typically available
from manufacturers.
The term ideal will be used frequently in this text as new devices are introduced.
It refers to any device or system that has ideal characteristics—perfect in every way.
It provides a basis for comparison, and it reveals where improvements can still be
made. The ideal diode is a two-terminal device having the symbol and characteris- Figure 1.1 Ideal diode: (a)
tics shown in Figs. 1.1a and b, respectively. symbol; (b) characteristics.
1
, p n
Ideally, a diode will conduct current in the direction defined by the arrow in the
symbol and act like an open circuit to any attempt to establish current in the oppo-
site direction. In essence:
The characteristics of an ideal diode are those of a switch that can conduct
current in only one direction.
In the description of the elements to follow, it is critical that the various letter
symbols, voltage polarities, and current directions be defined. If the polarity of the
applied voltage is consistent with that shown in Fig. 1.1a, the portion of the charac-
teristics to be considered in Fig. 1.1b is to the right of the vertical axis. If a reverse
voltage is applied, the characteristics to the left are pertinent. If the current through
the diode has the direction indicated in Fig. 1.1a, the portion of the characteristics to
be considered is above the horizontal axis, while a reversal in direction would require
the use of the characteristics below the axis. For the majority of the device charac-
teristics that appear in this book, the ordinate (or “y” axis) will be the current axis,
while the abscissa (or “x” axis) will be the voltage axis.
One of the important parameters for the diode is the resistance at the point or re-
gion of operation. If we consider the conduction region defined by the direction of ID
and polarity of VD in Fig. 1.1a (upper-right quadrant of Fig. 1.1b), we will find that
the value of the forward resistance, RF, as defined by Ohm’s law is
VF 0V
RF 0 (short circuit)
IF 2, 3, mA, . . . , or any positive value
where VF is the forward voltage across the diode and IF is the forward current through
the diode.
The ideal diode, therefore, is a short circuit for the region of conduction.
Consider the region of negatively applied potential (third quadrant) of Fig. 1.1b,
VR 5, 20, or any reverse-bias potential
RR (open-circuit)
IR 0 mA
where VR is reverse voltage across the diode and IR is reverse current in the diode.
The ideal diode, therefore, is an open circuit in the region of nonconduction.
In review, the conditions depicted in Fig. 1.2 are applicable.
VD Short circuit
+ – ID
I D (limited by circuit)
(a)
0 VD
VD Open circuit
– +
ID = 0
(b)
Figure 1.2 (a) Conduction and (b) nonconduction states of the ideal diode as
determined by the applied bias.
In general, it is relatively simple to determine whether a diode is in the region of
conduction or nonconduction simply by noting the direction of the current ID estab-
lished by an applied voltage. For conventional flow (opposite to that of electron flow),
if the resultant diode current has the same direction as the arrowhead of the diode
symbol, the diode is operating in the conducting region as depicted in Fig. 1.3a. If
2 Chapter 1 Semiconductor Diodes
