Electronic device, in particular for switching electric currents, for high reverse voltages and with low on-state losses

A p-n junction is connected between two terminals. The p-n junction is formed between two semiconductor regions of a semiconductor with a breakdown field strength of at least 10.sup.6 V/cm. A channel region, which adjoins the p-n junction is connected in series with a silicon component between the two terminals. The channel region is provided in a first of the two semiconductor regions. A depletion zone of the p-n junction carries the reverse voltage in the off state of the silicon component. The silicon component is preferably a

BACKGROUND OF THE INVENTION 
Field of the Invention: 
The invention relates to electronic devices, and particularly to electronic 
switching devices. 
Semiconductor components are used in addition to mechanical switchgear for 
switching electric currents. Semiconductor components can be divided into 
current-controlled semiconductor components, including bipolar transistors 
and thyristors, on the one hand, and voltage-controlled semiconductor 
components such as, for example, the unipolar MOS (Metal Oxide 
Semiconductor) field-effect transistors (MOSFET), or the bipolar 
MOS-controlled thyristors (MCT), or the MOS-controlled bipolar transistors 
(IGBT), on the other hand. All of these semiconductor components can only 
switch currents in one current direction, that is to say only for a 
specific polarity of the operating voltage (switchable state). In the 
switchable state, by alteration of the control voltage or of the control 
current, the semiconductor component can be switched from an off state, in 
which virtually no current flows through the semiconductor component, into 
an on state, in which a current flows through the semiconductor component, 
or vice versa. In the on state, the current flowing through the 
semiconductor component is dependent on the magnitude of the operating 
voltage and the driving control voltage or the driving control current. In 
its off state, each semiconductor component can be reverse-biased only up 
to a maximum reverse voltage (breakdown voltage). A charge carrier 
breakdown occurs at higher reverse voltages and may rapidly lead to the 
destruction of the component. For alternating currents, two semiconductor 
components are, as a rule, reverse-connected in parallel (bidirectional 
connection). 
Silicon (Si) is used, in practice, as the semiconductor material for 
semiconductor components, in particular for power electronics. One of the 
reasons is that silicon process technology is highly developed. Also, 
voltage-controlled MOS semiconductor components using silicon have high 
switching speeds owing to the high charge carrier mobility of silicon in 
the channel region of the MOS structure. One problem of MOSFETs is that 
the steady-state losses in the on state become higher, the higher the 
reverse voltages to be managed by the MOSFET in the off state are. In 
silicon, the steady-state power loss of a power MOSFET which is designed 
for high reverse voltages starting from about 600 V becomes so high at 
forward currents starting typically from about 5 A that bipolar IGBTs in 
silicon are preferred to the silicon MOSFETs for these and higher 
switching currents and reverse voltages. 
The international publication WO 95/24055 discloses a MOSFET which is 
formed in the semiconductor material of silicon carbide (SiC). Given the 
same blocking capability of more than 600 V, such a silicon carbide MOSFET 
can be designed with lower on-state losses than a silicon MOSFET. However, 
the process technology in silicon carbide, in particular for the MOS 
structure, is not yet as advanced as in silicon. The result is that 
silicon carbide MOSFETs are not yet mass produced. 
SUMMARY OF THE INVENTION 
It is accordingly an object of the invention to provide an electronic 
device for high blocking voltages and low on-state power losses, which 
overcomes the above-mentioned disadvantages of the heretofore-known 
devices and methods of this general type and which can be laid out for 
high reverse voltages of more than 500 V yet has only low losses in the 
on-state mode. 
With the foregoing and other objects in view there is provided, in 
accordance with the invention, an electronic device, particularly for 
switching electrical currents, comprising: 
two electrical terminals for connecting electrical operating voltages with 
maximum values of above 500 V; 
a silicon component connected between the two electrical terminals and 
being selectively in an on state or an off state depending on a 
predetermined polarity of the operating voltages; 
a semiconductor configuration made of silicon carbide with a first 
semiconductor region of a predetermined conductivity type and with at 
least one further semiconductor region of an opposite conductivity type; 
the semiconductor configuration and the silicon component together forming 
an integrated hybrid component; 
a p-n junction formed between the first semiconductor region and the at 
least one further semiconductor region; 
the first semiconductor region having at least one channel region adjacent 
the p-n junction and electrically connected in series with the silicon 
component between the two terminals; 
the p-n junction being electrically connected between the two terminals in 
a reverse direction for the operating voltage of the predetermined 
polarity; and 
a depletion zone of the p-n junction pinching off or covering the at least 
one channel region of the first semiconductor region in the off state of 
the silicon component. 
The invention is based on the premise of combining the good controllability 
and the diverse embodiments of silicon components, in particular for power 
switching technology, with the high blocking capability of a p-n junction 
in a semiconductor with a breakdown field strength of at least 10.sup.6 
V/cm (volts per centimeter) in a particular and advantageous manner. The 
breakdown field strength is the maximum field strength permitted to occur 
in a semiconductor without destroying the semiconductor by a charge 
carrier breakdown. 
In summary, the electronic device has two electrical terminals for the 
application of electrical operating voltages, a silicon-based 
semiconductor component and, in addition, a semiconductor configuration. 
The semiconductor configuration comprises a first semiconductor region of 
a first conductivity type and at least one further semiconductor region of 
an opposite, second conductivity type. The semiconductor regions are each 
formed by a semiconductor with a breakdown field strength at least 
10.sup.6 V/cm. A p-n junction is formed in each case between the 
oppositely conducting semiconductor regions. At least one channel region, 
adjoining the p-n junction, in the first semiconductor region of the 
semiconductor configuration is then electrically connected in series with 
the silicon component between the two terminals. At operating voltages of 
a predetermined polarity, the silicon component has an on state and an off 
state. An electric current flows through the silicon component in the on 
state, while a virtually negligible reverse current flows in the off 
state. The p-n junction of the semiconductor configuration is electrically 
connected between the two terminals in the reverse direction for the 
operating voltages with the predetermined polarity. When the silicon 
component is in its off state, the depletion zone of the at least one p-n 
junction pinches off the channel region in the first semiconductor region 
or even covers the entire channel region. Owing to the substantially 
higher electrical resistance of the depletion zone in comparison with the 
channel region, a large proportion of the operating voltage between the 
two terminals is already dropped across the depletion zone of the p-n 
junction in the off state of the silicon component. On account of the high 
breakdown field strength of at least 10.sup.6 V/cm of the semiconductor 
which is provided for the semiconductor regions of the p-n junction, the 
p-n junction of the semiconductor configuration can carry distinctly 
higher reverse voltages than a p-n junction having the same charge carrier 
concentrations and dimensions which is formed in silicon. For comparison, 
the breakdown field strength of silicon is about 2.multidot.10.sup.5 V/cm. 
Therefore, the silicon component only has to be designed for the remaining 
part of the reverse voltage between the two terminals. This in turn has 
the consequence of a distinctly reduced power loss of the silicon 
component in the on-state mode. Furthermore, in the other circuit path, 
the entire operating voltage between the two terminals is applied as 
reverse voltage to the p-n junction of the semiconductor configuration. 
In the on state of the silicon component, the depletion zone of the p-n 
junction is flooded with charge carriers and the channel region in the 
first semiconductor region of the semiconductor configuration is opened 
again. An electric current can then flow through the channel region 
between the two terminals. The total power loss of the electronic device 
in the on-state mode (current-carrying mode) comprises the losses in the 
silicon component in the on state and the losses in the first 
semiconductor region of the semiconductor configuration. At a 
predetermined maximum reverse voltage, these total losses of the 
electronic device are distinctly lower than in the case of a silicon 
component which is of the same structural type and is designed for this 
maximum reverse voltage, when considered solely by itself. They are also 
lower than in the case of a semiconductor component which is designed for 
the predetermined maximum reverse voltage, is of the same structural type 
as the silicon component and is formed in the same semiconductor as the 
semiconductor configuration. 
In accordance with an added feature of the invention, the first 
semiconductor region has a first surface and the at least one further 
semiconductor region is arranged on the first surface, preferably by means 
of ion implantation. This embodiment is advantageous in respect of 
production, 
In accordance with an additional feature of the invention, the first 
semiconductor region has a second surface opposite the first surface of 
the first semiconductor region, and an electrode disposed on the second 
surface. The electrode can be electrically connected to one pole of the 
operating voltage. 
In an alternative embodiment, a further semiconductor region of an opposite 
conductivity type is disposed on the second surface, and an electrode is 
disposed on a surface of the further semiconductor region that is remote 
from the first semiconductor region. Again, the electrode can be 
electrically connected to a pole of the operating voltage. In this 
embodiment, an additional p-n junction is connected between the two 
terminals of the electronic device. 
In accordance with a particularly advantageous feature of the invention, 
the semiconductor configuration further comprises at least two further 
semiconductor regions of an opposite conductivity type to the first 
semiconductor region, and where each of the two further semiconductor 
regions forms a respective one of two p-n junctions with the first 
semiconductor region, and the at least one channel region is bounded by 
the two p-n junctions. In the off state of the silicon component, the 
depletion zones of the p-n junctions merge and thus terminate the channel 
region as common depletion zone. 
A preferred semiconductor material for the semiconductor configuration is 
silicon carbide (SiC). Silicon carbide is particularly suited owing to its 
outstanding electronic and thermal properties. 
Since a semiconductor with a high breakdown field strength generally also 
has a high energy gap between valence band and conduction band, the 
semiconductor configuration can be designed for higher current densities 
than the silicon component and, consequently, the total area and the 
material requirement of the semiconductor configuration can be reduced. 
The greater heating of the semiconductor configuration associated with the 
higher current densities does not have a disadvantageous effect owing to 
the temperature strength of the semiconductor of the semiconductor 
configuration on account of the high energy gap of the semiconductor. 
In accordance with a further feature of the invention, the silicon 
component contains a MOS structure controlling the current flow and thus 
for switching between the on state and the off state. The high MOS channel 
mobility of the charge carriers in silicon is utilized in this embodiment. 
In accordance with a concomitant feature of the invention, the silicon 
component is a unipolar silicon MOSFET. 
Other features which are considered as characteristic for the invention are 
set forth in the appended claims. 
Although the invention is illustrated and described herein as embodied in 
an electronic device, in particular for switching electronic currents, for 
high off-state voltages and with low on-state power losses, it is 
nevertheless not intended to be limited to the details shown, since 
various modifications and structural changes may be made therein without 
departing from the spirit of the invention and within the scope and range 
of equivalents of the claims. 
The construction and method of operation of the invention, however, 
together with additional objects and advantages thereof will be best 
understood from the following description of specific embodiments when 
read in connection with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the figures of the drawing in detail, wherein like 
components are identified with like reference numerals, and first, 
particularly, to the sketched circuit diagram of FIG. 1 thereof, there is 
seen a fundamental structure of the electronic device 1. The electronic 
device comprises two electrical terminals 2 and 3, a silicon component 
(semiconductor component based on the semiconductor silicon) 4 and a 
semiconductor configuration 5. An operating voltage U is applied between 
the two terminals 2 and 3 during operation of the electronic device, which 
voltage may be constant with respect to time or it may be variable. 
The silicon component 4 has a first terminal 4A, a second electrical 
terminal 4B, and a control terminal 4C. Given a specific polarity of a 
voltage U.sub.2 between the terminals 4A and 4B, the silicon component is 
in a switchable state (switching state, switching direction) and, in 
dependence on a control voltage U.sub.c at the control terminal 4C, or a 
control current, can switch through or switch off an electric current 
between the two terminals 4A and 4B. With the aid of the control voltage 
U.sub.c or the control current, therefore, the silicon component 4 can, at 
the predetermined polarity of the voltage U.sub.2, be brought from an on 
state (current-carrying state) to an off state (zero-current state), or 
vice versa. At the opposite polarity of the voltage U2 between the two 
terminals 4A and 4B, the silicon component 4 is in a non-switchable state 
and can then no longer be controlled by the control voltage U.sub.c or the 
control current. 
The semiconductor configuration 5 comprises a first semiconductor region 6 
of one conductivity type and at least one further semiconductor region 8 
adjacent the first semiconductor region 6. The region 8 has an opposite 
conductivity as compared to the first semiconductor region 6. The 
semiconductor regions 6 and 8 of the semiconductor configuration 5 are 
each composed of a semiconductor material with a breakdown field strength 
of at least 10.sup.6 V/cm. Suitable semiconductor materials are diamond, 
aluminum nitride (AlN), gallium nitride (GaN), indium nitride (InN) and, 
preferably, silicon carbide (SiC), preferably of the polytypes 4H and/or 
6H. A p-n junction 7 is formed, with a depletion zone (space charge zone, 
depletion layer) 70, between the two semiconductor regions 6 and 8. The 
depletion zone 70 is produced by charge carrier diffusion between the two 
semiconductor regions 6 and 8 and is distinguished by a very high 
electrical resistance in comparison with the semiconductor regions 6 and 
8. The extent of the depletion zone 70 depends on a voltage (potential 
difference) between the two semiconductor regions 6 and 8. That voltage is 
present at the p-n junction 7. 
The first semiconductor region 6 is assigned two electrical contacts 5A and 
5B of the semiconductor configuration 5. The contacts are connected to one 
another via a channel region 9 in the first semiconductor region 6. The 
channel region 9 is bounded in its extent by the depletion zone 70 of the 
p-n junction 7. The second semiconductor region 8 is assigned a further 
contact 5C of the semiconductor configuration 5. The contat 5C connects 
the second semiconductor region 8 to the first terminal 2 of the 
electronic device. The first contact 5A at the channel region 9 is 
electrically connected to the second terminal 4B of the silicon component 
4. The first terminal 4A of the silicon component 4 is electrically 
connected to the first terminal 2 of the electronic device. Consequently, 
the silicon component 4 and the channel region 9 are electrically 
connected in series between the two terminals 2 and 3 of the electronic 
device. The second contact 5B of the semiconductor configuration 5 at the 
channel region 9 is electrically connected to the second terminal 3 of the 
electronic device. As a result, the p-n junction 7 is electrically 
connected between the two terminals 2 and 3. 
The conductivity types of the semiconductor regions 6 and 8 forming the p-n 
junction 7 are chosen in such a way that the p-n junction 7 of the 
semiconductor configuration 5 blocks when an operating voltage U in the 
switching direction for the silicon component 4 is present at the 
terminals 2 and 3. Since the p-n junction 7 is thus reverse-biased in 
particular even when the silicon component 4 is in the off state, its 
depletion zone 70 carries virtually the entire reverse voltage U between 
the terminals 2 and 3 up to a maximum value of the reverse voltage, the 
so-called breakdown voltage. In the exemplary embodiment of FIG. 1, it is 
assumed that the silicon component 4 is biased (switched) in the switching 
direction when the electrical potential at its first terminal 4A is 
negative relative to the potential at its second terminal 4B. This 
corresponds to the case where the negative pole of the operating voltage U 
is present at the first terminal 2 of the electronic device and the 
positive pole of the operating voltage U at the second terminal 3. 
Consequently, the first semiconductor region 6, electrically connected to 
the second terminal 3, of the semiconductor configuration 5 is thus chosen 
to be n-conducting and the second semiconductor region 8, electrically 
connected to the first terminal 2, of the semiconductor configuration 5 is 
thus chosen to be p-conducting. In the case of reversed polarity 
(directionality) of the silicon component 4, it is indeed necessary to 
interchange the conductivity types of the two semiconductor regions 6 and 
8 forming the p-n junction 7. 
If the small voltage drops of the electrical connections are ignored, then 
the operating voltage U in the circuit path with the silicon component 4 
is divided into two voltage components U.sub.1 and U.sub.2. The first 
voltage component U.sub.1 is dropped between the contacts 5A and 5B of the 
semiconductor configuration 5. The second voltage component U.sub.2 is 
dropped between the terminals 4A and 4B of the silicon component 4. In the 
other circuit path, virtually the total operating voltage U is dropped 
across the depletion zone 70 of the p-n junction 7 of the semiconductor 
configuration 5. 
The silicon component 4 is illustrated in its on state in FIG. 1, indicated 
by the closed switch contact. Since an electric current I then flows 
through the silicon component 4, charge carriers are injected into the 
depletion zone 70 of the p-n junction 7. As a result, the depletion zone 
70 retreats and has a comparatively small extent determined by the 
remaining reverse voltage between the contacts 5B and 5C. The channel 
region 9 is thus opened, and the electric current I can flow through the 
series circuit formed by the silicon component 4 and the channel region 9 
of the first semiconductor region 6 of the semiconductor configuration 5. 
In this case, the channel region 9 of the semiconductor configuration 5 is 
available, in general, virtually completely as a current path for the 
electric current I. 
If the silicon component 4 is then brought into its off state by altering 
the control voltage U.sub.c at the same polarity of the operating voltage 
U, then the depletion zone 70 of the p-n junction 7 expands and interrupts 
the current path (electrically semiconducting region) in the channel 
region 9. As a result of the depletion of charge carriers, the channel 
region 9 may either be pinched off by the depletion zone 70, that is to 
say interrupted at least in a partial region transversely to the current 
direction, or even be completely covered. For this purpose, the 
geometrical dimensions of the first semiconductor region 6 and of the 
second semiconductor region 8 and the charge carrier concentrations to be 
set by way of the doping in the two semiconductor regions 6 and 8 are 
preferably chosen in such a way that the electrical potential at the 
contact 5A of the semiconductor configuration 5 is always less than the 
breakdown voltage (maximum reverse voltage) U.sub.max of the silicon 
component 4. It is then ensured that a wide partial zone of the depletion 
zone 70 sufficient for the breakdown voltage U.sub.max predetermined by 
the silicon component 4 is electrically connected between the contacts 5A 
and 5B and the silicon component 4 is not destroyed. The first 
semiconductor region 6 is preferably more weakly doped than the second 
semiconductor region 8, at least in the channel region 9. The depletion 
zone 70 of the p-n junction 7 then expands to a greater extent into the 
first semiconductor region 6, with the advantage of better drivability of 
the control of the bulk resistance of the channel region 9 by the 
depletion zone 70. A voltage component U.sub.1 of the operating voltage U, 
acting as reverse voltage, is then dropped across the depletion zone 70, 
having a high electrical resistance, between the contacts 5A and 5B of the 
semiconductor configuration 5. 
The silicon component 4 may be a commercially available silicon-based 
semiconductor component, preferably a voltage-controlled MOS (metal oxide 
semiconductor) component (power MOS device). In the case of a MOS 
voltage-controlled silicon component 4, the control terminal 4C is the 
gate terminal of the MOS structure. A power MOSFET (metal oxide 
semiconductor field effect transistor) in silicon, preferably of the 
normally off type, is particularly suitable as the silicon component 4. 
Alternatively, a silicon MESFET (metal semiconductor field effect 
transistor) can be used as the silicon component 4. 
Since the semiconductor configuration 5 takes over the voltage component 
U.sub.1 of the operating reverse voltage U in the off state of the silicon 
component 4, the silicon component 4 needs no longer to be designed for 
the entire maximum operating reverse voltage U.sub.max. The semiconductor 
configuration 5 is preferably designed for the maximum operating voltage 
U.sub.max between the two terminals 2 and 3 of the electronic device. The 
silicon component 4 is generally designed for a maximum reverse voltage 
(breakdown voltage) at its two terminals 4A and 4B of less than 350 V, in 
particular less than 100 V, and preferably less than 50 V. For example, a 
Siemens type BSM 101 AR MOSFET with a maximum reverse voltage of 50 V, a 
forward resistance of 3 m.OMEGA. and a desired rated current-carrying 
capacity in the on-state mode may be used. At breakdown voltages of less 
than about 350 V, the channel resistance of the MOS structure is greater 
than the drift resistance in the silicon component 4. Preferably, the 
breakdown voltage of the silicon component 4 is chosen to be low enough 
that the drift resistance of the silicon component 4 is negligible 
relative to the channel resistance thereof, for example is at most 0.2 
times the channel resistance. The on-state losses of a silicon component 4 
with a maximum reverse voltage of 50 V are, for example, significantly 
lower than in the case of a silicon component 4 which is designed for a 
reverse voltage of 600 V. Since, owing to the high breakdown strength of 
the semiconductor of the semiconductor configuration 5, the geometrical 
dimensions of the first semiconductor region 6 can be set to be distinctly 
smaller compared with silicon for the same reverse voltage, the drift 
resistance in the semiconductor configuration 5 can also be kept small. 
Due to the combination of the low-voltage silicon component 4 with the 
semiconductor configuration 5 having a high blocking capability, the 
electronic device consequently has only low on-state losses even at high 
reverse voltages of more than 500 V. 
For given semiconductor materials, the blocking capability of the p-n 
junction 7 of the semiconductor configuration 5 is adapted by the 
geometrical dimensions and the dopings of the semiconductor regions 6 and 
8 to the predetermined maximum operating reverse voltage U.sub.max. For 
predetermined dopings, the dimensions are chosen to be larger for larger 
maximum reverse voltages U.sub.max. For predetermined dimensions, the 
doping of the first semiconductor region 6 at least in the channel region 
9 is chosen to be lower, the greater the desired maximum reverse voltage 
U.sub.max is. Typical values for the n-type doping of the first 
semiconductor region 6, when a silicon carbide of the 4H polytype is used 
as the semiconductor material, are n=1.multidot.1016 cm.sup.-3 for a 
maximum reverse voltage U.sub.max =600 V present at the p-n junction 7, 
n=8.multidot.1015 cm.sup.-3 for U.sub.max =1200 V and n=5.multidot.1015 
cm.sup.-3 for U.sub.max =1800 V. On account of the high breakdown strength 
of the semiconductor material of the semiconductor configuration 5, the 
blocking capability of the depletion zone 70 of the p-n junction 7 is very 
much higher than it would be in silicon. Consequently, the absolute extent 
of the semiconductor regions 6 and 8 can also, preferably, be chosen to be 
small. In the case of the semiconductor material silicon carbide (SiC), 
for example, it is possible to choose dimensions which are smaller than in 
silicon by a factor of 10. The consequence of this is a bulk resistance 
which is reduced by the same factor of 10 and thus correspondingly lower 
on-state losses on the semiconductor configuration 5. 
Referring now to FIGS. 2 to 5, there are shown various advantageous 
embodiments of a semiconductor configuration that can be utilized as the 
semiconductor configuration 5 in the electronic device according to FIG. 
1. 
Referring first to FIG. 2, there is shown in cross-section the first 
semiconductor region 6 formed by a substrate 64 of a first conductivity 
type (n-conductivity in the example of the figure) and a semiconductor 
layer 63 of the same conductivity type as the substrate 64. The 
semiconductor layer is preferably epitaxially grown on the substrate 64. 
The semiconductor layer 63 is preferably more weakly doped (n.sup.- 
-doped) than the substrate 64 (n-doped). That surface of the semiconductor 
layer 63 which is remote from the substrate 64 forms a first surface 61 of 
the first semiconductor region 6. That surface of the substrate 64 which 
is remote from the semiconductor layer 63 forms a second surface 62 of the 
first semiconductor region 6. 
A plurality of further, mutually spaced-apart semiconductor regions 8A, 8B, 
8C, 8D, 8E, 8F and 8G are disposed on the first surface 61 of the first 
semiconductor region 6, and are in each case of the opposite conductivity 
type (of the p conductivity type in the example of the figure) as compared 
to the first conductivity type. The further semiconductor regions are 
preferably fabricated by ion implantation into the semiconductor layer 63. 
The semiconductor regions 8A to 8G (p.sup.+ -type regions) are preferably 
doped essentially identically with identical doping depth profiles. The 
associated p-n junctions which are formed by the semiconductor layer 63 
and a respective one of the further, oppositely doped semiconductor 
regions 8A to 8G are correspondingly designated by 7A to 7G. Preferably, 
the further semiconductor regions 8A to 8G are each doped more heavily 
(p.sup.+) than the semiconductor layer 63. Each of the further 
semiconductor regions 8A to 8G carries a respective electrode 18A, 18B, 
18C, 18D, 18E, 18F, and 18G on its surface. The electrodes 18A to 18G are 
electrically connected to one another and to the third terminal 5C of the 
semiconductor configuration 5. Formed between each pair of semiconductor 
regions 8A to 8G in the semiconductor layer 63 is a respective channel 
region, running essentially vertically with respect to the first surface 
61 and reaching up to this first surface 61: 9A (between the semiconductor 
regions 8A and 8B), 9B (between the semiconductor regions 8B and 8C), 9C 
(between the semiconductor regions 8C and 8D), 9D (between the 
semiconductor regions 8D and 8E), 9E (between the semiconductor regions 8E 
and 8F), and 9F (between the semiconductor regions 8F and 8G). An 
electrode 19A and 19B and 19C and 19D and 19E and 19F is respectively 
assigned to each of the channel regions 9A to 9F for the purpose of 
electrically contacting on the first surface 61 of the semiconductor layer 
63. All the electrodes 19A to 19F are electrically connected to the first 
terminal 5A of the semiconductor configuration 5. The electrodes 18A to 
18G, on the one hand, and the electrodes 19A to 19F, on the other hand, 
are electrically insulated from one another by a non-illustrated 
dielectric and can each be formed by a metal or else, in particular in the 
case of silicon carbide as semiconductor for the semiconductor 
configuration 5, by polysilicon. 
A large-area electrode 11 is advantageously arranged on the second surface 
62 of the first semiconductor region 6 on the rear side of the substrate 
64 and is electrically connected to the second terminal 5B of the 
semiconductor configuration 5. 
In the on-state mode, an electric current flows between the two terminals 
5A and 5B through the channel regions 9A to 9F, the semiconductor layer 63 
and the substrate 64 in a current direction which is essentially vertical 
with reference to the surfaces 61 and 62. This embodiment of the 
semiconductor configuration 5 according to FIG. 2 can therefore be 
compared with a vertical junction field-effect transistor (JFET). 
The distances between mutually adjacent semiconductor regions 8A and 8B or 
8B and 8C, etc. determine the channel width of the channel regions 9A to 
9F. These distances are preferably all smaller than the widths (extents) 
of the depletion zones of the p-n junctions 7A to 7G given a maximum 
operating reverse voltage U.sub.max between the terminals 5B and 5C. As a 
result, in the zero-current case (off-state mode), the individual 
depletion zones of the p-n junctions 7A to 7G overlap to form a common 
depletion zone 70, which preferably covers all the channel regions 9A to 
9F and is extended into the semiconductor layer 63. The smaller the 
distances are between each two neighboring semiconductor regions 8A to 8G 
at a predetermined maximum operating reverse voltage U.sub.max, the more 
planar the common depletion zone 70 becomes, with the result that the 
blocking capability is not significantly influenced by the "island 
structure" of the semiconductor regions 8A to 8G (p.sup.+ -type regions) 
and the curved profile thereof. The distances between the semiconductor 
regions 8A to 8G are preferably essentially equal to a fixed distance d. 
The distance d or the distances between the semiconductor regions 8A to 8G 
are generally chosen to be between about 5 .mu.m and about 20 .mu.m. The 
dimensioning of the distances or of the distance d between the 
semiconductor regions 8A to 8G is dependent, in particular, on the 
breakdown voltage of the silicon component 4 that is chosen and is not 
illustrated in FIG. 2. The absolute value of the difference between the 
electrical potential at the electrodes 18A to 18G and the electrical 
potential at the terminal 2 should be less than, and preferably distinctly 
less than, the breakdown voltage of the silicon component 4, in order to 
avoid destruction of the silicon component 4. 
The semiconductor regions 8A to 8G may be individual regions (islands) 
which are separated from one another, or else spaced-apart partial regions 
of a contiguous region. The thickness of the semiconductor layer 63 is, of 
course, chosen likewise to be sufficiently large for the maximum reverse 
voltage U.sub.max. 
FIG. 3 shows a plan view of the first surface 61 of the first semiconductor 
region 6 of a semiconductor configuration 5 according to FIG. 2 with 
electrodes 18A to 18E, which are connected together like a comb via a 
conductor strip 16, and electrodes 19A to 19D, which are connected 
together like a comb via a conductor strip 15. The electrodes 19A to 19D 
project into the gaps between the electrodes 18A to 18E. The electrode 
structure that intermeshes similarly to two combs can be produced with a 
single-layer metallization. The semiconductor regions 8A to 8G situated 
under the electrodes 18A to 18G are then preferably of insular design. 
FIG. 4 illustrates a development of the semiconductor configuration 5 
according to FIG. 2. The semiconductor layer 63 (n.sup.-) is here arranged 
via a buffer layer 66 on a oppositely doped (p.sup.+) substrate 65. In 
general, the buffer layer 66 is likewise formed from a semiconductor with 
a breakdown field strength of at least 10.sup.6 V/cm. In the illustrated 
embodiment, the buffer layer 66 is of the same conductivity type (n) as 
the semiconductor layer 63 and is preferably doped more highly (n.sup.+) 
than the semiconductor layer 63. This is particularly in a realization of 
a punch-through type, in which the space charge zone 70 punches through to 
the buffer layer 66. The buffer layer 66 and the semiconductor layer 63 
together form the first semiconductor region 6 of the semiconductor 
configuration 5. In an embodiment that is not illustrated, the buffer 
layer 66 is, in contrast, of the same conductivity type (p) as the 
substrate 65. 
Thus, in the embodiment according to FIG. 4, an additional p-n junction is 
introduced into the semiconductor configuration 5 and is connected between 
the terminals 5A and 5C. In the electronic device according to FIG. 1, 
this additional p-n junction is electrically connected in series with the 
silicon component 4 and the channel regions 9A to 9F (9 in FIG. 1) between 
the two terminals 2 and 3. This embodiment of FIG. 4 is comparable with an 
IGBT (insulated gate bipolar transistor). 
In the embodiment of the electronic device according to FIG. 5, a 
semiconductor configuration 5 constructed as in FIG. 2 and the silicon 
component 4 are integrated to form a hybrid component. An insulation layer 
12 made of a dielectric material, for example silicon dioxide, is applied 
over the electrodes 18A to 18G assigned to the semiconductor regions 8A to 
8G of the semiconductor configuration 5. The insulation layer 12 is 
provided with contact holes in regions above the channel regions 9A to 9F. 
An electrode layer 19 made of an electrically conductive material is 
applied to the insulation layer 12. Those parts of the electrode layer 19 
which make contact with the channel regions 9A to 9F through the contact 
holes in the insulation layer 12 form the individual electrodes 19A to 
19F. Such a structure can be produced using buried-gate technology. The 
silicon component 4 is bonded to the electrode layer 19 via a bonding 
layer 13. For the connection (bonding), it is possible to use, in 
particular, a soldering technique (chip-on-chip soldering), a bonding wire 
connection technique or else direct wafer bonding. The silicon component 4 
that is provided is, for example, a vertical MOSFET using DDMOS technology 
which is known per se and therefore illustrated only diagrammatically, 
with a silicon wafer 46, a plurality of base regions 41 diffused into the 
silicon wafer 46, source regions 42 diffused into the base regions 41, at 
least one gate electrode 44, which is assigned via an insulator region 43 
in each case to at least one channel 40 in the base region 41, and source 
electrodes 45, via which the source regions 42 and the base regions 41 are 
electrically short-circuited. 
FIG. 6 illustrates a circuit diagram of an embodiment of the electronic 
device that can be constructed in a discrete embodiment. A silicon MOSFET, 
for example a commercially available low-voltage power MOSFET, is provided 
as the silicon component 4. The gate of the MOSFET forms the control 
terminal 4C, the source forms the first terminal 4A of the silicon 
component 4. The first terminal 4A is connected to the first terminal 2 of 
the electronic device. The drain forms the second terminal 4B of the 
silicon component 4. The semiconductor configuration 5 is represented by 
the circuit symbol of a JFET and can be designed as in FIG. 2, for 
example. The source of the JFET forms the first terminal 5A of the 
semiconductor configuration 5 and is thus short-circuited with the drain 
of the silicon MOSFET. The drain of the JFET forms the second terminal 5B 
of the semiconductor configuration 5 and is electrically connected to the 
second terminal 3 of the electronic device. The gate of the JFET forms the 
third terminal 5C of the semiconductor configuration 5 and is electrically 
short-circuited with the first terminal 2 of the electronic device and the 
source of the silicon MOSFET. Such an electronic device, which may be 
referred to as a hybrid power MOSFET, enables, in particular, reverse 
voltages of up to 5000 V and rated currents (forward currents) of between 
5 A and 500 A to be achieved, if silicon carbide (SiC) is used as 
semiconductor material for the semiconductor configuration 5. 
In yet a further embodiment of the novel electronic device it is possible 
to combine a semiconductor configuration 5 from the IGBT-like hybrid (cf. 
FIG. 4) based on silicon carbide (SiC) with a silicon MOSFET. In that case 
it is possible to achieve reverse voltages of up to 10,000 V and rated 
currents of between 100 A and 1000 A. 
In general, the electronic device is connected as electronic switch into an 
electrical line or a line branch of an electrical voltage network, for the 
purpose of switching on and off an electric current for an electrical 
load. 
If the silicon power MOSFET is replaced by a so-called smart power silicon 
MOSFET or a corresponding intelligent silicon component 4 for switching, 
then the electronic device can be equipped not only with switching 
functions but also with protection functions, such as e.g. overvoltage 
protection or overcurrent disconnection.