CN109920840B

CN109920840B - L-shaped SiO2Composite RC-LIGBT device with isolation layer

Info

Publication number: CN109920840B
Application number: CN201910213984.4A
Authority: CN
Inventors: 陈伟中; 黄垚; 李顺; 黄义; 贺利军
Original assignee: Chongqing University of Post and Telecommunications
Current assignee: Chongqing University of Post and Telecommunications
Priority date: 2019-03-20
Filing date: 2019-03-20
Publication date: 2022-02-11
Anticipated expiration: 2039-03-20
Also published as: CN109920840A

Abstract

The invention relates to a method for preparing L-shaped SiO₂The isolation layer is a composite RC-LIGBT device made of L-type SiO₂The isolation layer is a boundary and is divided into an LDMOS region and an LIGBT region, and the isolation layer has the following advantages in the working process: (1) the peak of the electric field of the device is reduced, and the advanced breakdown on the surface of the device is avoided, so that the breakdown voltage is improved; (2) when the device is in a stable transition state in the conversion process of the three modes during forward conduction, the current sudden change condition is avoided; (3) when the LDMOS is reversely conducted, the LDMOS region independently works, the N-Collector provides electrons, and the P-body directly injects holes into the drift region under the reverse bias of the emitter to endow the device with the conducting capability in a reverse bipolar mode. Through simulation verification under the same parameter condition, the breakdown voltage of the composite RC-LIGBT device is improved to 206.05V; the circuit has no Snapback phenomenon and also has reverse conduction capability.

Description

L-shaped SiO2Composite RC-LIGBT device with isolation layer

Technical Field

The invention belongs to the field of semiconductor power devices, and particularly relates to a semiconductor power device with L-shaped SiO₂And the isolation layer is a composite RC-LIGBT device.

Background

The LIGBT (lateral Insulated Gate Bipolar transistor) based on the SOI material has the advantages of good insulating property, small parasitic capacitance, lower leakage current, high integration level and the like, and the manufacturing process is compatible with the SOI-CMOS process and is easy to realize. Therefore, it will become one of the core components of the smart power integrated circuit, and is widely applied in the fields of household electrical appliances, environmental protection automobiles, industrial production and the like, and is a semiconductor power device with great potential in the future market. However, the LIGBT structure is equivalent to two back-to-back diodes when conducting reversely, and a PN junction formed by a P-Collector and an N-buffer at a Collector is always in a reverse bias state, so the LIGBT does not have reverse conducting capability. To circumvent this disadvantage, a free Wheeling diode fwd (free Wheeling diode) is usually connected in anti-parallel in typical inverter circuit applications of LIGBT for protection. With the advance of technology, the traditional RC-LIGBT device (Re) is developed laterreverse-Conducting laterally-Insulated Gate Bipolar Transistor), a freewheeling diode is integrated into an RC-LIGBT, and the technical method is as follows: the N-Collector is used for replacing the P-Collector of the Collector part, so that the N-Collector can inject electrons into the drift region when the drift region is conducted in the reverse direction, the drift region has reverse conduction capability, and the structure of the N-Collector arranged at the Collector is shown in figure 3. The technology improves the integration level of the chip, greatly reduces the area of the chip, reduces the parasitic capacitance and improves the stability of the device. The working mismatch between the LIGBT chip and the diode chip caused by the temperature difference is eliminated, and the reliability of the device is improved. However, conventional RC-LIGBT devices also have some inherent disadvantages: firstly because of the introduction of the N-Collector, due to the heavily doped P-Collector for the N-emitter⁺The electrons flowing out are a high barrier, which blocks the electrons from flowing to the metal collector. Electrons flow to the N-Collector part of the Collector electrode through the N-buffer first, and a potential difference V is generated between the N-buffer and the P-Collector when the electrons flow_PN. This potential difference becomes critical for the switching of the conduction mode, at V_PNBelow 0.8V only from N⁺The injected electrons participate in the conduction, and the RC-LIGBT is in a unipolar type conduction mode. While V is the value when the electron current flowing in the N-buffer increases_PNThe voltage exceeds 0.8V, at the moment, a PN junction between the N-buffer and the P-Collector is opened, the P-Collector injects holes into the drift region, at the moment, the conduction mode conversion is realized, the Snapback phenomenon is caused in the process, the current and voltage sudden change occurs on an output curve, and the dynamic characteristic of the device is greatly influenced. This phenomenon can also hinder full turn-on of other devices in the circuitry when RC-LIGBTs are used in parallel at low temperatures.

Disclosure of Invention

In view of the above, the present invention is directed to providing a composition having L-type SiO₂And the isolation layer is a composite RC-LIGBT device.

In order to achieve the above purpose, the invention provides the following technical scheme:

l-shaped SiO₂Composition of isolating layerA composite RC-LIGBT device comprising L-type SiO₂The device comprises an isolation layer, an LDMOS region, an LIGBT region, a collector and a shared active region.

Preferably, the composite RC-LIGBT device is formed by the L-type SiO₂The isolation layer is divided to form an LDMOS region in the upper left region and an LIGBT region in the lower right region.

Preferably, the shared active region comprises a source electrode, a gate oxide layer, a medium isolation layer and a substrate, wherein the gate oxide layer is positioned between the source electrode and the L-shaped SiO₂Between the horizontal ends of the isolation layer, the gate oxide completely surrounds the gate.

Preferably, the LDMOS region comprises a P-body heavily doped P arranged from left to right⁺The semiconductor device comprises a region, a lightly doped P region, a rectangular N-drift region, an arc N-buffer region and an N-Collector region; wherein the P-body is heavily doped with P⁺The region is connected to the source.

Preferably, the LDMOS region further comprises an N + electron emitter, the left side of the N + electron emitter is contacted with the source electrode, and the upper side of the N + electron emitter is heavily doped with P of the P-body⁺The area contacts, the right side contacts with the lightly doped P area, and the lower side contacts with the gate oxide layer.

Preferably, the LIGBT region is provided with P-body heavy doping P from left to right in sequence in the horizontal direction⁺A region, a lightly doped P region, and an L-type N-drift region, wherein the P-body is heavily doped with P⁺The region is connected to the source.

Preferably, the LIGBT region further comprises an N + electron emitter, the left side of the N + electron emitter is in contact with the source electrode, the upper side is in contact with the gate oxide layer, the right side is in contact with the lightly doped P region, and the lower side is in contact with the heavily doped P of the P-body⁺The regions are in contact.

Preferably, the LIGBT region further comprises an N-buffer region (14) arranged above the vertical end of the L-type N-drift region and a P-Collector region positioned above the N-buffer region.

Preferably, the lower part of the Collector electrode is sequentially connected with the N-Collector region and the L-type SiO from left to right₂The vertical end of the isolation layer contacts the P-Collector region.

The invention has the beneficial effects that: the invention disclosesOpen a kind of film with L-shaped SiO₂Composite RC-LIGBT device of isolation layer, device is by L type SiO₂The isolation layer is divided into the LDMOS region and the LIGBT region, and the LDMOS device has the following advantages:

(1) when breakdown voltage resistance is realized, the L-shaped SiO2 isolation layer is introduced to guide the surface electric field of the transistor device into the device body, so that the in-body electric field of the device is greatly enhanced, and the electric field in the device body is more uniform in distribution and higher in strength; meanwhile, the local electric field peak of the device can be reduced, the situation that the surface of the device is punctured in advance when avalanche breakdown is not achieved before a drift region is exhausted like a traditional RC-LIGBT device is avoided, and therefore the breakdown voltage of the composite RC-LIGBT device is improved.

(2) When conducting in the forward direction, the conducting process of the composite RC-LIGBT device is divided into three steps:

the first step is as follows: in a unipolar conduction mode of the LDMOS region, electrons are injected into an L-type N-drift region of the LDMOS from an N + emitter of the LDMOS region and flow out of an N-Collector region after flowing through the N-buffer region, at the moment, the electrons injected by the N + electron emitter in the LIGBT region are blocked by a hole barrier formed by heavy doping of a P-Collector region, a PN junction formed by the P-Collector region and the N-buffer region of the LIGBT region is in a cut-off state, and no current flows;

the second step is that: with the voltage increase of the LDMOS region and the Collector of the LIGBT region, the P-Collector region of the LIGBT region starts to inject holes into the rectangular N-drift region of the LIGBT region, and a LIGBT + LDMOS mixed conduction mode is formed;

the third step: because the LIGBT region adopts a bipolar conductive mode, the current exponentially increases along with the voltage, and the voltage of the collector continuously increases, the composite RC-LIGBT device is mainly conductive in the bipolar conductive mode of the LIGBT region;

therefore, the whole conducting process of the forward conduction is transited from the LDMOS region as a main part to the LDMOS + LIGBT mixed conducting mode, the bipolar conducting mode of the LIGBT region is continuously formed as a main part, the device is in a stable transition state in the conversion process, and the current sudden change condition is avoided, so that the forward conduction process of the composite RC-LIGBT device does not have the Snapback phenomenon.

(3) When the LDMOS is reversely conducted, the LDMOS region can be equivalent to a PN junction formed by a P-body lightly doped region and a rectangular N-drift region, the PN junction is forward biased, and the N-collector region belongs to a low potential barrier relative to electrons and allows electron current to flow through; the LIGBT region can be equivalent to a back-to-back diode composed of a light doping region, an L-type N-drift region and a P-collector, namely a PNP structure, wherein a PN junction formed by the light doping region and the N-drift region is forward biased, and a PN junction formed by the L-type N-drift region and the P-collector region is reverse biased, so that electron current is not allowed to flow; therefore, the composite RC-LIGBT device has good independence on reverse operation.

Drawings

In order to make the object, technical scheme and beneficial effect of the invention more clear, the invention provides the following drawings for explanation:

FIG. 1 is a schematic structural diagram of a conventional LDMOS device;

FIG. 2 is a schematic diagram of a conventional LIGBT device;

FIG. 3 is a schematic structural diagram of a conventional RC-LIGBT device;

FIG. 4 shows a process for preparing L-shaped SiO₂The structure schematic diagram of the composite RC-LIGBT device of the isolation layer, namely the novel RC-LIGBT device;

FIG. 5 shows the drift region concentrations of the conventional LDMOS, the conventional LIGBT, the conventional RC-LIGBT and the novel RC-LIGBT device of the present invention at breakdown are 1 × 10¹⁴And 2X 10¹⁴A lateral comparison graph of breakdown voltage in the lower avalanche breakdown state;

FIG. 6 shows the concentration of the conventional LDMOS, the conventional LIGBT, the conventional RC-LIGBT and the novel RC-LIGBT device of the present invention in the drift region of 1 × 10¹⁴Potential distribution lateral comparison diagram under the avalanche breakdown state;

FIG. 7 shows the drift region concentrations of the conventional LDMOS, the conventional LIGBT, the conventional RC-LIGBT and the novel RC-LIGBT device of the present invention at breakdown are 1 × 10¹⁴Comparing the time-domain three-dimensional electric field intensity transversely;

FIG. 8 shows the drift region concentrations of the conventional LDMOS, the conventional LIGBT, the conventional RC-LIGBT and the novel RC-LIGBT device of the present invention at breakdown are 1 × 10¹⁴When the coordinate Y is equal to 0, the one-dimensional electric field intensity is compared with the graph transversely;

FIG. 9 shows the drift region concentrations of the conventional LDMOS, the conventional LIGBT, the conventional RC-LIGBT and the novel RC-LIGBT device of the present invention at breakdown are 1 × 10¹⁴When the coordinate Y is 0.5, comparing the one-dimensional electric field intensity transversely;

FIG. 10 is a lateral comparison of output characteristic curves for a conventional LDMOS, a conventional LIGBT, a conventional RC-LIGBT and the novel RC-LIGBT device of the present invention in a forward conduction condition;

FIG. 11 is a diagram of a lateral comparison of conduction patterns of conventional RC-LIGBT and the novel RC-LIGBT device of the present invention at different collector voltages in a MEDICI simulation environment when conducting in the forward direction;

fig. 12 is a longitudinal comparison graph of output characteristic curves of the novel RC-LIGBT device when the area Ratio of the LDMOS region to the LIGBT region of the novel RC-LIGBT device of the present invention is S1: S2 is 1:3, 1:2, 1:1, 2:1, respectively, in forward conduction;

fig. 13 is a longitudinal comparison diagram of forward conducting current distribution of the novel RC-LIGBT device of the present invention when the Ratio of the areas of the LDMOS area and the LIGBT area is 1:3, 1:2, 1:1, 2:1, S1: 2 is 1:3, 1:2, 1:1, 2:1, respectively, in the media simulation environment;

FIG. 14 is a longitudinal comparison of reverse current versus emitter voltage curves for a conventional LDMOS, a conventional LIGBT, a conventional RC-LIGBT and the novel RC-LIGBT device of the present invention when turned on in the reverse direction;

fig. 15 is a longitudinal comparison graph of relationship curves between reverse current and emitter voltage under conditions that the Ratio of the areas of the LDMOS region and the LIGBT region of the novel RC-LIGBT device of the present invention is S1: S2 is 1:3, 1:2, 1:1, 2:1, respectively;

fig. 16 is a longitudinal comparison diagram of reverse current distribution of the novel RC-LIGBT device of the present invention under the conditions that the Ratio of the areas of the LDMOS region and the LIGBT region, Ratio of S1: S2, is 1:3, 1:2, 1:1, 2:1, respectively, when the device is turned on in the reverse direction in the medicine simulation environment;

fig. 17 is a longitudinal comparison graph of the turn-off time and the collector current of the novel RC-LIGBT device of the present invention at the Ratio of the areas of the LDMOS region and the LIGBT region, Ratio of S1: S2, 1:1.5, 1:1, 1.5:1, 2:1, 2.5:1, respectively, when turned off;

wherein1 is an N + electron emitter, 2 is a grid, 3 is a gate oxide, 4 is a source, 5 is a lightly doped P region, 6 is a rectangular N-drift region, 7 is a Collector, 8 is a P-Collector region, 9 is an arc N-buffer region, 10 is a dielectric isolation layer, 11 is a substrate, 12 is an N-Collector region, and 13 is a heavily doped P of a P-body⁺Region 14 is N-buffer region, 15 is L-type N-drift region, and 16 is L-type SiO₂The isolation layer, S1 is LDMOS region, S2 is LIGBT region.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention in a schematic way, and the features in the following embodiments and examples may be combined with each other without conflict.

Wherein the showings are for the purpose of illustrating the invention only and not for the purpose of limiting the same, and in which there is shown by way of illustration only and not in the drawings in which there is no intention to limit the invention thereto; to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there is an orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", etc., based on the orientation or positional relationship shown in the drawings, it is only for convenience of description and simplification of description, but it is not an indication or suggestion that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes, and are not to be construed as limiting the present invention, and the specific meaning of the terms may be understood by those skilled in the art according to specific situations.

L-shaped SiO₂The composite RC-LIGBT device with the isolation layer has a structure schematic diagram shown in FIG. 4, and comprises an N + electron emitter 1, a gate 2, a gate oxide layer 3, a source 4, a lightly doped P region 5, a rectangular N-drift region 6, a Collector 7, a P-Collector region 8, an arc N-buffer region 9, a dielectric isolation layer 10, a substrate 11, an N-Collector region 12, and a P-body heavily doped P⁺Region 13, N-buffer region 14, L-type N-drift region 15, L-type SiO₂An isolation layer 16.

In the presence of L-type SiO₂L-type SiO in novel composite RC-LIGBT device of isolation layer₂The isolation layer divides the device into an LDMOS region S1 in the upper left region and a LIGBT region S2 in the lower right region, wherein the LDMOS region and the LIGBT region further have a shared active region, and the shared active region comprises a source 4, a gate 2, a gate oxide layer 3, a dielectric isolation layer 10 and a substrate 11.

The LDMOS region in the novel composite RC-LIGBT device comprises a heavily doped P with a P-body arranged from left to right⁺A region 13, a lightly doped P region 5, a rectangular N-drift region 6, an arc N-buffer region 9 and an N-Collector region 12, wherein the P-body is heavily doped with P⁺Region 13 is connected to source 4; and further comprises an N + electron emitter 1, the left side of which is in contact with the source 4 and the upper side of which is heavily doped P with P-body⁺The region contacts, the right side of the LDMOS is in contact with the lightly doped P region, and the lower side of the LDMOS is in contact with the gate oxide layer, wherein the N-buffer region in the LDMOS region is mainly used as a field stop layer of the LDMOS region, so that the depletion layer is prevented from being directly communicated with the N-collector region after being expanded, and the voltage resistance of the device is improved.

The LIGBT in the device is provided with P-body heavy doping P from left to right in sequence in the horizontal direction⁺Region 13, lightly doped P region 5, and L-type N-drift region 15, wherein P-body is heavily doped with P⁺The region is connected with the source electrode; the N + electron emitter 1 is contacted with the source electrode on the left side, the gate oxide on the upper side, the lightly doped P region on the right side and the heavily doped P of the P-body on the lower side⁺A region contact; the LIGBT region also comprises an N-buffer region 14 arranged above the vertical end of the L-shaped drift region and an N-b regionAnd a P-Collector region 8 above the buffer region, wherein the N-buffer region can independently adjust the conduction voltage drop of the LIGBT region and the hole emission efficiency at the P-Collector region on the premise of not influencing the performance of the LDMOS region.

The lower part of a Collector 7 in the composite RC-LIGBT device is sequentially connected with an N-Collector region and an L-type SiO from left to right₂The isolation layer and the upper part of the P-Collector region.

In the presence of L-type SiO₂The L-shaped drift region in the novel composite RC-LIGBT device of the isolation layer is formed by an epitaxial growth method, and forms an SOI structure, namely a silicon-on-insulator structure together with the substrate and the dielectric isolation layer.

A specific material is provided with L-type SiO₂And placing the composite RC-LIGBT device of the isolation layer into a coordinate system, wherein the positions of the corresponding parts are as follows:

in the common active region, source 4: the ordinate is 0-25 μm, and the abscissa is 0-0.3 μm; a grid electrode 2: the abscissa is 0.5-2 μm, and the ordinate is 19.2-20 μm; gate oxide layer 3: the ordinate is 19-20.2 μm, the abscissa is 0.3-2.2 μm, and the thickness of the gate oxide layer 3 is 0.2 μm; dielectric isolation layer 10: the abscissa is 0-17 μm, and the ordinate is 25-25.375 μm; substrate 11: the abscissa is 0 to 17 μm and the ordinate is 25.375 to 27.375 μm.

Heavily doped P of P-body in LDMOS region⁺Zone 13: the ordinate is 0-17 μm, and the abscissa is 0.3-1.2 μm; n + electron emitter 1: the abscissa is 0.3-1.2 μm, and the ordinate is 17-19 μm; lightly doped P region 5: the ordinate is 0-19 μm, and the abscissa is 1.2-1.8 μm; rectangular N-drift region 6: the ordinate is 0-19 μm, and the abscissa is 1.8-12.5 μm; arc N-buffer 9: the abscissa is 10-12.5 μm and the ordinate is 0-4 μm; n-collector region 12: the abscissa is 11-12.5. mu.m, and the ordinate is 0-2 μm.

L-type SiO₂Isolation layer 16: the ordinate of the horizontal part is 19-20.2 μm, the abscissa is 2.2-13 μm, the abscissa of the vertical part is 12.5-13 μm, and the ordinate is 0-19 μm.

In the LIGBT region, N + electron emitter 1: the abscissa is 0.3-1.2 μm, and the ordinate is 20.2-22.2 μm; heavily doped P of P-body⁺Zone 13: abscissa of 0.3 ℃1.2 mu m, and the ordinate is 22.2-25 mu m; lightly doped P region 5: the abscissa is 1.2-1.8 μm, and the ordinate is 20.2-25 μm; l-type N-drift region 15: the horizontal part has the abscissa of 1.8-17 μm and the ordinate of 20.2-25 μm, and the vertical part has the abscissa of 13-17 μm and the ordinate of 4-20.2 μm; p-collector region 8: the abscissa is 13-17 μm and the ordinate is 0-2 μm; n-buffer zone 14: the abscissa is 13 to 17 μm and the ordinate is 2 to 4 μm.

Collector electrode 7: the abscissa is 11.5 to 17 μm and the ordinate is-0.2 to 0 μm.

The invention provides a method for preparing L-shaped SiO₂The structure of the composite RC-LIGBT new structure of the isolation layer is shown in figure 4. The structure comprises an emitter, a grid, an N-drift region of LDMOS, and N of LIGBT arranged from left to right^-Drift region, L-type SiO₂Isolation layer, trench type SiO₂Buried layer, collector. The Collector comprises a buffer layer N-buffer of the LDMOS region arranged on the left and right, and a vertical P Collector P-Collector and an N-buffer region which surround the N-Collector region and the LIGBT region and have hole emission capability.

The RC-LIGBT mechanism provided by the invention is as follows:

the first step is as follows: in a unipolar conduction mode of the LDMOS region, electrons are injected into a drift region of the LDMOS from an N + emitter of the LDMOS region, flow through the N-buffer region and then flow out of the N-Collector region, at the moment, the electrons injected from the N + electron emitter in the LIGBT region are blocked by a hole barrier formed by heavy doping of the P-Collector region, a PN junction formed by the P-Collector region and the N-buffer region of the LIGBT region is in a cut-off state, and no current exists;

the second step is that: with the voltage increase of the LDMOS region and the Collector of the LIGBT region, the P-Collector region of the LIGBT region starts to inject holes into the drift region of the LIGBT region, and a LIGBT + LDMOS mixed conduction mode is formed;

(3) When the LDMOS is reversely conducted, the LDMOS region can be equivalent to a PN junction formed by a P-body lightly doped P region and a drift region, the PN junction is forward biased, and the N-collector region belongs to a low potential barrier relative to electrons and allows electron current to flow through; the LIGBT region can be equivalent to a back-to-back diode composed of a P-body lightly doped P region, an N-drift region and a P-collector region, namely a PNP structure, wherein a PN junction formed by the P-body lightly doped P region and the N-drift region is forward biased, and a PN junction composed of the N-drift region and the P-collector is reverse biased, so that an electron current is not allowed to flow; therefore, the composite RC-LIGBT device has good independence on reverse operation.

By means of the simulation software, the simulation comparison of the provided traditional LDMOS device shown in FIG. 1, the traditional LIGBT device shown in FIG. 2, the traditional RC-LIGBT device shown in FIG. 3 and the novel RC-LIGBT device provided by the invention and shown in FIG. 4 is carried out, and the simulation parameters of four structures are consistent in the simulation process, wherein N is the same as N^-The total thickness of the drift region is 25 μm, the service life of the carrier is 10 μ s, the ambient temperature is 300K, the length is 17 μm, and the doping concentration N_dAnd the concentration of the buffer layer N-buffer is adjustable.

Fig. 5 shows the concentration in the drift region of 1 × 10 at room temperature when T is 300K¹⁴、2×10¹⁴Is broken downThe concentration Nd of the traditional LDMOS, the traditional LIGBT, the traditional RC-LIGBT and the novel RC-LIGBT devices in a drift region is 1 multiplied by 10 respectively¹⁴、2× 10¹⁴The breakdown voltage in reverse breakdown in the avalanche breakdown state is compared with that in the avalanche breakdown state. The graph of the data result obtained by the medicine simulation and drawn by the Origin tool is shown in fig. 5, and it can be seen that: at 1X 10¹⁴Doping concentration of the drift region of (a): the breakdown voltage of the novel RC-LIGBT is far greater than that of a traditional RC-LIGBT structure, and under the same structure parameters, the breakdown voltage of the novel RC-LIGBT is 206.05V, which is 107% higher than that of 99.491V of the traditional RC-LIGBT; the breakdown voltage of 55.103V is improved by 273.93% compared with the traditional LIGBT, and the breakdown voltage of 136.85V is improved by 50% compared with the traditional LDMOS. At the same time, at 2 × 10¹⁴Under the doping concentration of the drift region, the breakdown voltage of the novel RC-LIGBT is still far greater than that of a traditional RC-LIGBT structure, and under the same structure parameters, the breakdown voltage of the novel RC-LIGBT is 154.803V, which is about 37% higher than that of 112.957V of the traditional RC-LIGBT. The breakdown voltage of 45.561V is improved by 240% compared with the conventional LIGBT, and the breakdown voltage of 112.933V is improved by about 37% compared with the conventional LDMOS. It can be seen that the doping concentration in the two drift regions is 1 × 10¹⁴、2×10¹⁴The breakdown voltage of the novel RC-LIGBT device is the largest.

FIG. 6 simulates the drift region concentration Nd of 1 × 10 in the conventional LDMOS, the conventional LIGBT, the conventional RC-LIGBT and the novel RC-LIGBT devices in breakdown¹⁴A potential comparison diagram in an avalanche breakdown state with 5V/Contour is formed between adjacent equipotential lines; it can be seen that the potential of the novel RC-LIGBT transistor is uniformly distributed in the whole transistor, the density of equipotential lines is far greater than that of other structures, and originally, the region with relatively dense potential below the source electrode in each traditional structure becomes sparse, because the internal L-shaped SiO₂The isolation layer guides the electric field into the body, so that the equipotential lines are dense, the breakdown voltage is higher than that of the traditional LDMOS, the traditional LIGBT and the traditional RC-LIGBT devices, and the introduction of the L-type SiO is illustrated₂The isolation layer also increases the electric field intensity inside the transistor and reduces the electric field intensity on the surface of the device.

FIG. 7 simulates the conventional LDMOS, the conventional LIGBT, the conventional RC-LIGBT and the novel LDMOS in the breakdown stateCompared with the three-dimensional electric field diagram of the RC-LIGBT device, it can be seen that in the traditional LDMOS, the traditional LIGBT and the traditional RC-LIGBT device, an electric field peak exists near the source, the electric field distribution is very uneven, and the local electric field is too large, which shows that at the position of the electric field peak of the device, breakdown occurs in advance before the punch-through breakdown occurs, namely when the drift region is not completely exhausted. Specifically, this peak electric field is 21.59285 × 10 in the conventional LDMOS device⁵V/μm, which is 10.93422 × 10 in the conventional LIGBT device⁵V/μm, which is 6.854723 × 10 in the conventional RC-LIGBT device⁵V/. mu.m. In addition, the difference between the three traditional structures is that the novel RC-LIGBT device is in L-type SiO₂The isolation layer changes the structure of the device and utilizes SiO with higher withstand voltage and high dielectric constant₂The medium carries out effective optimization on the problems of extremely uneven electric field distribution, overlarge surface electric field and the like in the traditional structure. From fig. 7, it can be seen that the electric field distribution is more uniform and no extra large electric field peak occurs inside the whole novel RC-LIGBT device, and the maximum electric field is only 2.694096 × 10⁵V/. mu.m. And comparing with the SiO of the buried layer₂It is obvious that the difference between the local electric field peak value and the internal electric field is less than 2.0 multiplied by 10⁵V/. mu.m. It can be seen from fig. 7 that this value is much higher than the difference value in the conventional LDMOS, the conventional LIGBT, and the conventional RC-LIGBT device, which means that the peak electric field difference is not large everywhere in the novel RC-LIGBT device, and in comparison, the novel RC-LIGBT device is not prone to early breakdown, and the depletion layer can be fully extended to the collector, so the novel RC-LIGBT device has a higher breakdown voltage.

FIG. 8 simulates the concentration Nd of 1 × 10 in the drift region of conventional LDMOS, conventional LIGBT, conventional RC-LIGBT and novel RC-LIGBT devices¹⁴Comparing the surface electric field in the avalanche breakdown state, it can be seen that the traditional LDMOS, the traditional LIGBT and the traditional RC-LIGBT devices have very high surface electric fields. According to the data of the MEDICI simulation result, the peak value of the surface electric field of the traditional LDMOS device appears at the position where X is 5.5 mu m and is 2.159285 multiplied by 10⁶V/mum; surface of conventional LIGBT deviceThe peak value of the electric field appears at 5.5 μm and is 1.093422 × 10⁶V/mum; the peak value of the surface electric field of the traditional RC-LIGBT device appears at X1 mu m and is 0.6854723 multiplied by 10⁶V/mum; in contrast, due to the introduction of L-type SiO in the structure of the novel RC-LIGBT device₂Isolating layer to reduce the electric field peak in drift region, whose surface electric field peak appears at X-9.875 μm and is only 0.2694096 × 10⁶V/mum, much smaller than the conventional structure. From the point of view, the surface electric field of the traditional LDMOS device is the largest, the traditional LIGBT device is the second, the traditional RC-LIGBT device is smaller, the peak value of the surface electric field of the novel RC-LIGBT device is the smallest under comparison, according to the Resurf principle, the surface electric field is reduced, the novel RC-LIGBT device introduced into the body has the highest breakdown voltage theoretically, the novel structure just utilizes the principle, and meanwhile, the simulation result proves the theory, so that the breakdown voltage of the novel RC-LIGBT device is greatly optimized.

FIG. 9 simulates the concentration Nd of 1 × 10 in the drift region of conventional LDMOS, conventional LIGBT, conventional RC-LIGBT and novel RC-LIGBT devices¹⁴When the voltage is zero, Y in the avalanche breakdown state is 0.5. It can be seen that the electric field of the new RC-LIGBT device is the largest at Y ═ 0.5 μm, and is also the most uniformly distributed. According to the simulation result data of MEDICI, the L-type SiO₂The introduction of the isolation layer optimizes the electric field of the device, so that two electric field peaks with small difference exist in the device body. As can be seen in FIG. 9, the novel RC-LIGBT device is at X compared to the conventional device₁The electric field peak at 9.875 μm is increased by about 4 times, e.max1-279084.6V/μm; at X₂1.80586 μm, e.max2 190308.7V/μm. Intuitively, the area of a closed graph formed by the electric field curve and the X axis can be used as a reference for comparing the electric field, so that the internal electric field of the traditional LDMOS device at the position of 0.5 mu m Y is lower than that of the novel RC-LIGBT device, but higher than that of the traditional LIGBT device, and the electric field of the traditional RC-LIGBT device is the lowest. The structure of the novel RC-LIGBT device is used for weakening the surface electric field and enhancing the internal electric field, so that the aim of improving the breakdown voltage is fulfilled; and this size is consistentThe sequence is also positively correlated with the obtained breakdown voltage magnitude sequence of the traditional LDMOS, the traditional LIGBT, the traditional RC-LIGBT and the novel RC-LIGBT device in the MEDICI simulation environment.

FIG. 10 shows the concentration Nd of 1 × 10 in the drift region of conventional LDMOS, conventional LIGBT, conventional RC-LIGBT and novel RC-LIGBT devices¹⁴Then, the output characteristic curves at the time of forward conduction processed by Origin are compared with each other. As shown in fig. 10, when the collector voltage is 0.6V, there is a significant slope difference between the conventional LDMOS, the conventional LIGBT, the conventional RC-LIGBT and the novel RC-LIGBT device, wherein the conventional LDMOS device is a unipolar conductive device, the collector N-collector of the conventional LDMOS device is a low barrier with respect to electrons, and the electrons flow out from the collector as carriers, so that a relatively large electron current is generated at the initial time when the bias voltage is applied to the collector; the collector of the traditional LIGBT device is only a part of the P-collector, a PN junction formed by the P-collector and the N-buffer exists on the collector, the PN junction is not started before the threshold voltage is reached, and no current is generated; in contrast, the collectors of the conventional RC-LIGBT and the novel RC-LIGBT devices are composed of an N-collector and a P-collector, and there is a conversion process from a unipolar conduction mode to a bipolar conduction mode from an electron current to an electron and hole current. According to the simulation result, the traditional LIGBT device directly enters a bipolar conduction mode when the traditional LIGBT device reaches the opening voltage of about 0.6V, so that the current of the traditional LIGBT device is the maximum under the same condition among the traditional LIGBT device, the traditional RC-LIGBT device and the novel RC-LIGBT device; the collectors of the traditional RC-LIGBT and the novel RC-LIGBT device have two parts, namely an N-Collector and a P-Collector, and for the traditional RC-LIGBT device, due to the introduction of the N-Collector, the heavily doped P-Collector is opposite to the N-Collector of the driven emitter⁺The outgoing electrons are a high potential barrier and block the electrons from flowing to the metal Collector, so that when the voltage of the Collector is 0.6V lower than the threshold of a PN junction between the N-buffer and the P-Collector, the electrons firstly flow to the N-Collector part of the Collector through the N-buffer, and only the electrons from the N-Collector part at the moment⁺The electrons of the electron emitter participate in conduction, as shown at point A, C, to place the RC-LIGBT device in a unipolar mode of conduction. As shown in fig. 10, as the collector voltage increases,the electron current flowing in the N-buffer increases, V_PNThe value exceeds 0.6V, at the moment, a PN junction between the N-buffer and the P-Collector is opened, the P-Collector injects holes into the drift region, at the moment, the conduction mode conversion is realized, and the conduction mode is converted from N⁺Participate in the conduction of electricity and from the P-collector, as shown at point B, D in the figure. The sudden current change of the conventional RC-LIGBT in this process causes Snapback phenomenon, and a very obvious voltage retrace appears as shown in fig. 10. In contrast, the novel RC-LIGBT device is introduced with L-type SiO₂The whole conducting process of the isolating layer is from LDMOS being the main mode to LDMOS + LIGBT mixed mode and then to LIGBT being the main mode, the conversion process of the device is in a stable transition state, and no current sudden change exists, so that the forward conduction is free of Snapback phenomenon.

FIG. 11 is a diagram showing the current distribution inside the transistors when the conventional RC-LIGBT and the novel RC-LIGBT device are turned on in the forward direction, and for the point A in FIG. 10, the PN junction between the N-buffer and the P-Collector of the novel RC-LIGBT Collector is not turned on, so that the diagram shows a unipolar conduction mode diagram, in which the LDMOS is the dominant conduction mode, and the LIGBT region, the P-Collector, for the N-emitter of the slave emitter, is a unipolar conduction mode diagram⁺The electrons flowing out belong to a high potential barrier, and the electrons are prevented from flowing to a collector, so that no current is generated; for point B in fig. 10, the PN junction voltage between the N-buffer and the P-Collector of the novel RC-LIGBT device has already reached above 0.6V, so it is shown as a bipolar conduction mode diagram, where the conduction mode is dominated by LIGBT and the current in the LDMOS region is very limited; for point C in fig. 10, a PN junction between an N-buffer and a P-Collector of a Collector of the conventional RC-LIGBT device is not opened, and at this time, only electrons are conducted as carriers, the N-Collector is an electron current of the Collector, and electrons flow through the N-Collector at a low barrier, and the P-Collector is a high barrier, and electrons are not allowed to flow through the P-Collector, as shown in fig. 11, the electrons only flow through the N-Collector at this time; for point D in fig. 10, the PN junction between the N-buffer and the P-Collector of the conventional RC-LIGBT device is turned on, and at this time, not only electrons injected from the electron emission region into the N-drift region are conducted as carriers, but also holes emitted from the P-Collector are conducted as carriers, as shown in fig. 11, both electrons and holes participate in the conduction, and at this time, the PN junction between the N-buffer and the P-Collector of the conventional RC-LIGBT device is turned on, and at this time, as shown in fig. 11, both electrons and holes participate in the conductionThe conductance modulation effect appears in the N-drift region, the resistance on the amperemeter path is reduced, the Snapback phenomenon appears in the traditional RC-LIGBT device, and the L-type SiO is introduced₂The novel RC-LIGBT device of the isolation layer introduces L-type SiO₂The whole conducting process of the isolating layer is mainly from LDMOS to LDMOS + LIGBT mixed mode and then from LIGBT conducting mode, the current of the device is in a stable transition state in the current conversion process, and the resistance cannot generate sudden change, so that the forward conduction is free from Snapback phenomenon.

FIG. 12 simulates the proposed novel RC-IGBT device by controlling L-type SiO₂The position of the isolation layer is used for controlling the area Ratio of the LDMOS region and the LIGBT region, and the output characteristics of the LDMOS region and the LIGBT region are longitudinally compared by using MEDICI software. The Ratio values in these four cases are respectively: 1:3, 1:2, 1:1, 2: 1. It can be seen that the forward conduction characteristics of the device are different at four different values of Ratio. As the area of the LDMOS region is increased, the area of the LIGBT region is reduced, namely the Ratio is increased, the current sectional area of a drift region near a collector of the LDMOS region is increased, and the value is represented by R ═ rho_*(L/S) knowing that the resistance of the drift region of the LDMOS region is reduced, explaining the reason that the collector current with a large Ratio value is large when the LIGBT region does not reach the threshold voltage VPN of a PN junction formed by a P-collector and an N-buffer under the conditions that the Ratio shown in a small graph in FIG. 10 is at 1:3, 1:2, 1:1 and 2:1 and the collector voltage is 0.6V, namely the device is still in a unipolar conduction mode dominant in the LDMOS region; after the PN junction is opened after the voltage is more than 0.6V, the P-collector starts to inject holes into the drift region, so that the conduction mode of the device is dominated by the bipolar conduction mode of the LIGBT region, when the Ratio is 1:3, 1:2, 1:1 and 2:1, namely the Ratio is gradually increased, the length L of a current path of the drift region of the LIGBT region is increased, and the sectional area S is reduced. The drift region resistance R increases and the change in resistance is slope dependent in the I-V characteristic. Therefore, when the Ratio is respectively 1:3, 1:2, 1:1 and 2:1, the gradient magnitude sequence of the bipolar conduction mode is just opposite to that of the corresponding I-V characteristic curve in the unipolar conduction mode. This trend can be seen in fig. 12. Since the influence of the Ratio on the device is large, this is a characteristic parameter that can be studied in depth.

FIG. 13 shows the current distribution diagram inside the device under the forward conduction mode of the novel RC-IGBT device obtained by simulation under the MEDICI environment, and it can be seen that the L-type SiO is controlled₂The area Ratio of the LDMOS region and the LIGBT region is controlled by the position of the isolation layer, and the current distribution of the LDMOS region and the LIGBT region is longitudinally compared by using a simulation result of MEDICI software. In the L-form of SiO₂When the horizontal length D of the isolating layer is 5.368 mu m, the Ratio of Ratio is 1: 3; in the L-form of SiO₂When the horizontal length D of the isolating layer is 7.517 μm, the Ratio of Ratio is 1: 2; in the L-form of SiO₂When the horizontal length D of the isolation layer is 10.07 mu m, the Ratio of Ratio is 1:1, and the L-type SiO₂When the horizontal length D of the spacer is 14.3157 μm, the Ratio of Ratio is 2: 1. The change in current path length L and cross-sectional area S with Ratio described for fig. 12 is readily seen in fig. 13. By adjusting the value of Ratio, the drift region areas of the LDMOS region and the LIGBT region in the novel RC-LIGBT device are directly controlled, and become key parameters influencing the device performance.

FIG. 14 shows the concentration Nd of 1 × 10 in the drift region of conventional LDMOS, conventional LIGBT, conventional RC-LIGBT and novel RC-LIGBT devices¹⁴The graph is compared with the relationship curve of the emitter voltage and the reverse current density at the time of reverse conduction processed by Origin software. As shown in fig. 14, it is obvious that no current is generated in the conventional LIGBT device under any emitter reverse bias voltage, and the reverse output characteristic curve is always a horizontal straight line with a coordinate I equal to 0; under the condition of the same parameters, the traditional LDMOS device, the traditional RC-LIGBT device and the novel RC-LIGBT device have good reverse conduction characteristics and generate large reverse current, and it can be seen that after the traditional LDMOS device, the traditional LDMOS device and the novel RC-LIGBT device are completely conducted, the traditional LDMOS device has the largest current under the same emitter voltage, the novel RC-LIGBT device has the second lowest current, and the traditional RC-LIGBT device has the smallest current. However, as can be seen from the figure, the magnitude relationship is opposite to the sequence when the emitter is larger than-0.5V, and then the PN junction formed by the P-body and the N-drift is not opened, only the electrons in the active region participate in conduction, so the parameters of the N-collector for receiving the electrons are particularly important. Two reasons are further analyzed: (1) under the condition that the area of the collector is the same, the N-collector part of the collector region has different occupation ratios, and the N-collector part of the collector region has different occupation ratios in the traditional methodThe collector region in the LDMOS device is only an N-collector region with the largest area ratio, while the collector of the traditional RC-LIGBT device consists of the N-collector and the P-collector, the occupation ratio of the collector region is far smaller than that of the traditional LDMOS device, and the collector region is provided with L-type SiO₂The novel RC-LIGBT device of the isolation layer has independent N-collector and P-collector areas, so that the area ratio is adjustable; (2) under the same size parameter, the independent LDMOS region of the novel RC-LIGBT device is closer to the emitter region, the drift region is short, and the series resistance R of the novel RC-LIGBT device is caused_dSmall, making the current more sensitive to voltage.

FIG. 15 shows the variation curve of the reverse current of the novel RC-LIGBT device with the emitter bias voltage drawn by Origin when the Ratio of the novel RC-LIGBT device is 1:3, 1:2, 1:1 and 2:1 respectively in reverse conduction, and it can be seen that the magnitude of the reverse current of the RC-LIGBT device has a certain correlation with the variation of the Ratio because the proposed device has L-shaped SiO₂The novel RC-LIGBT device of the isolation layer has independence in reverse direction, reverse working capacity is completely provided by the LDMOS region, and the LIGBT region does not participate in the reverse working of the device, as shown in FIG. 15, the novel RC-LIGBT device serving as a transverse device has smaller area current density under the same emitter reverse bias voltage along with the increase of the area Ratio of the LDMOS region to the LIGBT region, that is to say, the area is larger because the length L of the drift region is longer, so that the novel RC-LIGBT device has more uniform current distribution, under the same parameter condition, the area current density is reduced along with the increase of the area of the LDMOS region, but the current capacity in reverse conduction is stronger.

FIG. 16 shows a simulation environment with L-shaped SiO₂When the novel RC-LIGBT device of the isolation layer is in a reverse conducting state, and when the bias voltage of an emitting electrode is-0.7539V, and the Ratio values are 1:3, 1:2, 1:1 and 2:1, the internal current distribution diagram of the device is obtained. When Raio is 1:3, the current size is-4.44481 × 10^-5A, the area current density is-154.25098A/cm²(ii) a When Raio is 1:2, the current size is-8.04489 × 10^-5A, the area current density is-142.37406A/cm²(ii) a When Raio is 1:1, the current size is-1.06981 × 10^-4A, the area current density is-105.49921A/cm²(ii) a When Raio is 2:1,the current is-1.67741 multiplied by 10^-4A, the area current density is-81.84914A/cm²(ii) a According to the data, under the reverse conducting state with the same bias voltage, the area current density of the novel RC-LIGBT device is reduced along with the increase of the Ratio, and the simulation result shows that the current distribution of the device is more uniform along with the increase of the Ratio, the possibility of local high temperature of a transistor can be reduced, the temperature characteristic is optimized, and the thermal stability is improved; on the other hand, the current magnitude increases with the increase of the Ratio, because the increase of the length of the LDMOS region means the increase of the cross-sectional area of the drift region, and the current capability of the device with the larger Ratio is stronger under the same size. Therefore, the areas of the LDMOS part and the LIGBT part in the novel RC-LIGBT device can be controlled through the change of the Ratio, so that the directivity requirements of the device on specific electrical properties, such as forward conduction property, reverse conduction property, breakdown property and the like, under the application of different engineering environments are adjusted.

FIG. 17 is Origin treated SiO with L form₂As shown in fig. 17, when the Ratio values are 1:1.5, 1:1, 1.5:1, and 2:1, respectively, the drift region length D of the LDMOS region is: 8.589 μm, 10.07 μm, 12.88 μm, 14.3175 μm; obviously, the turn-off time of the novel RC-LIGBT is closely related to the value of Ratio. This is because the variation in Ratio directly affects the variation in the drift region length L of the LIGBT region, thereby affecting the sweep rate of excess carriers when the collector voltage increases at the time of turn-off. As the area of the LIGBT region becomes smaller and the turn-off speed becomes faster and faster, when Ratio is 1:1.5, it takes 2.9256 mus for the device to turn off from 100A to 62.7741 a; when Ratio is 1:1, it takes 2.3985 μ s for the device to turn off from 100A to 59.7136 a; when Ratio is 1.5:1, the device collector voltage increase contributes little to the current turn-off; when Ratio is 2:1, it takes 1.4318 μ s for the device to turn off from 100A to 57.09666 a; unfortunately, however, this has the L-form of SiO₂The turn-off performance of the isolation layer device has yet to be studied in depth, and the L-shaped SiO₂The influence of the area ratio of the two independent working areas of the novel RC-LIGBT of the isolation layer on each performance of the device needs to be studied deeply.

In summary, the present inventionProposed is L-type SiO₂The novel RC-LIGBT of the isolation layer has the following characteristics through simulation verification:

(11) breakdown characteristics: l-type SiO₂The isolation layer leads the surface electric field of the transistor into the body, greatly enhances the internal electric field, reduces the electric field peak of the device, and avoids the breakdown on the surface of the device in advance, thereby improving the breakdown voltage. Under the condition of the same parameters, the breakdown voltage reaches 206.05V, which is 107% higher than the breakdown voltage 99.491V of the traditional RC-LIGBT.

(2) Forward conduction characteristic: first, the LDMOS region is in a unipolar conduction mode, and electrons are driven from the N of the LDMOS⁺The emitter is injected into the drift region of the LDMOS and flows out of the drain after flowing through the N-buffer. LIGBT zone N at this time⁺And in the second step, as the Collector voltages of the LDMOS region and the LIGBT region are increased, the Collector P-Collector of the LIGBT region starts to inject holes into the drift region, and at the moment, the LIGBT + LDMOS conduction mode is adopted. Thirdly, as the collector voltage continues to increase, because the LIGBT region adopts a bipolar conduction mode, the current exponentially increases along with the voltage, so that the device conduction is mainly based on the bipolar conduction mode of the LIGBT region S2; the whole conducting process is from LDMOS being the main mode to LDMOS + LIGBT mixed mode and then to LIGBT being the main mode, the current is in stable transition in the current conversion process of the device and is in stable transition in the forward conducting mode, and the resistance cannot be suddenly changed, so that the forward conducting mode has no Snapback phenomenon.

(3) Reverse conduction characteristic: the LDMOS region may be equivalent to a PN junction formed by a P-body and an N-drift region, and the N-collector has a low potential barrier relative to electrons and allows electron current to flow through. The LIGBT region can be equivalent to a back-to-back diode composed of a P-body, an N-drift region and a P-collector, i.e. a PNP structure, wherein the PN junction formed by the P-body and the N-drift region is forward biased, and the PN junction formed by the N-drift region and the P-collector is reverse biased, so that no electron current is allowed to flow. The novel RC-LIGBT has good independence on reverse operation and excellent reverse operation characteristic.

The invention provides a novel tool withL-type SiO₂The novel RC-LIGBT of the isolation layer takes a schematic diagram 4 as an example, and the specific implementation method comprises the following steps: selecting P type<100>Grain-oriented zone-melting single crystal liner for growing SiO₂And (4) forming an SOI structure by epitaxially growing an L-shaped N-drift region of the LIGBT on the dielectric isolation layer. And etching a groove-shaped region in the N-drift region based on the SOI structure, firstly completing an LIGBT emitter region, firstly injecting high-concentration ions, and carrying out high-temperature junction on the P-body and N + regions on the left side. Then growing left gate oxide, gate electrode, gate oxide, and large L-shaped SiO₂And isolating the layer to complete the LIGBT region. Performing epitaxy again to form an N-drift region of the LDMOS, etching a groove-shaped region in the N-drift region, and continuing ion implantation to form an N + region, namely a P-body; and then respectively forming collectors N-Collector and P-Collector of the LDMOS and the LIGBT by ion implantation on the surface. Finally, the emitter collector metal is punched and deposited. Finally passivated and packaged, etc.

In the implementation process, according to the design requirements of specific devices, the invention provides the L-shaped SiO₂When the novel RC-LIGBT of the isolation layer is specifically manufactured, the substrate material can be silicon Si material, and can also be silicon carbide, gallium arsenide, indium phosphide, germanium silicon or other semiconductor materials instead of bulk silicon.

Finally, it is noted that the above-mentioned preferred embodiments illustrate rather than limit the invention, and that, although the invention has been described in detail with reference to the above-mentioned preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the invention as defined by the appended claims.

Claims

1. L-shaped SiO₂The composite RC-LIGBT device of the isolation layer is characterized by comprising L-type SiO₂An isolation layer (16), an LDMOS region (S1), an LIGBT region (S2), a collector (7), and a common active region;

the composite RC-LIGBT device is formed by the L-shaped SiO₂The isolation layer (16) is divided to form an LDMOS region (S1) of an upper left region and an LIGBT region (S2) of a lower right region;

the common active region comprises a source electrode(4) The gate oxide layer (3) is positioned on the source electrode (4) and the L-shaped SiO₂Between the horizontal ends of the isolation layer (16), the gate oxide layer (3) completely surrounds the gate electrode (2).

2. The method of claim 1, wherein the SiO has an L-shape₂Composite RC-LIGBT device with isolation layer, wherein the LDMOS region (S1) comprises a P-body heavily doped P from left to right⁺The field effect transistor comprises a region (13), a lightly doped P region (5), a rectangular N-drift region (6), an arc N-buffer region (9) and an N-Collector region (12); wherein the P-body is heavily doped with P⁺The region (13) is connected to the source (4).

3. The method of claim 2, wherein the SiO has an L-shape₂The composite RC-LIGBT device with the isolation layer is characterized in that the LDMOS region (S1) further comprises an N + electron emitter (1), the left surface of the N + electron emitter (1) is in contact with a source electrode (4), and the upper surface of the N + electron emitter is in contact with a heavily doped P of a P-body⁺The region (13) is in contact with the lightly doped P region (5) on the right and the gate oxide layer (3) on the lower side.

4. The method of claim 1, wherein the SiO has an L-shape₂The composite RC-LIGBT device of the isolation layer is characterized in that the horizontal direction of the LIGBT region (S2) is sequentially provided with heavily doped P-body P from left to right⁺A region (13), a lightly doped P region (5), an L-shaped N-drift region (15), wherein the P-body is heavily doped with P⁺The region (13) is connected to the source (4).

5. The method of claim 4, wherein the SiO has an L-shape₂The composite RC-LIGBT device of the isolation layer is characterized in that the LIGBT region (S2) further comprises an N + electron emitter (1), the left surface of the N + electron emitter (1) is in contact with a source electrode (4), the upper surface of the N + electron emitter is in contact with a gate oxide layer (3), the right surface of the N + electron emitter is in contact with a lightly doped P region (5), and the lower surface of the N + electron emitter is in contact with a heavily doped P region of a P-body⁺The regions (13) are in contact.

6. An appliance as claimed in claim 4With L-form SiO₂The composite RC-LIGBT device of the isolation layer is characterized in that the LIGBT region (S2) further comprises an N-buffer region (14) arranged above the vertical end of the L-shaped N-drift region (15) and a P-Collector region (8) positioned above the N-buffer region (14).

7. The method of claim 1, wherein the SiO has an L-shape₂The composite RC-LIGBT device of the isolation layer is characterized in that the lower part of the Collector (7) is sequentially connected with the N-Collector region (12) and the L-type SiO from left to right₂The vertical end of the isolation layer (16) is contacted with the P-Collector area (8).