CN213660420U - Gallium nitride schottky barrier diode - Google Patents
Gallium nitride schottky barrier diode Download PDFInfo
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- CN213660420U CN213660420U CN202023324529.9U CN202023324529U CN213660420U CN 213660420 U CN213660420 U CN 213660420U CN 202023324529 U CN202023324529 U CN 202023324529U CN 213660420 U CN213660420 U CN 213660420U
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Abstract
A Schottky barrier diode of gallium nitride relates to a power semiconductor device of gallium nitride. The drift region comprises a substrate, a transition layer, a drift layer, an active region, a drift channel, a field plate and a metal electrode layer; the active region comprises a drift layer and an active region first semiconductor layer which are sequentially connected; the active region first semiconductor layer, the drift layer and the two drift channels form an annular drift region structure, and compared with a transverse gallium nitride Schottky barrier diode structure only with a transverse drift region or a vertical gallium nitride Schottky barrier diode structure only with a vertical drift region, the total path length of the drift region is larger than that of a transverse device structure manufactured on the same substrate and epitaxial layer, and therefore the blocking voltage of the gallium nitride Schottky barrier diode is increased. The scheme has the characteristics that the blocking voltage of the device is improved, and meanwhile, the anode electrode, the cathode electrode and the field plate electrode are gathered on the top surface of the device structure to form a coplanar device input and output electrode structure, so that the planar integration of the device is facilitated, and the like.
Description
Technical Field
The utility model relates to a gallium nitride power semiconductor device, especially a gallium nitride schottky barrier diode of high blocking voltage belongs to power electronic device technical field.
Background
Gallium nitride materials, which are typical representatives of third-generation semiconductors, have the advantages of large forbidden band width, high breakdown electric field, high thermal conductivity, high electron saturation drift rate, strong radiation resistance and the like, and gallium nitride Schottky Barrier Diodes (SBDs) have wide application prospects in the fields of 5G mobile communication, semiconductor illumination, consumer electronics and the like due to the advantages of high blocking voltage, high switching speed, low power consumption and the like.
The gallium nitride Schottky barrier diode in the prior art mainly adopts two structural forms of a vertical SBD based on a GaN body material and a transverse SBD based on AlGaN/GaN and other heterojunction two-dimensional electron gas (2 DEG).
The vertical type gallium nitride Schottky barrier diode is manufactured on a gallium nitride semiconductor substrate with a homoepitaxy, the vertical type gallium nitride Schottky barrier diode in the prior art generally increases the blocking voltage by increasing the longitudinal thickness of a drift region, a high-power density chip is realized, but the defect density of a gallium nitride epitaxial semiconductor layer is in direct proportion to the thickness of the epitaxial layer, the defect density in the gallium nitride semiconductor epitaxial layer with larger thickness is larger, the improvement of performance indexes such as key blocking voltage and reverse leakage current of a device is influenced, and the preparation and application of the gallium nitride Schottky barrier diode based on a self-supporting gallium nitride substrate are limited by the defects of the prior gallium nitride substrate preparation technology in size and cost.
The lateral type GaN Schottky barrier diode is manufactured on a hetero-epitaxial GaN semiconductor substrate, and the epitaxial substrate is a low-cost silicon substrate, or a silicon carbide substrate or a sapphire substrate. Compared with a vertical type gallium nitride SBD, because 2DEG electron concentration is high, mobility is high, and the AlGaN/GaN heterojunction based transverse type gallium nitride SBD has the characteristics of small contact resistance, small junction capacitance, high cut-off frequency and the like, a transverse type gallium nitride Schottky barrier diode in the prior art generally obtains higher blocking voltage by a method of increasing inter-electrode spacing, namely increasing the length of a drift region, so that the chip size and the on-resistance of a device can be increased, effective current density and chip performance on a unit chip area are reduced, the defect density of a gallium nitride semiconductor epitaxial layer manufactured on a heterogeneous material is higher, and the improvement of performance indexes of key blocking voltage, on-resistance, reverse leakage current and the like of the device is influenced.
In addition, the anode electrode in the gan schottky barrier diode with the vertical structure is positioned on the top surface of the device structure, and the cathode electrode is positioned on the bottom surface of the device structure, or the cathode electrode is positioned on two sides of the bottom of the mesa by manufacturing the mesa structure, and the anode electrode and the cathode electrode are both non-coplanar input and output electrode structures, which is not convenient for the planar integration of the device and the application thereof in a power integrated circuit.
SUMMERY OF THE UTILITY MODEL
The utility model discloses to above problem, provide an adopt two-dimentional annular drift district structure, the length in drift district in the increase device structure improves the blocking voltage of device, makes positive pole electrode, cathode electrode and field plate electrode gather in the top surface of device structure simultaneously, forms coplane device input/output electrode structure, the plane integration of the device of being convenient for and the gallium nitride schottky barrier diode who uses in power integrated circuit.
The technical scheme of the utility model is that:
the gallium nitride Schottky barrier diode comprises a substrate, a transition layer, a drift layer, an active region, a drift channel, a field plate and a metal electrode layer;
the substrate, the transition layer and the drift layer are sequentially connected from bottom to top;
the number of the drift channels is two, and the active regions are connected with the upper end of the drift layer respectively;
the two drift channels are respectively positioned at two sides of the active region and are isolated from the active region through an isolating layer in the drift channels;
the active region comprises a drift layer and an active region first semiconductor layer which are sequentially connected from bottom to top;
the drift channel comprises a channel drift layer and a drift channel ohmic contact layer which are sequentially connected from bottom to top, and an inner drift channel isolation layer and an outer drift channel isolation layer which are positioned on the inner side and the outer side of the channel drift layer and the inner side and the outer side of the drift channel ohmic contact layer;
the number of the field plates is two; the two field plates are respectively embedded into the corresponding separation layers in the drift channels;
the metal electrode layer comprises an anode electrode, a cathode electrode and a field plate electrode;
the anode electrode is positioned on the top of the active region and is connected with the first semiconductor layer of the active region;
the cathode electrode is positioned at the top of the drift channel and is connected with the ohmic contact layer of the drift channel;
the field plate electrode is connected to the top of the field plate and is isolated from the active region by a field plate insulating layer.
The substrate is a Si substrate, a SiC substrate or a sapphire substrate.
The transition layer includes an AlN epitaxial layer.
The AlGaN epitaxial layer is connected to the AlN epitaxial layer from bottom to top.
The first semiconductor layer, the drift layer and the channel drift layer of the active region are respectively N―GaN epitaxial layer or P―-a GaN epitaxial layer;
the ohmic contact layer of the drift channel is N+GaN epitaxial layer or P+-a GaN epitaxial layer.
The inner isolation layer of the drift channel, the outer isolation layer of the drift channel and the field plate insulation layer are respectively a silicon dioxide layer or a silicon nitride layer.
The field plate is a Ti/Au double-metal layer.
The anode electrode is a Ni/Au bimetallic layer.
The cathode electrode and the field plate electrode are respectively a Ti/Al/Ti/Au multi-metal layer or a Cr/Al/Ti/Au multi-metal layer.
The utility model comprises a substrate, a transition layer, a drift layer, an active region, a drift channel, a field plate and a metal electrode layer; the active region comprises a drift layer and an active region first semiconductor layer which are sequentially connected from bottom to top; the drift channel comprises a channel drift layer and a drift channel ohmic contact layer which are sequentially connected from bottom to top, and an inner drift channel isolation layer and an outer drift channel isolation layer which are positioned on the inner side and the outer side of the channel drift layer and the inner side and the outer side of the drift channel ohmic contact layer; active area first semiconductor layer, drift layer and two drift passageways constitute an annular drift region structure, for only there is the horizontal type gallium nitride schottky barrier diode structure in horizontal drift region or only there is the perpendicular type gallium nitride schottky barrier diode structure in perpendicular drift region, the utility model provides a path total length in drift region is greater than the path length of drift region in the gallium nitride schottky barrier diode of the horizontal type device structure of the same base plate and epitaxial layer size or the perpendicular type device structure of preparation, increases gallium nitride schottky barrier diode's blocking voltage from this. The utility model has the characteristics of improve the blocking voltage of device, make positive pole electrode, cathode electrode and field plate electrode gather in the top surface of device structure simultaneously, form coplane device input/output electrode structure, the plane integration of the device of being convenient for and use in power integrated circuit etc.
Drawings
Figure 1 is a schematic structural view of the present invention,
figure 2 is a schematic structural diagram of step 4 of the present invention,
figure 3 is a schematic structural diagram of step 6 of the present invention,
figure 4 is a schematic structural diagram of step 8 of the present invention,
figure 5 is a schematic diagram of the structure of step 10 of the present invention,
figure 6 is a schematic structural diagram of step 13 of the present invention,
fig. 7 is a schematic structural diagram of step 18 of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present invention, and should not be construed as limiting the present invention.
The utility model discloses as shown in fig. 1-7, gallium nitride schottky barrier diode, including base plate, transition layer, drift layer, active area, drift passageway, field plate and metal electrode layer;
the substrate, the transition layer and the drift layer are sequentially connected from bottom to top;
the number of the drift channels is two, and the active regions are connected with the upper end of the drift layer respectively;
the two drift channels are respectively positioned at two sides of the active region and are isolated from the active region through an isolating layer in the drift channels;
the active region comprises a drift layer and an active region first semiconductor layer which are sequentially connected from bottom to top;
the drift channel comprises a channel drift layer and a drift channel ohmic contact layer which are sequentially connected from bottom to top, and an inner drift channel isolation layer and an outer drift channel isolation layer which are positioned on the inner side and the outer side of the channel drift layer and the inner side and the outer side of the drift channel ohmic contact layer; (the dashed box in FIG. 1 indicates that the drift channel extends in the direction of the spacer in the drift channel, and that the entire spacer in the drift channel is included, but that the field plate is included, so that a part of the spacer in the drift channel is enclosed)
The number of the field plates is two; the two field plates are respectively embedded into the corresponding separation layers in the drift channels;
the metal electrode layer comprises an anode electrode (Schottky electrode), a cathode electrode and a field plate electrode;
the anode electrode is positioned on the top of the active region and is connected with the first semiconductor layer of the active region;
the cathode electrode is positioned at the top of the drift channel and is connected with the ohmic contact layer of the drift channel;
the field plate electrode is connected to the top of the field plate and is isolated from the active region by a field plate insulating layer.
The substrate is a Si substrate, a SiC substrate or a sapphire substrate.
The transition layer includes an AlN epitaxial layer.
The AlGaN epitaxial layer is connected to the AlN epitaxial layer from bottom to top.
The first semiconductor layer, the drift layer and the channel drift layer of the active region are N―-GaN epitaxial layer, or P―-a GaN epitaxial layer;
the ohmic contact layer of the drift channel is N+-GaN epitaxial layer, or P+-a GaN epitaxial layer. The inner isolation layer of the drift channel, the outer isolation layer of the drift channel and the field plate insulation layer are respectively a silicon dioxide layer or a silicon nitride layer.
The field plate is a Ti/Au double-metal layer.
The anode electrode (Schottky electrode) is a Ni/Au double-metal layer.
The cathode electrode and the field plate electrode are respectively a Ti/Al/Ti/Au multi-metal layer or a Cr/Al/Ti/Au multi-metal layer.
The preparation method of the gallium nitride Schottky barrier diode comprises the following steps:
1) preparing a 6-inch Si substrate, a SiC substrate or a sapphire substrate;
2) growing an AlN transition layer with the thickness of 0.5 mu m on the substrate by adopting a Metal Organic Chemical Vapor Deposition (MOCVD) method;
3) growing N with the thickness of 8 mu m on the transition layer by adopting an MOCVD method―GaN drift layer, Si doping concentration 1x1016cm-3；
4) Growing N with the thickness of 1 mu m on the drift layer by adopting an MOCVD method+GaN ohmic contact layer with Si doping concentration of 6x1019 cm-3(ii) a As shown in fig. 2;
5) using Reactive Ion Etching (RIE) or Inductively Coupled Plasma (ICP) to equal depthEtching N by ion dry etching method+-GaN ohmic contact layer and N―-a GaN drift layer forming an inner drift channel isolation layer trench and an outer drift channel isolation layer trench;
6) depositing insulating oxide (SiO) by Plasma Enhanced Chemical Vapor Deposition (PECVD)2) Filling the trench of the isolation layer in the drift channel and the trench of the isolation layer outside the drift channel to form the isolation layer in the drift channel and the isolation layer outside the drift channel; as shown in fig. 3;
7) etching the isolation layers in the two drift channels by adopting an RIE (reactive ion etching) or ICP (inductively coupled plasma) method to form a field plate groove;
8) depositing Ti/Au to fill the field plate groove by adopting an electron beam sputtering or magnetron sputtering method to form a field plate; as shown in fig. 4;
9) etching N between the isolation layers in the two drift channels by adopting RIE (reactive ion etching) or ICP (inductively coupled plasma) method+GaN ohmic contact layer and part of N―-a GaN drift layer forming an active region recess;
10) n communicated with drift layer with thickness of 5.5 mu m is grown in the groove of active region by MOCVD method―-a GaN active area first semiconductor layer filled with active area grooves with a Si doping concentration of 1x1016 cm-3(ii) a As shown in fig. 5;
11) forming a photoresist mask layer for manufacturing the field plate insulating layer by adopting a photoetching method;
12) depositing a silicon dioxide layer or a silicon nitride layer for manufacturing the field plate insulating layer by adopting a low-pressure chemical vapor deposition (LPCVD) method;
13) forming a field plate insulating layer by a stripping method; as shown in fig. 6;
14) forming a photoresist mask layer for manufacturing an anode electrode (Schottky electrode) by adopting a photoetching method;
15) depositing a Ni/Au multi-metal layer by adopting an electron beam sputtering or magnetron sputtering method;
16) forming an anode electrode (schottky electrode) by a lift-off method;
17) forming a photoresist mask layer for manufacturing a cathode electrode and a field plate electrode by adopting a photoetching method;
18) depositing a Ti/Al/Ti/Au multi-metal layer by adopting an electron beam sputtering or magnetron sputtering method, and forming a cathode electrode and a field plate electrode by adopting a stripping method; as shown in fig. 7;
19) using 600 ℃ and N2The method of annealing in the atmosphere forms ohmic contacts for the cathode electrode and the respective semiconductor layer.
The utility model discloses the work flow of device:
the utility model provides a first semiconductor layer and anode electrode (schottky electrode) form the schottky contact, constitute the utility model discloses a gallium nitride schottky barrier diode's functional area structure, first semiconductor layer is used as the drift layer simultaneously, and second semiconductor layer is used as the ohmic contact who forms cathode electrode. The gallium nitride schottky barrier diode is turned on when forward biased. During reverse bias, the gallium nitride schottky barrier diode has higher blocking voltage because of the big forbidden band width that the gallium nitride material has, high breakdown field characteristics, and because the utility model discloses the total path length in cyclic annular drift region is greater than the path length of drift region among the gallium nitride schottky barrier diode of the lateral structure of preparation on the same dimension's base plate and epitaxial layer or vertical component structure, further improves gallium nitride schottky barrier diode's blocking voltage from this, makes the anode electrode of device, cathode electrode and field plate electrode gather in the top surface of its structure simultaneously, forms coplanar device input/output electrode structure, is convenient for realize the plane integration of device and the application in power integrated circuit.
The utility model provides a first semiconductor layer in active area, drift layer and two drift passageways constitute an annular drift region structure, for the horizontal type gallium nitride schottky barrier diode structure that only has the horizontal drift region or the vertical type gallium nitride schottky barrier diode structure that only has the vertical drift region, the utility model provides a path total length in drift region is greater than the path length of the drift region of preparation in the gallium nitride schottky barrier diode of the horizontal type device structure of same base plate and epitaxial layer size or vertical type device structure, increases gallium nitride schottky barrier diode's blocking voltage from this.
The utility model discloses well field plate perhaps applys the electric potential alone through field plate electrode, perhaps connects the anode electrode and applys the electric potential, perhaps connects the cathode electrode and applys the electric potential, optimizes the electric field distribution on the cyclic annular drift route, further improves gallium nitride schottky barrier diode's blocking voltage.
Compare in the horizontal type gallium nitride schottky barrier diode that requires longer horizontal drift region or require the perpendicular type gallium nitride schottky barrier diode in the perpendicular drift region of thick, the utility model discloses the structure of specific cyclic annular current drift region does not require longer or thicker gallium nitride epitaxial layer, can utilize the more ripe of technology among the prior art, and the silicon-based gallium nitride substrate material of lower price makes the gallium nitride schottky barrier diode of high blocking voltage, satisfies the demand of extensive application.
And simultaneously, the utility model discloses distinctive cyclic annular current drift district structure collects the top surface at the structure with the anode electrode, cathode electrode and the field plate electrode of device, promptly the utility model discloses a gallium nitride schottky barrier diode has coplane input/output electrode structural feature, is convenient for realize that the device plane integrates and be applied to in the power integrated circuit.
The utility model discloses in be used for adjusting the field plate of knot terminal electric field can apply the power alone through the field plate electrode, perhaps connect the positive pole electrode and apply same power potential, perhaps connect the negative pole electrode and apply same power potential.
The utility model discloses an each structural element is circular or arbitrary polygon structure, correspondingly, the utility model discloses a device chip appearance is circular or arbitrary polygon.
The disclosure of the present application also includes the following points:
(1) the drawings of the embodiments disclosed herein only relate to the structures related to the embodiments disclosed herein, and other structures can refer to general designs;
(2) in case of conflict, the embodiments and features of the embodiments disclosed in this application can be combined with each other to arrive at new embodiments;
the above embodiments are only embodiments disclosed in the present disclosure, but the scope of the disclosure is not limited thereto, and the scope of the disclosure should be determined by the scope of the claims.
Claims (9)
1. The gallium nitride Schottky barrier diode is characterized by comprising a substrate, a transition layer, a drift layer, an active region, a drift channel, a field plate and a metal electrode layer;
the substrate, the transition layer and the drift layer are sequentially connected from bottom to top;
the number of the drift channels is two, and the active regions are connected with the upper end of the drift layer respectively;
the two drift channels are respectively positioned at two sides of the active region and are isolated from the active region through an isolating layer in the drift channels;
the active region comprises a drift layer and an active region first semiconductor layer which are sequentially connected from bottom to top;
the drift channel comprises a channel drift layer and a drift channel ohmic contact layer which are sequentially connected from bottom to top, and an inner drift channel isolation layer and an outer drift channel isolation layer which are positioned on the inner side and the outer side of the channel drift layer and the inner side and the outer side of the drift channel ohmic contact layer;
the number of the field plates is two; the two field plates are respectively embedded into the corresponding separation layers in the drift channels;
the metal electrode layer comprises an anode electrode, a cathode electrode and a field plate electrode;
the anode electrode is positioned on the top of the active region and is connected with the first semiconductor layer of the active region;
the cathode electrode is positioned at the top of the drift channel and is connected with the ohmic contact layer of the drift channel;
the field plate electrode is connected to the top of the field plate and is isolated from the active region by a field plate insulating layer.
2. The gan schottky barrier diode as described in claim 1, wherein the substrate is a Si substrate, a SiC substrate, or a sapphire substrate.
3. The gan schottky barrier diode as described in claim 1, wherein the transition layer comprises an AlN epitaxial layer.
4. The gan schottky barrier diode as described in claim 3, further comprising an AlGaN epitaxial layer connected to the AlN epitaxial layer from bottom to top.
5. The gan schottky barrier diode as claimed in claim 1, wherein the first semiconductor layer, the drift layer and the channel drift layer of the active region are N―GaN epitaxial layer or P―-a GaN epitaxial layer;
the ohmic contact layer of the drift channel is N+GaN epitaxial layer or P+-a GaN epitaxial layer.
6. The gan schottky barrier diode as claimed in claim 1, wherein the inner drift channel isolation layer, the outer drift channel isolation layer and the field plate isolation layer are silicon dioxide layer or silicon nitride layer, respectively.
7. The gan schottky barrier diode as described in claim 1, wherein the field plate is a Ti/Au bi-metal layer.
8. The gan schottky barrier diode as described in claim 1, wherein the anode electrode is a Ni/Au bimetallic layer.
9. The gan schottky barrier diode as described in claim 1, wherein the cathode electrode and the field plate electrode are Ti/Al/Ti/Au multi-metal layers or Cr/Al/Ti/Au multi-metal layers, respectively.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202023324529.9U CN213660420U (en) | 2020-12-31 | 2020-12-31 | Gallium nitride schottky barrier diode |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202023324529.9U CN213660420U (en) | 2020-12-31 | 2020-12-31 | Gallium nitride schottky barrier diode |
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| Publication Number | Publication Date |
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| CN213660420U true CN213660420U (en) | 2021-07-09 |
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| CN202023324529.9U Active CN213660420U (en) | 2020-12-31 | 2020-12-31 | Gallium nitride schottky barrier diode |
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