Power device
By setting a donor contribution layer in the power device and controlling the carbon doping concentration, the resistance offset problem of gallium nitride high electron mobility transistors is improved, the dynamic resistance characteristics and crystal quality of the device are enhanced, and the device is prevented from being damaged at high temperature or high voltage.
Patent Information
- Application Number
- CN202422944740.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-29
- Publication Date
- 2025-11-18
- Estimated Expiration
- 2034-11-29
AI Technical Summary
Gallium nitride high electron mobility transistors are prone to resistance shift during long-term operation, especially as device size shrinks, which weakens their dynamic resistance characteristics.
By setting a donor contribution layer in the power device, located between the buffer layer and the high-resistivity layer, and controlling the carbon doping concentration to be lower than that of the buffer layer and the high-resistivity layer, the crystal quality of the epitaxial structure is improved, and more donor atoms are provided to compensate for acceptor impurities, thereby improving the resistance shift phenomenon.
It improves the dynamic resistance characteristics of power devices, reduces lateral leakage current, increases the vertical breakdown voltage and crystal quality of devices, and prevents devices from burning out at high temperatures or high voltages.
Smart Images
Figure CN223567988U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to power device technical field especially relates to a power device. BACKGROUND
[0002] Gallium nitride high electron mobility transistor has the characteristics of high power density, low on-resistance, high working frequency, but at present, some problems inevitably exist, such as resistance shift phenomenon under long time working condition, especially under the condition that the device size is further reduced, this phenomenon becomes more serious, the device needs to bear the voltage as large as originally under smaller area, then it will lead to the whole device more easily appearing high electric field, generating greater current, after long time working, it will lead to the electron in the channel being captured to the high-doped dielectric layer or high-doped epitaxial layer of device drift region, bringing defect center, and then generating resistance shift phenomenon, that is, weakening the dynamic resistance characteristics of the device. SUMMARY
[0003] The utility model provides a kind of power device, can improve the dynamic characteristics of power device, improve the phenomenon of resistance shift.
[0004] According to an aspect of the utility model, a kind of power device is provided, comprising:
[0005] Substrate, buffer layer, donor contribution layer, high resistance layer, channel layer and potential barrier layer are sequentially stacked and set;Donor contribution layer is used to provide donor atom for high resistance layer.
[0006] Optionally, the carbon doping concentration of the donor contribution layer is less than the carbon doping concentration of the buffer layer, and the carbon doping concentration of the donor contribution layer is less than the carbon doping concentration of the high resistance layer.
[0007] Optionally, the carbon doping concentration of the donor contribution layer ranges from 10 16 / cm 3 -10 19 / cm 3 .
[0008] Optionally, the thickness of the donor contribution layer ranges from 50nm to 300nm.
[0009] Optionally, the power device further comprises:
[0010] Nucleation layer; nucleation layer is located between substrate and buffer layer.
[0011] Optionally, the power device further comprises:
[0012] Space layer, space layer is located between potential barrier layer and channel layer.
[0013] Optionally, the power device further comprises:
[0014] a cap layer, the cap layer being located on a side of the barrier layer away from the channel layer.
[0015] Optionally, the material of the nucleation layer is the same as the material of the spacer layer.
[0016] Optionally, the thickness of the channel layer is 100nm-800nm.
[0017] Optionally, the donor contribution layer is a GaN layer or an AlGaN layer.
[0018] The power device provided by the technical scheme of the embodiment of the utility model includes: substrate, buffer layer, donor contribution layer, high resistance layer, channel layer and barrier layer which are sequentially stacked; the donor contribution layer is used for providing donor atoms for the high resistance layer. The donor contribution layer provided by the embodiment of the utility model can improve the crystal quality of the whole epitaxial structure, and on the other hand, the donor contribution layer is used for providing more donor atoms, compensating acceptor impurities in the high resistance layer and the buffer layer, improving the defect center caused by the high carbon doping concentration of the high resistance layer and the buffer layer, thereby improving the phenomenon of resistance shift.
[0019] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the utility model, nor is it used to limit the scope of the utility model. Other features of the utility model will become easy to understand through the following description. BRIEF DESCRIPTION OF DRAWINGS
[0020] In order to more clearly illustrate the technical scheme in the embodiment of the utility model, the following will briefly introduce the drawings needed to be used in the embodiment description, obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can also be obtained according to these drawings without creating labor.
[0021] Figure 1 It is a structure schematic diagram of a power device provided by the embodiment of the utility model.
[0022] Figure 2 It is a schematic diagram of atomic concentration varying with device depth provided by the embodiment of the utility model.
[0023] Figure 3 It is a structure schematic diagram of another power device provided by the embodiment of the utility model.
[0024] Figure 4 It is a structure schematic diagram of another power device provided by the embodiment of the utility model.
[0025] Figure 5 It is a structure schematic diagram of another power device provided by the embodiment of the utility model. DETAILED DESCRIPTION
[0026] In order to make the person skilled in the art better understand the technical scheme of the present application, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the protection scope of the present application.
[0027] It should be noted that the terms "first", "second" and the like in the present application are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.
[0028] The embodiment of the present application provides a power device, Figure 1 It is a structural schematic diagram of a power device provided by the embodiment of the present application, referring to Figure 1 The power device comprises: a substrate 10, a buffer layer 20, a donor contribution layer 30, a high resistance layer 40, a channel layer 50 and a barrier layer 60 which are sequentially stacked; the donor contribution layer 30 is used for providing donor atoms for the high resistance layer 40.
[0029] The power device can be a gallium nitride high electron mobility transistor; the donor contribution layer 30 covers the buffer layer 20, the high resistance layer 40 covers the donor contribution layer 30, and the channel layer 50 covers the high resistance layer; the material of the substrate 10 can include any one of silicon, sapphire, silicon nitride, boron nitride and silicon nitride. The material of the buffer layer 20 can be AlGaN, and the buffer layer 20 is used for reducing the lattice mismatch and thermal mismatch between materials and improving the crystal quality. The material of the channel layer 50 can be GaN, the channel layer 50 has very high crystal quality and is usually not doped to reduce the trap effect caused by the decrease of the drain current collapse. The material of the barrier layer 60 can be AlGaN, and the barrier layer 60 will generate a large number of positive polarization charges at the interface of the channel layer 50 due to the large spontaneous polarization and piezoelectric polarization, the polarization positive charges can attract electrons, so as to form a two-dimensional electron gas on the surface of the channel layer 50 and the barrier layer 60, and further form a conductive channel.
[0030] Specifically, the donor contribution layer 30 can be a carbon-doped GaN layer or a carbon-doped AlGaN layer; the material of the high-resistance layer 40 can be a carbon-doped gallium nitride material, and the breakdown voltage of the device can be improved by increasing the carbon doping concentration; however, high-concentration carbon doping will generate high-concentration defect centers in the high-resistance layer, thereby causing the phenomenon of resistance drift, that is, the dynamic resistance characteristics of the device are weakened; in gallium nitride heteroepitaxy, a high dislocation density will inevitably occur, usually on the order of 10 9 / cm 2 , and the carbon concentration in the high-resistance layer 40 is relatively high, which will cause the crystal quality to deteriorate on the one hand and introduce many defect energy levels on the other hand, and the defect energy levels are mainly acceptor energy levels.
[0031] The donor contribution layer 30 is used to provide donor atoms for the high-resistance layer 40, and the donor contribution layer 30 is weak N-type; if the donor contribution layer 30 is arranged between the channel layer 50 and the high-resistance layer 40, it will cause the lateral leakage current of the device to increase, especially in high-temperature application scenarios, thereby causing the vertical breakdown voltage of the device to decrease, and in addition, in a high-voltage application scenario, the device is more likely to burn out. Therefore, by arranging the donor contribution layer 30 between the buffer layer 20 and the high-resistance layer 40, the carbon doping concentration of the donor contribution layer 30 is less than the carbon doping concentration of the buffer layer 20, and the carbon doping concentration of the donor contribution layer 30 is less than the carbon doping concentration of the high-resistance layer 40, on the one hand, the crystal quality of the entire epitaxial structure can be improved, and on the other hand, the donor contribution layer 30 can be used to provide more donors without increasing the leakage current of the device, which can be combined with the acceptors in the high-resistance layer 40 and the buffer layer 20 to compensate for the acceptor impurities in the high-resistance layer 40 and the buffer layer 20, and improve the defect centers caused by the high carbon doping concentration of the high-resistance layer 40 and the buffer layer 20, thereby improving the phenomenon of resistance drift.
[0032] The power device provided by the technical scheme of the embodiment of the utility model includes: the substrate 10, the buffer layer 20, the donor contribution layer 30, the high resistance layer 40, the channel layer 50 and the barrier layer 60 are sequentially stacked; the donor contribution layer 30 is used to provide donor atoms for the high-resistance layer. The donor contribution layer 30 provided by the embodiment of the utility model can improve the crystal quality of the entire epitaxial structure, and on the other hand, the donor contribution layer 30 is used to provide more donor atoms, compensate for the acceptor impurities in the high-resistance layer 40 and the buffer layer 20, improve the defect centers caused by the high carbon doping concentration of the high-resistance layer 40 and the buffer layer 20, and thereby improve the phenomenon of resistance drift.
[0033] Optionally, referring to Figure 1 , the carbon doping concentration of the donor contribution layer 30 is less than the carbon doping concentration of the buffer layer 20, and the carbon doping concentration of the donor contribution layer 30 is less than the carbon doping concentration of the high-resistance layer 40.
[0034] Among them, Figure 2It is a schematic diagram of atomic concentration changing with device depth provided by the embodiment of the utility model, reference Figure 2 , abscissa is device depth, device depth is the depth size of device along the direction of substrate 10 pointing to barrier layer 60, unit is nm, and the origin indicates the surface of power device farthest from substrate 10;Atomic concentration is ordinate, left ordinate indicates the concentration of gallium (Ga) atom, mainly to calibrate the content of Ga in material, and right ordinate is the concentration of carbon (C), to distinguish the difference of carbon atom content in channel layer 50, high resistance layer 40, donor contribution layer 30 and buffer layer 20.Through setting donor contribution layer 30 between high resistance layer 40 and buffer layer, setting the carbon doping concentration of donor contribution layer 30 less than the carbon doping concentration of buffer layer 20, the carbon doping concentration can be gradually reduced, and the crystal quality of the whole epitaxial structure can be improved in the epitaxial process;The carbon doping concentration of donor contribution layer 30 is less than the carbon doping concentration of high resistance layer 40, so that donor contribution layer 30 can be used to provide more donors without increasing device leakage current, can be combined with acceptor in high resistance layer 40 and buffer layer 20, compensate acceptor impurities in high resistance layer 40 and buffer layer 20, improve the defect center caused by high carbon doping concentration of high resistance layer 40 and buffer layer 20, so as to improve the phenomenon of resistance deviation.
[0035] Optionally, reference Figure 1 And Figure 2 The carbon doping concentration of donor contribution layer 30 ranges from 10 16 / cm 3 to 10 19 / cm 3 .
[0036] Among them, the depth range of donor contribution layer 30 in power device is between 800nm-1000nm, the carbon doping concentration of donor contribution layer 30 ranges from 10 16 / cm 3 to 10 19 / cm 3 by controlling different growth conditions;Different growth conditions can be different pressure and / or temperature, etc., according to actual demand to set the carbon doping concentration of donor contribution layer 30, which can improve the crystal quality of the whole epitaxial structure, and can also improve the defect center caused by high carbon doping concentration of high resistance layer 40 and buffer layer 20, so as to improve the phenomenon of resistance deviation.
[0037] Optionally, reference Figure 1 The thickness of donor contribution layer 30 ranges from 50nm to 300nm.
[0038] The donor contribution layer 30 can be formed by using a chemical vapor deposition method (MOCVD) or a molecular beam epitaxy (MBE), the amount of carbon doping is regulated by adjusting the epitaxial growth conditions such as temperature, air pressure and growth rate, the thickness of the donor contribution layer 30 ranges from 50 nm to 300 nm, the crystal quality of the epitaxial structure is improved, more donor atoms are provided, and the resistance shift phenomenon is improved.
[0039] Optionally, Figure 3 is a structural schematic diagram of another power device provided by the utility model, referring to Figure 3 , the power device further comprises: a nucleation layer 70; the nucleation layer 70 is located between the substrate 10 and the buffer layer 20.
[0040] The nucleation layer 70 covers the substrate 10, and the buffer layer 20 covers the nucleation layer 70; the material of the nucleation layer 70 can be aluminum nitride; the nucleation layer 70 provides nucleation sites for the growth of the buffer layer 20, and the crystal quality of the epitaxial structure can be improved.
[0041] Optionally, Figure 4 is a structural schematic diagram of another power device provided by the utility model, referring to Figure 4 , the power device further comprises: a spacer layer 80; the spacer layer 80 is located between the barrier layer 60 and the channel layer 50.
[0042] The spacer layer 80 covers the channel layer 50, and the barrier layer 60 covers the spacer layer 80; the material of the spacer layer 80 can be AlN; the spacer layer 80 can form a deep and narrow quantum well to improve the electron density of the channel, and can inhibit the penetration of two-dimensional electron gas into the barrier layer 60 to be subjected to alloy scattering, thereby improving the electron mobility.
[0043] Optionally, Figure 5 is a structural schematic diagram of another power device provided by the utility model, referring to Figure 5 , the power device further comprises: a cap layer 90; the cap layer 90 is located on the side, away from the channel layer 50, of the barrier layer 60.
[0044] The cap layer 90 covers the barrier layer 60; the material of the cap layer 90 can be P-type GaN; the cap layer 90 comprises a magnesium (Mg) doped GaN layer, which can be prepared by using a chemical vapor deposition method (MOCVD) or a molecular beam epitaxy (MBE); the cap layer 90 can be used to reduce current collapse and increase the breakdown voltage. Figure 2 The surface depth of the cap layer 90, away from the substrate 10, is 0 nm, and the surface depth of the substrate 10, away from the cap layer 90, is 1400 nm.
[0045] Optionally, referring to Figure 5The material of the nucleation layer 70 is the same as that of the spacer layer 80.
[0046] The material of the nucleation layer 70 is the same as that of the spacer layer 80, which can reduce the manufacturing cost.
[0047] Optionally, referring to Figure 5 The thickness of the channel layer 50 is 100-800 nm.
[0048] The thickness of the channel layer 50 is 100-800 nm, which has high crystal quality and is usually not doped to reduce the carrier concentration and reduce the drain current collapse caused by the trap effect.
[0049] Optionally, referring to Figure 5 The donor contribution layer 30 is a GaN layer or an AlGaN layer.
[0050] The donor contribution layer 30 covers the buffer layer 20, and the donor contribution layer 30 is a GaN layer or an AlGaN layer. The GaN layer can be pure gallium nitride material, and the AlGaN layer can be low-aluminum component aluminum gallium nitride material. This can improve the crystal quality of the entire epitaxial structure, and can also improve the defect centers caused by the high carbon doping concentration of the high resistance layer 40 and the buffer layer 20, thereby improving the resistance shift phenomenon.
[0051] It should be understood that the various forms of flow shown above can be used to reorder, add or delete steps. For example, the steps described in the present application can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solutions of the present application can be achieved, and the present application does not limit this.
[0052] The above specific embodiments do not constitute a limitation on the scope of protection of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement within the spirit and principles of the present application should be included in the scope of protection of the present application.
Claims
1. A power device, characterized by, Comprise: A substrate, a buffer layer, a donor contribution layer, a high resistance layer, a channel layer and a barrier layer are sequentially stacked; the donor contribution layer is used to provide donor atoms for the high resistance layer.
2. The power device of claim 1, wherein, The carbon doping concentration of the donor contribution layer is less than the carbon doping concentration of the buffer layer, and the carbon doping concentration of the donor contribution layer is less than the carbon doping concentration of the high resistance layer.
3. The power device of claim 1, wherein, The thickness of the donor contribution layer ranges from 50nm to 300nm.
4. The power device of claim 1, wherein, Also comprise: A nucleation layer; the nucleation layer is located between the substrate and the buffer layer.
5. The power device of claim 4, wherein, Also comprise: A spacer layer, the spacer layer is located between the barrier layer and the channel layer.
6. The power device of claim 1, wherein, Also comprise: A cap layer, the cap layer is located on the side of the barrier layer away from the channel layer.
7. The power device of claim 5, wherein, The material of the nucleation layer is the same as the material of the spacer layer.
8. The power device of claim 1, wherein, The thickness of the channel layer is 100nm-800nm.
9. The power device of claim 1, wherein, The donor contribution layer is a GaN layer or an AlGaN layer.