WO2021189923A1 - Hemt device having multi-metal gate structure and fabrication method therefor - Google Patents

Hemt device having multi-metal gate structure and fabrication method therefor Download PDF

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WO2021189923A1
WO2021189923A1 PCT/CN2020/132690 CN2020132690W WO2021189923A1 WO 2021189923 A1 WO2021189923 A1 WO 2021189923A1 CN 2020132690 W CN2020132690 W CN 2020132690W WO 2021189923 A1 WO2021189923 A1 WO 2021189923A1
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metal
layer
gate electrode
gate structure
gate
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Chinese (zh)
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王洪
高升
刘晓艺
胡文龙
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中山市华南理工大学现代产业技术研究院
华南理工大学
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
    • H01L29/76—Unipolar devices, e.g. field effect transistors
    • H01L29/772—Field effect transistors
    • H01L29/778—Field effect transistors with two-dimensional charge carrier gas channel, e.g. HEMT ; with two-dimensional charge-carrier layer formed at a heterojunction interface
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/40—Electrodes ; Multistep manufacturing processes therefor
    • H01L29/41—Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions
    • H01L29/423—Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions not carrying the current to be rectified, amplified or switched
    • H01L29/42312—Gate electrodes for field effect devices
    • H01L29/42316—Gate electrodes for field effect devices for field-effect transistors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/40—Electrodes ; Multistep manufacturing processes therefor
    • H01L29/43—Electrodes ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
    • H01L29/47—Schottky barrier electrodes
    • H01L29/475—Schottky barrier electrodes on AIII-BV compounds
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/66007—Multistep manufacturing processes
    • H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
    • H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
    • H01L29/66409—Unipolar field-effect transistors
    • H01L29/66446—Unipolar field-effect transistors with an active layer made of a group 13/15 material, e.g. group 13/15 velocity modulation transistor [VMT], group 13/15 negative resistance FET [NERFET]
    • H01L29/66462—Unipolar field-effect transistors with an active layer made of a group 13/15 material, e.g. group 13/15 velocity modulation transistor [VMT], group 13/15 negative resistance FET [NERFET] with a heterojunction interface channel or gate, e.g. HFET, HIGFET, SISFET, HJFET, HEMT

Definitions

  • the invention relates to the field of semiconductors, and in particular to a HEMT device with a multi-metal gate structure and a preparation method thereof.
  • GaN materials are widely used in high-frequency power amplifiers and high-voltage power switches because of their high electron mobility, low on-resistance, excellent heat dissipation capability, and high breakdown characteristics.
  • the breakdown voltage of GaN-based HEMT devices is far from reaching the theoretical limit value of GaN materials (3.4 MV/cm), and devices are often prone to breakdown between the gate and drain. How to reduce the height of the gate edge near the drain side The peak value of the electric field will help increase the breakdown voltage of the device.
  • the most common method is to use a gate field plate or a source field plate to adjust the electric field distribution, thereby reducing the high electric field peak at the edge of the gate close to the drain side.
  • the current metal deposition equipment is generally electron beam evaporation or magnetron sputtering.
  • Magnetron sputtering equipment mainly relies on argon ions to bombard the target material to sputter the atoms of the material onto the surface of the wafer; while the electron beam evaporation equipment mainly relies on heating to melt the material. After reaching the boiling point, the particles of the material will become one by one. Detach from the surface of the material to reach the surface of the wafer.
  • the sputtering distance is short, mainly related to the collision between particles.
  • the double-layer gate metal process helps to improve the breakdown voltage and dynamic performance of the device.
  • the above-mentioned method of changing the angle of electron beam deposition is difficult to accurately control and has poor repeatability.
  • the present invention proposes a HEMT device with a multi-metal gate structure.
  • the second layer of metal Y prepared by magnetron sputtering completely wraps the first layer of metal X prepared by electron beam, forming a YXY metal gate structure, and adjusting the electric field Distribution, which reduces the electric field peak value near the gate edge of the drain and improves the breakdown voltage of the device; at the same time, the lower electric field peak value of the gate edge weakens the gate injection electrons to form a virtual gate current to the device The impact of collapse improves the dynamic performance of the device.
  • the present invention provides a HEMT device with a multi-metal gate structure.
  • the device includes an AlGaN/GaN epitaxy. Both ends of the upper surface of the AlGaN/GaN epitaxy are respectively connected to source and drain electrodes.
  • the source and drain electrodes are provided with gate electrodes close to the source side.
  • the first layer of metal X of the gate electrode is deposited by electron beam evaporation
  • the second layer of metal Y of the gate electrode is deposited by magnetron sputtering
  • the work function of the second layer of metal Y of the gate electrode is higher than that of the first layer.
  • the work function of the metal X does not require an additional photolithography step, and the metal structure in contact with the (Al)GaN formed after the gate electrode is stripped is Y/X/Y.
  • the invention adopts the method of combining electron beam and magnetron sputtering, and realizes the multi-metal grid structure Y/X/Y after metal stripping.
  • the method does not need to change the electron beam deposition angle, and only the electron beam and magnetron sputtering
  • the traditional deposition method is repeatable, and compared with the above-mentioned double-layer gate metal process, the method based on the present invention achieves a three-layer gate metal process.
  • the HEMT device with a multi-metal gate structure includes: AlGaN/GaN epitaxy, source and drain electrodes, and gate electrodes; both ends of the upper surface of the AlGaN/GaN epitaxy are respectively connected to source and drain electrodes; the gate electrode and AlGaN /GaN epitaxial upper surface connection; the gate electrode includes a first layer of metal X and a second layer of metal Y; the metal structure formed after the gate electrode is stripped and in contact with (Al)GaN is Y/X/Y.
  • the HEMT device with a multi-metal gate structure provided by the present invention is an AlGaN/GaN HEMT device.
  • the length of the second layer of metal Y on both sides of the first layer of metal X is 0.5-1 ⁇ m.
  • the second layer of metal Y completely wraps the first layer of metal X.
  • the distance from the gate electrode to the source electrode is smaller than the distance from the gate electrode to the drain electrode, that is, the gate electrode is provided on the source-drain electrode side close to the source electrode.
  • the present invention provides a method for preparing the HEMT device with a multi-metal gate structure, which includes the following steps:
  • the photolithography window of the gate electrode in step (2) is designed to be 1-2 ⁇ m.
  • the first layer of metal X is deposited by electron beam evaporation, and the second layer of metal Y is deposited by magnetron sputtering; and the second layer of metal The thickness of Y is greater than the thickness of the first layer of metal X.
  • the first layer of metal X is one of Ni, Ti, TiN, etc.
  • the second layer of metal Y is of Cu, W, Ni, etc. kind of.
  • the present invention has the following beneficial effects and advantages:
  • the present invention uses electron beam and magnetron sputtering to prepare a multi-metal grid without additional photolithography steps.
  • the second layer of metal Y prepared by magnetron sputtering completely wraps the first layer of metal X prepared by electron beam to form
  • the virtual gate effect formed by electron injection into the gate is weakened.
  • the saturation capacitance (158pF) of the corresponding W/TiN/W structure device at the test frequency of 10KHz is compared with that of the TiN structure device ( 136pF) decreased by 13.9%, which improved the dynamic performance of the device.
  • FIG. 1 is a schematic diagram of an epitaxial layer of a GaN-based HEMT device before preparing source and drain contact electrodes according to an embodiment
  • FIG. 2 is a schematic diagram of the device structure after the source and drain contact electrodes are prepared and annealed to form an ohmic contact according to the embodiment;
  • FIG. 3 is a schematic diagram of the device structure after forming the gate electrode of the embodiment
  • Example 4 is a diagram of capacitance data of the HEMT device with a multi-metal gate structure and a device with a TiN structure prepared in Example 2;
  • This embodiment provides a HEMT device with a multi-metal gate structure.
  • a gate electrode 3 is provided on the pole 2 near the source side.
  • the first layer of metal Ti of the gate electrode 3 is deposited by electron beam evaporation, and the second layer of metal Ni of the gate electrode 3 is deposited by magnetron sputtering without additional light.
  • the metal structure in contact with the (Al)GaN formed after the gate electrode 3 is stripped is Ni/Ti/Ni.
  • G-1 represents the first layer of metal
  • G-2 represents the second layer of metal.
  • This embodiment also provides a method for preparing a HEMT device with a multi-metal gate structure, which includes the following steps:
  • the gate photolithography window of the HEMT device is designed to be 1 ⁇ m, and the metal structure Ni/Ti formed after the gate electrode is stripped /Ni, the length of the second layer of metal Ni on both sides of the first layer of metal Ti is 0.7 ⁇ m, the thickness of the first layer of metal Ti is 50 nm, the thickness of the second layer of metal Ni is 250 nm, and the second layer of metal Ni completely envelops the first layer of metal Ti to obtain the HEMT device with a multi-metal gate structure.
  • the HEMT device with a multi-metal gate structure prepared in Example 1 has good dynamic performance and low saturation capacitance, as shown in FIG. 4.
  • This embodiment provides a HEMT device with a multi-metal gate structure.
  • a gate electrode 3 is provided on the pole 2 near the source side.
  • the first layer of metal TiN of the gate electrode 3 is deposited by electron beam evaporation, and the second layer of metal W of the gate electrode 3 is deposited by magnetron sputtering without additional light.
  • the metal structure in contact with the (Al)GaN formed after the gate electrode 3 is stripped is W/TiN/W.
  • This embodiment also provides a method for preparing a HEMT device with a multi-metal gate structure, which includes the following steps:
  • Source and drain electrode windows on the AlGaN/GaN epitaxy prepare source and drain electrodes 2 and anneal to form ohmic contacts, as shown in Figure 2;
  • the gate photolithography window of the HEMT device is designed to be 1 ⁇ m, and the metal structure W/TiN formed after the gate electrode is stripped /W, the length of the second layer of metal W on both sides of the first layer of TiN is 0.5 ⁇ m, the thickness of the first layer of TiN is 50nm, the thickness of the second layer of metal W is 200nm, and the second layer of metal W is completely The first layer of metal TiN is wrapped to obtain the HEMT device with a multi-metal gate structure.
  • Figure 4 is a comparison diagram of CV characteristics of HEMT devices (W/TiN/W) with a multi-metal gate structure prepared in Example 2. It only shows the corresponding capacitance data when the test frequency is 10KHz. It can be seen that the W/ The saturation capacitance of the TiN/W structure device is lower than that of the TiN structure device.

Abstract

An HEMT device having a multi-metal gate structure and a fabrication method therefor. The device comprises an AlGaN/GaN epitaxial slice (1). Two ends of the upper surface of the AlGaN/GaN (1) epitaxial slice are respectively connected to source/drain electrodes (2), the side of the source/drain electrodes (2) close to the source electrode is provided with a gate electrode (3), a first layer metal X(G-1) of the gate electrode (3) is deposited by means of electron beam evaporation, a second layer metal Y(G-2) of the gate electrode (3) is deposited by means of magnetron sputtering, the work function of the second layer metal Y(G-2) of the gate electrode (3) is higher than the work function of the first layer metal X(G-1) of the gate electrode (3), and the metal structure formed after the gate electrode (3) is peeled off and in contact with AlGaN is Y/X/Y. The gate electrode (3) in contact with AlGaN is a multi-metal gate structure, which enables the electric field to be redistributed, lowers the electric field peak value at the edge of the gate electrode (3) close to the drain electrode, and increases the breakdown voltage of the device; meanwhile, the relatively low electric field peak value at the edge of the gate electrode (3) weakens the electron injection of the gate electrode (3) to create a virtual gate effect, which reduces the current collapse of the device and improves the dynamic performance of the device.

Description

具有多金属栅结构的HEMT器件及其制备方法HEMT device with multi-metal gate structure and preparation method thereof 技术领域Technical field
本发明涉及半导体领域，特别涉及具有多金属栅结构的HEMT器件及其制备方法。 The invention relates to the field of semiconductors, and in particular to a HEMT device with a multi-metal gate structure and a preparation method thereof.
背景技术Background technique
GaN材料因具有高电子迁移率、低导通电阻、优异的散热能力以及高击穿等特性，广泛应用于高频功率放大器与高压功率开关等场合。目前GaN基HEMT器件的击穿电压远远没有达到GaN材料的理论极限值（3.4 MV/cm）,器件往往容易在栅漏之间击穿，如何降低靠近漏极一侧的栅极边缘的高电场峰值将有益于提高器件的击穿电压。目前最常见的方法是采用栅极场板或者源极场板来调节电场分布，从而降低靠近漏极一侧的栅极边缘的高电场峰值。另一方面，由于栅极注入电子导致的虚栅效应加剧了对于器件电流崩塌的影响，使得器件在应力条件下表现出较差的性能。目前普遍采用钝化工艺来减小势垒层上的表面态，抑制电流崩塌（R. Hao, et al, IEEE Electron Device Lett.,2017, 38(11)）；采用场板工艺来调制电场，从而减小表面态的做法也有相关的报道（H. Hanawa, et al, IEEE International Reliability Physics Symposium Proceedings., 2013）。有学者（A. K. Visvkarma, et al, Semicond. Sci. Technol., 2019， 34(10)）通过改变电子束沉积的角度来实现双层栅极金属工艺，形成了Ni/(Al)GaN与Ti/(Al)GaN栅极双接触界面，改变了栅极边缘电场分布，提高了器件的击穿电压与动态性能。GaN materials are widely used in high-frequency power amplifiers and high-voltage power switches because of their high electron mobility, low on-resistance, excellent heat dissipation capability, and high breakdown characteristics. At present, the breakdown voltage of GaN-based HEMT devices is far from reaching the theoretical limit value of GaN materials (3.4 MV/cm), and devices are often prone to breakdown between the gate and drain. How to reduce the height of the gate edge near the drain side The peak value of the electric field will help increase the breakdown voltage of the device. At present, the most common method is to use a gate field plate or a source field plate to adjust the electric field distribution, thereby reducing the high electric field peak at the edge of the gate close to the drain side. On the other hand, the virtual gate effect caused by the injection of electrons into the gate aggravates the impact on the current collapse of the device, making the device exhibit poor performance under stress conditions. At present, passivation technology is commonly used to reduce the surface state on the barrier layer and suppress current collapse (R. Hao, et al, IEEE Electron Device Lett., 2017, 38(11)); the use of field plate technology to modulate the electric field to reduce the surface state has also been reported (H. Hanawa, et al. al, IEEE International Reliability Physics Symposium Proceedings., 2013). There are scholars (A. K. Visvkarma, et al, Semicond. Sci. Technol., 2019, 34(10)) By changing the angle of electron beam deposition to realize the double-layer gate metal process, Ni/(Al)GaN and Ti/(Al)GaN are formed The double-contact interface of the gate changes the electric field distribution at the edge of the gate and improves the breakdown voltage and dynamic performance of the device.
目前沉积金属的设备一般是电子束蒸发或者磁控溅射。磁控溅射设备主要是依靠氩离子轰击靶材，将材料的原子溅射出来至晶圆表面；而电子束蒸发设备主要是依靠加热，让材料融化，到达沸点后，材料的粒子一个个的脱离材料表面到达晶圆表面。对于磁控溅射设备而言，其溅射距离短，主要涉及到粒子之间的碰撞，有一个粒子运动的平均自由程要考虑，类似于一个点光源，各个粒子间角度大，因此溅射在晶圆表面上的材料的区域会比定义的光刻窗口要大；而电子束蒸发的腔体长，类似于平行的光源，金属材料会垂直的蒸发在晶圆表面上。The current metal deposition equipment is generally electron beam evaporation or magnetron sputtering. Magnetron sputtering equipment mainly relies on argon ions to bombard the target material to sputter the atoms of the material onto the surface of the wafer; while the electron beam evaporation equipment mainly relies on heating to melt the material. After reaching the boiling point, the particles of the material will become one by one. Detach from the surface of the material to reach the surface of the wafer. For magnetron sputtering equipment, the sputtering distance is short, mainly related to the collision between particles. There is a mean free path of particle motion to consider, similar to a point light source, the angle between each particle is large, so the sputtering The area of material on the wafer surface will be larger than the defined photolithography window; while the electron beam evaporation cavity is longer, similar to a parallel light source, and the metal material will evaporate vertically on the wafer surface.
综上所述，双层栅极金属工艺有助于改善器件的击穿电压和动态性能。但上述提到的改变电子束沉积的角度的方法很难精确控制，且重复性差。In summary, the double-layer gate metal process helps to improve the breakdown voltage and dynamic performance of the device. However, the above-mentioned method of changing the angle of electron beam deposition is difficult to accurately control and has poor repeatability.
技术解决方案Technical solutions
本发明提出了具有多金属栅结构的HEMT器件，利用磁控溅射制备的第二层金属Y完全包裹住了利用电子束制备的第一层金属X，形成了YXY金属栅结构，调节了电场分布，降低了靠近漏极的栅极边缘的电场峰值，提高了器件的击穿电压；与此同时，较低的栅极边缘的电场峰值减弱了栅极注入电子以形成虚栅对于器件的电流崩塌的影响，提高了器件的动态性能。The present invention proposes a HEMT device with a multi-metal gate structure. The second layer of metal Y prepared by magnetron sputtering completely wraps the first layer of metal X prepared by electron beam, forming a YXY metal gate structure, and adjusting the electric field Distribution, which reduces the electric field peak value near the gate edge of the drain and improves the breakdown voltage of the device; at the same time, the lower electric field peak value of the gate edge weakens the gate injection electrons to form a virtual gate current to the device The impact of collapse improves the dynamic performance of the device.
本发明的目的至少通过如下技术方案之一实现的。The purpose of the present invention is achieved by at least one of the following technical solutions.
本发明提供了具有多金属栅结构的HEMT器件，所述器件包括AlGaN/GaN外延，AlGaN/GaN外延上表面的两端分别连接源漏电极，所述源漏电极靠近源极侧设置栅电极，所述栅电极第一层金属X采用电子束蒸发方式沉积，所述栅电极第二层金属Y采用磁控溅射方式沉积，所述栅电极第二层金属Y的功函数高于第一层金属X的功函数，无需额外的光刻步骤，所述栅电极剥离后形成的与(Al)GaN接触的金属结构为Y/X/Y。The present invention provides a HEMT device with a multi-metal gate structure. The device includes an AlGaN/GaN epitaxy. Both ends of the upper surface of the AlGaN/GaN epitaxy are respectively connected to source and drain electrodes. The source and drain electrodes are provided with gate electrodes close to the source side. The first layer of metal X of the gate electrode is deposited by electron beam evaporation, the second layer of metal Y of the gate electrode is deposited by magnetron sputtering, and the work function of the second layer of metal Y of the gate electrode is higher than that of the first layer. The work function of the metal X does not require an additional photolithography step, and the metal structure in contact with the (Al)GaN formed after the gate electrode is stripped is Y/X/Y.
本发明采用电子束与磁控溅射相结合的方法，金属剥离后实现了多金属栅结构Y/X/Y，该方法不需要改变电子束沉积的角度，电子束与磁控溅射只需采用传统的沉积方式，具有可重复性，且相较于上述提到的双层栅极金属工艺，基于本发明的方法实现的是三层栅极金属工艺。The invention adopts the method of combining electron beam and magnetron sputtering, and realizes the multi-metal grid structure Y/X/Y after metal stripping. The method does not need to change the electron beam deposition angle, and only the electron beam and magnetron sputtering The traditional deposition method is repeatable, and compared with the above-mentioned double-layer gate metal process, the method based on the present invention achieves a three-layer gate metal process.
本发明提供的具有多金属栅结构的HEMT器件，包括：AlGaN/GaN外延、源漏电极及栅电极；所述AlGaN/GaN外延上表面的两端分别连接源漏电极；所述栅电极与AlGaN/GaN外延上表面连接；所述栅电极包含第一层金属X和第二层金属Y；所述栅电极剥离后形成的与(Al)GaN接触的金属结构为Y/X/Y。The HEMT device with a multi-metal gate structure provided by the present invention includes: AlGaN/GaN epitaxy, source and drain electrodes, and gate electrodes; both ends of the upper surface of the AlGaN/GaN epitaxy are respectively connected to source and drain electrodes; the gate electrode and AlGaN /GaN epitaxial upper surface connection; the gate electrode includes a first layer of metal X and a second layer of metal Y; the metal structure formed after the gate electrode is stripped and in contact with (Al)GaN is Y/X/Y.
本发明提供的具有多金属栅结构的HEMT器件是一种AlGaN/GaN HEMT器件。The HEMT device with a multi-metal gate structure provided by the present invention is an AlGaN/GaN HEMT device.
进一步地，所述第一层金属X两侧的第二层金属Y的长度为0.5-1 μm。Further, the length of the second layer of metal Y on both sides of the first layer of metal X is 0.5-1 μm.
进一步地，所述二层金属Y完全包裹住了第一层金属X。Further, the second layer of metal Y completely wraps the first layer of metal X.
进一步地，所述栅电极到源极的距离小于栅电极到漏极的距离，即所述源漏电极靠近源极侧设置栅电极。Further, the distance from the gate electrode to the source electrode is smaller than the distance from the gate electrode to the drain electrode, that is, the gate electrode is provided on the source-drain electrode side close to the source electrode.
本发明提供一种制备所述的具有多金属栅结构的HEMT器件的方法，包括如下步骤：The present invention provides a method for preparing the HEMT device with a multi-metal gate structure, which includes the following steps:
（1）在AlGaN/GaN外延上定义源漏电极窗口，制备源漏电极并进行退火形成欧姆接触；(1) Define the source and drain electrode windows on the AlGaN/GaN epitaxy, prepare the source and drain electrodes and perform annealing to form ohmic contacts;
（2）定义栅电极光刻窗口，制备多金属栅结构Y/X/Y，得到所述具有多金属栅结构的HEMT器件。(2) Define the gate electrode photolithography window, prepare the multi-metal gate structure Y/X/Y, and obtain the HEMT device with the multi-metal gate structure.
进一步地，步骤（2）所述栅电极的光刻窗口设计为1-2 μm。Further, the photolithography window of the gate electrode in step (2) is designed to be 1-2 μm.
进一步地，步骤（2）所述多金属栅结构Y/X/Y中，第一层金属X采用电子束蒸发方式沉积，第二层金属Y采用磁控溅射方式沉积；且第二层金属Y的厚度要大于第一层金属X的厚度。Further, in the multi-metal gate structure Y/X/Y in step (2), the first layer of metal X is deposited by electron beam evaporation, and the second layer of metal Y is deposited by magnetron sputtering; and the second layer of metal The thickness of Y is greater than the thickness of the first layer of metal X.
进一步地，步骤（2）所述多金属栅结构Y/X/Y中，第一层金属X为Ni、Ti、TiN等中的一种，第二层金属Y为Cu、W、Ni等中的一种。Further, in the multi-metal gate structure Y/X/Y in step (2), the first layer of metal X is one of Ni, Ti, TiN, etc., and the second layer of metal Y is of Cu, W, Ni, etc. Kind of.
有益效果Beneficial effect
和现有技术相比，本发明具有以下有益效果和优点：Compared with the prior art, the present invention has the following beneficial effects and advantages:
本发明利用电子束与磁控溅射制备的多金属栅极，无需额外的光刻步骤，磁控溅射制备的第二层金属Y完全包裹住了电子束制备的第一层金属X，形成了多金属栅结构Y/X/Y；调节了电场分布，降低了靠近漏极的栅极边缘的电场峰值，提高了器件的击穿电压；与此同时，较低的栅极边缘的电场峰值减弱了栅极注入电子以形成的虚栅效应，通过进行C-V特性的测试，在10KHz的测试频率下对应的W/TiN/W结构的器件的饱和电容（158pF）相较于TiN结构的器件（136pF）下降了13.9%，提高了器件的动态性能。The present invention uses electron beam and magnetron sputtering to prepare a multi-metal grid without additional photolithography steps. The second layer of metal Y prepared by magnetron sputtering completely wraps the first layer of metal X prepared by electron beam to form The multi-metal gate structure Y/X/Y; the electric field distribution is adjusted, the electric field peak value near the gate edge of the drain is reduced, and the breakdown voltage of the device is increased; at the same time, the electric field peak value of the gate edge is lower The virtual gate effect formed by electron injection into the gate is weakened. Through the CV characteristic test, the saturation capacitance (158pF) of the corresponding W/TiN/W structure device at the test frequency of 10KHz is compared with that of the TiN structure device ( 136pF) decreased by 13.9%, which improved the dynamic performance of the device.
附图说明Description of the drawings
图1为实施例的在制备源漏接触电极前GaN基 HEMT器件的外延层的示意图；FIG. 1 is a schematic diagram of an epitaxial layer of a GaN-based HEMT device before preparing source and drain contact electrodes according to an embodiment;
图2为实施例的在制备完源漏接触电极并进行退火形成欧姆接触后的器件结构示意图；2 is a schematic diagram of the device structure after the source and drain contact electrodes are prepared and annealed to form an ohmic contact according to the embodiment;
图3为实施例的形成栅电极后的器件结构示意图；3 is a schematic diagram of the device structure after forming the gate electrode of the embodiment;
图4为实施例2制备的具有多金属栅结构的HEMT器件与TiN结构的器件的电容数据图；4 is a diagram of capacitance data of the HEMT device with a multi-metal gate structure and a device with a TiN structure prepared in Example 2;
图中，AlGaN/GaN外延1，源漏电极2，栅电极3。In the figure, AlGaN/GaN epitaxy 1, source and drain electrodes 2, and gate electrodes 3.
本发明的实施方式Embodiments of the present invention
以下结合实例对本发明的具体实施作进一步说明，但本发明的实施和保护不限于此。需指出的是，以下若有未特别详细说明之过程，均是本领域技术人员可参照现有技术实现或理解的。The specific implementation of the present invention will be further described below in conjunction with examples, but the implementation and protection of the present invention are not limited to this. It should be pointed out that if there are processes that are not specifically described in detail below, those skilled in the art can implement or understand with reference to the prior art.
实施例1Example 1
本实施例提供了具有多金属栅结构的HEMT器件，如图3所示，所述器件包括AlGaN/GaN外延1，AlGaN/GaN外延上表面的两端分别连接源漏电极2，所述源漏电极2靠近源极侧设置栅电极3，所述栅电极3第一层金属Ti采用电子束蒸发方式沉积，所述栅电极3第二层金属Ni采用磁控溅射方式沉积，无需额外的光刻步骤，所述栅电极3剥离后形成的与(Al)GaN接触的金属结构为Ni/Ti/Ni。图3中的G-1表示第一层金属，G-2表示第二层金属。This embodiment provides a HEMT device with a multi-metal gate structure. As shown in FIG. A gate electrode 3 is provided on the pole 2 near the source side. The first layer of metal Ti of the gate electrode 3 is deposited by electron beam evaporation, and the second layer of metal Ni of the gate electrode 3 is deposited by magnetron sputtering without additional light. In the engraving step, the metal structure in contact with the (Al)GaN formed after the gate electrode 3 is stripped is Ni/Ti/Ni. In FIG. 3, G-1 represents the first layer of metal, and G-2 represents the second layer of metal.
本实施例还提供了制备具有多金属栅结构的HEMT器件的方法，包括以下步骤：This embodiment also provides a method for preparing a HEMT device with a multi-metal gate structure, which includes the following steps:
（1）在AlGaN/GaN外延（制备源漏接触电极前的外延层如图1所示）上1定义源漏电极窗口，制备源漏电极2并进行退火形成欧姆接触，如图2所示；(1) On the AlGaN/GaN epitaxy (the epitaxial layer before the source and drain contact electrodes is prepared as shown in Figure 1) 1 define the source and drain electrode windows, prepare the source and drain electrodes 2 and perform annealing to form ohmic contacts, as shown in Figure 2;
（2）定义栅电极3光刻窗口，制备多金属栅结构Ni/Ti/Ni，如图3所示；HEMT器件的栅极光刻窗口设计为1μm，栅电极剥离后形成的金属结构Ni/Ti/Ni中，第一层金属Ti两侧的第二层金属Ni的长度为0.7 μm，第一层金属Ti的厚度为50 nm，第二层金属Ni的厚度为250 nm，且第二层金属Ni完全包裹住了第一层金属Ti，得到所述具有多金属栅结构的HEMT器件。(2) Define the photolithography window of the gate electrode 3, and prepare the multi-metal gate structure Ni/Ti/Ni, as shown in Figure 3. The gate photolithography window of the HEMT device is designed to be 1μm, and the metal structure Ni/Ti formed after the gate electrode is stripped /Ni, the length of the second layer of metal Ni on both sides of the first layer of metal Ti is 0.7 μm, the thickness of the first layer of metal Ti is 50 nm, the thickness of the second layer of metal Ni is 250 nm, and the second layer of metal Ni completely envelops the first layer of metal Ti to obtain the HEMT device with a multi-metal gate structure.
实施例1制备的具有多金属栅结构的HEMT器件具有良好的动态性能及较低的饱和电容，可参照图4所示。The HEMT device with a multi-metal gate structure prepared in Example 1 has good dynamic performance and low saturation capacitance, as shown in FIG. 4.
实施例2Example 2
本实施例提供了具有多金属栅结构的HEMT器件，如图3所示，所述器件包括AlGaN/GaN外延1，AlGaN/GaN外延上表面的两端分别连接源漏电极2，所述源漏电极2靠近源极侧设置栅电极3，所述栅电极3第一层金属TiN采用电子束蒸发方式沉积，所述栅电极3第二层金属W采用磁控溅射方式沉积，无需额外的光刻步骤，所述栅电极3剥离后形成的与(Al)GaN接触的金属结构为W/TiN/W。This embodiment provides a HEMT device with a multi-metal gate structure. As shown in FIG. A gate electrode 3 is provided on the pole 2 near the source side. The first layer of metal TiN of the gate electrode 3 is deposited by electron beam evaporation, and the second layer of metal W of the gate electrode 3 is deposited by magnetron sputtering without additional light. In the engraving step, the metal structure in contact with the (Al)GaN formed after the gate electrode 3 is stripped is W/TiN/W.
本实施例还提供了制备具有多金属栅结构的HEMT器件的方法，包括以下步骤：This embodiment also provides a method for preparing a HEMT device with a multi-metal gate structure, which includes the following steps:
（1）在AlGaN/GaN外延上1定义源漏电极窗口，制备源漏电极2并进行退火形成欧姆接触，如图2所示；(1) Define source and drain electrode windows on the AlGaN/GaN epitaxy, prepare source and drain electrodes 2 and anneal to form ohmic contacts, as shown in Figure 2;
（2）定义栅电极3光刻窗口，制备多金属栅结构W/TiN/W，如图3所示；HEMT器件的栅极光刻窗口设计为1μm，栅电极剥离后形成的金属结构W/TiN/W中，第一层金属TiN两侧的第二层金属W的长度为0.5μm，第一层金属TiN的厚度为50nm，第二层金属W的厚度为200nm，且第二层金属W完全包裹住了第一层金属TiN，得到所述具有多金属栅结构的HEMT器件。(2) Define the photolithography window of the gate electrode 3, and prepare the multi-metal gate structure W/TiN/W, as shown in Figure 3. The gate photolithography window of the HEMT device is designed to be 1μm, and the metal structure W/TiN formed after the gate electrode is stripped /W, the length of the second layer of metal W on both sides of the first layer of TiN is 0.5μm, the thickness of the first layer of TiN is 50nm, the thickness of the second layer of metal W is 200nm, and the second layer of metal W is completely The first layer of metal TiN is wrapped to obtain the HEMT device with a multi-metal gate structure.
图4为实施例2制备的具有多金属栅结构的HEMT器件（W/TiN/W）的C-V特性比较图，仅展示了在测试频率为10KHz时对应的电容数据，可以看出，具有W/TiN/W结构的器件相较于TiN结构的器件的饱和电容值更低。Figure 4 is a comparison diagram of CV characteristics of HEMT devices (W/TiN/W) with a multi-metal gate structure prepared in Example 2. It only shows the corresponding capacitance data when the test frequency is 10KHz. It can be seen that the W/ The saturation capacitance of the TiN/W structure device is lower than that of the TiN structure device.
以上实施例仅为本发明较优的实施方式，仅用于解释本发明，而非限制本发明，本领域技术人员在未脱离本发明精神实质下所作的改变、替换、修饰等均应属于本发明的保护范围。The above examples are only preferred embodiments of the present invention, and are only used to explain the present invention, but not to limit the present invention. Changes, substitutions, modifications, etc. made by those skilled in the art without departing from the spirit of the present invention shall belong to the present invention. The scope of protection of the invention.

Claims (8)

  1. 具有多金属栅结构的HEMT器件,其特征在于，包括：AlGaN/GaN外延、源漏电极及栅电极；所述AlGaN/GaN外延上表面的两端分别连接源漏电极；所述栅电极与AlGaN/GaN外延上表面连接；所述栅电极包含第一层金属X和第二层金属Y；所述栅电极剥离后形成的与(Al)GaN接触的金属结构为Y/X/Y。A HEMT device with a multi-metal gate structure is characterized by comprising: AlGaN/GaN epitaxy, source and drain electrodes, and gate electrodes; both ends of the upper surface of the AlGaN/GaN epitaxy are connected to source and drain electrodes, respectively; the gate electrode and AlGaN /GaN epitaxial upper surface connection; the gate electrode includes a first layer of metal X and a second layer of metal Y; the metal structure formed after the gate electrode is stripped and in contact with (Al)GaN is Y/X/Y.
  2. 根据权利要求1所述的具有多金属栅结构的HEMT器件,其特征在于，所述第一层金属X两侧的第二层金属Y的长度为0.5-1 μm。The HEMT device with a multi-metal gate structure according to claim 1, wherein the length of the second layer of metal Y on both sides of the first layer of metal X is 0.5-1 μm.
  3. 根据权利要求1所述的具有多金属栅结构的HEMT器件,其特征在于，所述二层金属Y完全包裹住了第一层金属X。The HEMT device with a multi-metal gate structure according to claim 1, wherein the second layer of metal Y completely wraps the first layer of metal X.
  4. 根据权利要求1所述的具有多金属栅结构的HEMT器件,其特征在于，所述栅电极到源极的距离小于栅电极到漏极的距离。The HEMT device with a multi-metal gate structure according to claim 1, wherein the distance from the gate electrode to the source electrode is smaller than the distance from the gate electrode to the drain electrode.
  5. 一种制备权利要求1-4任一项所述的具有多金属栅结构的HEMT器件的方法，其特征在于，包括如下步骤：A method for preparing the HEMT device with a multi-metal gate structure according to any one of claims 1 to 4, characterized in that it comprises the following steps:
    （1）在AlGaN/GaN外延上定义源漏电极窗口，制备源漏电极并进行退火形成欧姆接触；(1) Define the source and drain electrode windows on the AlGaN/GaN epitaxy, prepare the source and drain electrodes and perform annealing to form ohmic contacts;
    （2）定义栅电极光刻窗口，制备多金属栅结构Y/X/Y，得到所述具有多金属栅结构的HEMT器件。(2) Define the gate electrode photolithography window, prepare the multi-metal gate structure Y/X/Y, and obtain the HEMT device with the multi-metal gate structure.
  6. 根据权利要求5所述的具有多金属栅结构的HEMT器件的制备方法,其特征在于，步骤（2）所述栅电极的光刻窗口设计为1-2 μm。The method for manufacturing a HEMT device with a multi-metal gate structure according to claim 5, wherein the photolithography window of the gate electrode in step (2) is designed to be 1-2 μm.
  7. 根据权利要求5所述的具有多金属栅结构的HEMT器件的制备方法,其特征在于，步骤（2）所述多金属栅结构Y/X/Y中，第一层金属X采用电子束蒸发方式沉积，第二层金属Y采用磁控溅射方式沉积；且第二层金属Y的厚度要大于第一层金属X的厚度。The method for manufacturing a HEMT device with a multi-metal gate structure according to claim 5, characterized in that, in the multi-metal gate structure Y/X/Y in step (2), the first layer of metal X adopts an electron beam evaporation method For deposition, the second layer of metal Y is deposited by magnetron sputtering; and the thickness of the second layer of metal Y is greater than the thickness of the first layer of metal X.
  8. 根据权利要求5所述的具有多金属栅结构的HEMT器件的制备方法,其特征在于，步骤（2）所述多金属栅结构Y/X/Y中，第一层金属X为Ni、Ti、TiN中的一种，第二层金属Y为Cu、W、Ni中的一种。The method for manufacturing a HEMT device with a multi-metal gate structure according to claim 5, characterized in that, in the multi-metal gate structure Y/X/Y in step (2), the first layer of metal X is Ni, Ti, One of TiN, and the second layer of metal Y is one of Cu, W, and Ni.
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