CN102856373B - High-electronic-mobility-rate transistor - Google Patents

Abstract

Translated fromChinese

本发明涉及微电子技术。本发明解决了现有高电子迁移率晶体管栅漏电流较大的问题，提供了一种高电子迁移率晶体管，其技术方案可概括为：高电子迁移率晶体管，包括栅极金属、源极金属、漏极金属、基底、缓冲层、沟道层及势垒层，其特征在于，所述基底上外延生长有插入层，插入层上外延生长有缓冲层，缓冲层上外延生长有沟道层，沟道层上外延生长有势垒层，势垒层上外延生长有盖帽层，栅极金属、源极金属及漏极金属分别位于盖帽层上，栅极金属与源极金属之间及栅极金属与漏极金属之间具有钝化层，钝化层与盖帽层相接触。本发明的有益效果是，提高器件的性能，适用于高电子迁移率晶体管。

The present invention relates to microelectronics technology. The present invention solves the problem of large gate leakage current of existing high electron mobility transistors, and provides a high electron mobility transistor. , a drain metal, a base, a buffer layer, a channel layer, and a barrier layer, wherein an insertion layer is epitaxially grown on the base, a buffer layer is epitaxially grown on the insertion layer, and a channel layer is epitaxially grown on the buffer layer , a barrier layer is epitaxially grown on the channel layer, and a capping layer is epitaxially grown on the barrier layer. The gate metal, source metal, and drain metal are respectively located on the capping layer. There is a passivation layer between the electrode metal and the drain metal, and the passivation layer is in contact with the capping layer. The invention has the beneficial effects of improving the performance of the device and being suitable for high electron mobility transistors.

Description

Translated fromChinese

高电子迁移率晶体管High Electron Mobility Transistor

技术领域technical field

本发明涉及微电子技术，特别涉及高电子迁移率晶体管。The present invention relates to microelectronics technology, in particular to high electron mobility transistors.

背景技术Background technique

氮化镓与第一代和第二代半导体材料相比具有更优良的电学性能，它是一种宽带隙半导体材料，具有高的击穿电场强度、高饱和速度及高热稳定性等，由于氮化镓材料的优良性能，使得其得到了人们的极大关注和研究，其中研究最为广泛的是AlGaN/GaN高电子迁移率晶体管（HEMT），该器件在高频、高功率、高温等都有应用.Compared with the first and second generation semiconductor materials, gallium nitride has better electrical properties. It is a wide bandgap semiconductor material with high breakdown electric field strength, high saturation velocity and high thermal stability. Due to nitrogen The excellent performance of GaN materials has attracted great attention and research. Among them, the most widely studied is AlGaN/GaN High Electron Mobility Transistor (HEMT), which has high frequency, high power, high temperature, etc. application.

AlGaN/GaN高电子迁移率晶体管是一种异质结场效应晶体管，它是利用具有很高迁移率的二维电子气（2-DEG）而工作的。2-DEG存在于AlGaN势垒层和GaN沟道层相接触的异质结表面，其迁移率很高并且在极低的温度下也不冻结，具有很好的温度特性。HEMT是一种电压控制的器件，栅极电压Vg可以控制AlGaN和GaN异质结势阱的深度，进而控制势阱中2-DEG的面密度，从而控制器件的工作电流。2-DEG是由于极化作用产生的，而氮化物具有很强的极化效应。极化效应包括压电极化和自发极化，AlGaN/GaN异质结中的压电极化效应是AlGaAs/GaAs异质结的5倍，在纤锌矿结构Ⅲ族氮化物中自发极化也比较大，所以AlGaN/GaNHEMT得到了广泛的研究。目前高电子迁移率晶体管结构示意图如图1所示，其栅漏电流较大。AlGaN/GaN HEMT器件是当前研究的热点。AlGaN/GaN high electron mobility transistor is a heterojunction field effect transistor, which works by using two-dimensional electron gas (2-DEG) with high mobility. 2-DEG exists on the surface of the heterojunction where the AlGaN barrier layer and the GaN channel layer are in contact. It has high mobility and does not freeze at extremely low temperatures, and has good temperature characteristics. HEMT is a voltage-controlled device. The gate voltage Vg can control the depth of AlGaN and GaN heterojunction potential wells, and then control the surface density of 2-DEG in the potential wells, thereby controlling the operating current of the device. 2-DEG is generated due to polarization, and nitrides have a strong polarization effect. The polarization effect includes piezoelectric polarization and spontaneous polarization. The piezoelectric polarization effect in the AlGaN/GaN heterojunction is 5 times that of the AlGaAs/GaAs heterojunction, and the spontaneous polarization in the wurtzite structure group III nitride It is also relatively large, so AlGaN/GaN HEMTs have been extensively studied. The schematic diagram of the current high electron mobility transistor structure is shown in FIG. 1 , and its gate leakage current is relatively large. AlGaN/GaN HEMT devices are the hotspot of current research.

发明内容Contents of the invention

本发明的目的是克服目前高电子迁移率晶体管栅漏电流较大的缺点，提供一种高电子迁移率晶体管。The purpose of the present invention is to overcome the disadvantage of large gate leakage current of current high electron mobility transistors and provide a high electron mobility transistor.

本发明解决其技术问题，采用的技术方案是，高电子迁移率晶体管，包括栅极金属、源极金属、漏极金属、基底、缓冲层、沟道层及势垒层，其特征在于，所述基底上外延生长有插入层，插入层上外延生长有缓冲层，缓冲层上外延生长有沟道层，沟道层上外延生长有势垒层，势垒层上外延生长有盖帽层，栅极金属、源极金属及漏极金属分别位于盖帽层上，栅极金属与源极金属之间及栅极金属与漏极金属之间具有钝化层，钝化层与盖帽层相接触。The present invention solves its technical problem, and the technical solution adopted is that the high electron mobility transistor includes a gate metal, a source metal, a drain metal, a substrate, a buffer layer, a channel layer and a barrier layer, and is characterized in that the An insertion layer is epitaxially grown on the substrate, a buffer layer is epitaxially grown on the insertion layer, a channel layer is epitaxially grown on the buffer layer, a barrier layer is epitaxially grown on the channel layer, a cap layer is epitaxially grown on the barrier layer, and a gate layer is epitaxially grown on the barrier layer. The electrode metal, the source metal and the drain metal are respectively located on the capping layer, and there is a passivation layer between the gate metal and the source metal and between the gate metal and the drain metal, and the passivation layer is in contact with the capping layer.

具体的，所述基底为碳化硅材料，所述插入层为氮化铝材料，其厚度为3nm，所述缓冲层为掺杂的氮化镓材料，其厚度为3μm，所述沟道层为氮化镓材料，其厚度为80nm，所述势垒层为AlGaN材料，其厚度为30nm，Al（即铝）的组分为0.3，所述盖帽层为氮化镓材料，厚度为5nm，掺杂浓度为1×10¹⁸cm^-3到5×10¹⁸cm^-3之间，所述钝化层为氮化硅材料，厚度为0.12μm。Specifically, the substrate is silicon carbide material, the insertion layer is aluminum nitride material with a thickness of 3 nm, the buffer layer is doped gallium nitride material with a thickness of 3 μm, and the channel layer is Gallium nitride material with a thickness of 80nm, the barrier layer is AlGaN material with a thickness of 30nm, the composition of Al (namely aluminum) is 0.3, the capping layer is gallium nitride material with a thickness of 5nm, doped The impurity concentration is between 1×10¹⁸ cm^-3 and 5×10¹⁸ cm^-3 , and the passivation layer is made of silicon nitride with a thickness of 0.12 μm.

进一步的，所述栅极金属是金，与氮化镓盖帽层形成肖特基接触，源极金属及漏极金属为镍，与氮化镓盖帽层形成欧姆接触。Further, the gate metal is gold, which forms a Schottky contact with the gallium nitride cap layer, and the source metal and drain metal are nickel, which form an ohmic contact with the gallium nitride cap layer.

本发明的有益效果是，上述高电子迁移率晶体管，通过改变器件的外延结构和各层结构相关参数的优化，使得器件在工作时跨导很大并且在栅极电压工作的一定范围内跨导的变化很小，也就是器件具有较好的压控能力和较高的线性度。The beneficial effect of the present invention is that the above-mentioned high electron mobility transistor, by changing the epitaxial structure of the device and optimizing the relevant parameters of each layer structure, makes the device have a large transconductance during operation and a transconductance within a certain range of gate voltage operation. The change is very small, that is, the device has better voltage control capability and higher linearity.

附图说明Description of drawings

图1为现有技术中高电子迁移率晶体管结构示意图；FIG. 1 is a schematic structural diagram of a high electron mobility transistor in the prior art;

图2为本发明实施例的高电子迁移率晶体管结构示意图；2 is a schematic structural diagram of a high electron mobility transistor according to an embodiment of the present invention;

图3为本发明实施例盖帽层在不同掺杂浓度下的高电子迁移率晶体管的跨导变化示意图。FIG. 3 is a schematic diagram of the transconductance variation of the high electron mobility transistor with the cap layer under different doping concentrations according to the embodiment of the present invention.

具体实施方式Detailed ways

下面结合附图及实施例，详细描述本发明的技术方案。The technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

本发明所述的高电子迁移率晶体管，包括栅极金属、源极金属、漏极金属及基底，基底上外延生长有插入层，插入层上外延生长有缓冲层，缓冲层上外延生长有沟道层，沟道层上外延生长有势垒层，势垒层上外延生长有盖帽层，栅极金属、源极金属及漏极金属分别位于盖帽层上，栅极金属与源极金属之间及栅极金属与漏极金属之间具有钝化层，钝化层与盖帽层相接触。The high electron mobility transistor described in the present invention comprises a gate metal, a source metal, a drain metal and a substrate, an insertion layer is epitaxially grown on the substrate, a buffer layer is epitaxially grown on the insertion layer, and a trench is epitaxially grown on the buffer layer A barrier layer is epitaxially grown on the channel layer, and a capping layer is epitaxially grown on the barrier layer. The gate metal, source metal and drain metal are respectively located on the capping layer, between the gate metal and the source metal And there is a passivation layer between the gate metal and the drain metal, and the passivation layer is in contact with the capping layer.

实施例Example

本例的基底为碳化硅材料，所述插入层为氮化铝材料，其厚度为3nm，缓冲层为掺杂的氮化镓材料，其厚度为3μm，沟道层为氮化镓材料，其厚度为80nm，势垒层为AlGaN材料，其厚度为30nm，Al（即铝）的组分为0.3，盖帽层为氮化镓材料，厚度为5nm，掺杂浓度在1×10¹⁸cm^-3到5×10¹⁸cm^-3之间变化，结果显示在一定范围内盖帽层浓度越大跨导越大，但是当盖帽层浓度超过1×10²⁰cm^-3时跨导反而减小，本实施例中盖帽层在不同掺杂浓度下的高电子迁移率晶体管的跨导变化示意图如图3所示，GaN盖帽层的浓度对跨导有较大的影响，钝化层为氮化硅材料，厚度为0.12μm，本实施例的高电子迁移率晶体管结构示意图如图2。The substrate in this example is silicon carbide material, the insertion layer is aluminum nitride material with a thickness of 3 nm, the buffer layer is doped gallium nitride material with a thickness of 3 μm, and the channel layer is gallium nitride material with a thickness of 3 nm. The thickness is 80nm, the barrier layer is made of AlGaN material, its thickness is 30nm, the composition of Al (namely aluminum) is 0.3, the cap layer is made of gallium nitride material, the thickness is 5nm, and the doping concentration is 1×10¹⁸ cm^-3 to 5×10¹⁸ cm^-3 , the results show that within a certain range, the greater the concentration of the capping layer, the greater the transconductance, but when the concentration of the capping layer exceeds 1×10²⁰ cm^-3 , the transconductance decreases instead. The schematic diagram of the transconductance change of the high electron mobility transistor under different doping concentrations of the capping layer in the example is shown in Figure 3. The concentration of the GaN capping layer has a great influence on the transconductance, and the passivation layer is made of silicon nitride. The thickness is 0.12 μm. The schematic diagram of the structure of the high electron mobility transistor in this embodiment is shown in FIG. 2 .

首先在碳化硅材料制成的基底上外延生长3nm厚度的氮化铝插入层，再在氮化铝插入层插入层上外延生长3μm厚度的缓冲层，缓冲层为掺杂的氮化镓材料，缓冲层上再外延生长80nm厚度的氮化镓沟道层，氮化镓沟道层上外延生长30nm厚度的AlGaN势垒层，AlGaN势垒层中，Al（即铝）的组分为0.3，AlGaN势垒层上外延生长5nm厚度的氮化镓盖帽层，栅极金属、源极金属及漏极金属分别位于氮化镓盖帽层上，栅极金属与源极金属之间及栅极金属与漏极金属之间具有0.12μm厚度的氮化硅钝化层，氮化硅钝化层与氮化镓盖帽层相接触，栅极金属为金，与氮化镓盖帽层形成肖特基接触，源极金属及漏极金属为镍，与氮化镓盖帽层形成欧姆接触。First, epitaxially grow a 3nm-thick aluminum nitride insertion layer on a substrate made of silicon carbide material, and then epitaxially grow a 3μm-thick buffer layer on the aluminum nitride insertion layer insertion layer, the buffer layer is a doped gallium nitride material, On the buffer layer, a gallium nitride channel layer with a thickness of 80nm is epitaxially grown, and an AlGaN barrier layer with a thickness of 30nm is epitaxially grown on the gallium nitride channel layer. In the AlGaN barrier layer, the composition of Al (namely aluminum) is 0.3, On the AlGaN barrier layer, a gallium nitride cap layer with a thickness of 5nm is epitaxially grown. The gate metal, source metal and drain metal are respectively located on the gallium nitride cap layer, between the gate metal and the source metal and between the gate metal and the gate metal. There is a silicon nitride passivation layer with a thickness of 0.12 μm between the drain metals, the silicon nitride passivation layer is in contact with the gallium nitride capping layer, the gate metal is gold, and forms a Schottky contact with the gallium nitride capping layer, The source metal and the drain metal are nickel, which form ohmic contact with the GaN capping layer.

掺杂浓度较高的GaN盖帽层增加了2-DEG的浓度，进而使AlGaN/GaN HEMT器件表现出更优的性能，而Si₃N₄钝化层保护着HEMT器件表面不受外界杂质影响，同时还起到固定表面离子的作用，进而提高器件的性能。而GaN盖帽层可以降低栅漏电流及提高器件的击穿特性，所以本发明电性能更具优势。且由于HEMT是电压控制器件，栅极电压可以控制异质结势阱的深度，也可以控制势阱中2-DEG的面密度，从而控制器件的工作电流；而跨导的大小反映了栅源电压对栅极电流的控制作用，所以跨导大表明了器件的压控能力强。The GaN capping layer with higher doping concentration increases the concentration of 2-DEG, which makes the AlGaN/GaN HEMT device exhibit better performance, while the Si₃ N₄ passivation layer protects the surface of the HEMT device from external impurities, At the same time, it also plays the role of fixing surface ions, thereby improving the performance of the device. The GaN capping layer can reduce the gate leakage current and improve the breakdown characteristics of the device, so the electrical performance of the present invention has more advantages. And because HEMT is a voltage-controlled device, the gate voltage can control the depth of the heterojunction potential well, and can also control the surface density of 2-DEG in the potential well, thereby controlling the operating current of the device; and the size of the transconductance reflects the gate-source The control effect of the voltage on the gate current, so the large transconductance indicates that the device has a strong voltage control ability.

Claims (2)

Translated fromChinese

1.高电子迁移率晶体管，包括栅极金属、源极金属、漏极金属、基底、缓冲层、沟道层及势垒层，其特征在于，所述基底上外延生长有插入层，插入层上外延生长有缓冲层，缓冲层上外延生长有沟道层，沟道层上外延生长有势垒层，势垒层上外延生长有盖帽层，栅极金属、源极金属及漏极金属分别位于盖帽层上，栅极金属与源极金属之间及栅极金属与漏极金属之间具有钝化层，钝化层与盖帽层相接触，1. High electron mobility transistor, comprising gate metal, source metal, drain metal, substrate, buffer layer, channel layer and potential barrier layer, it is characterized in that, epitaxial growth has insertion layer on described substrate, insertion layer A buffer layer is epitaxially grown on the buffer layer, a channel layer is epitaxially grown on the buffer layer, a barrier layer is epitaxially grown on the channel layer, a cap layer is epitaxially grown on the barrier layer, and the gate metal, source metal and drain metal are respectively Located on the capping layer, there is a passivation layer between the gate metal and the source metal and between the gate metal and the drain metal, and the passivation layer is in contact with the capping layer,所述基底为碳化硅材料，所述插入层为氮化铝材料，其厚度为3nm，所述缓冲层为掺杂的氮化镓材料，其厚度为3μm，所述沟道层为氮化镓材料，其厚度为80nm，所述势垒层为AlGaN材料，其厚度为30nm，Al(即铝)的组分为0.3，所述盖帽层为氮化镓材料，厚度为5nm，掺杂浓度为1×10¹⁸cm^-3到5×10¹⁸cm^-3之间，所述钝化层为氮化硅材料，厚度为0.12μm。The substrate is silicon carbide material, the insertion layer is aluminum nitride material with a thickness of 3 nm, the buffer layer is doped gallium nitride material with a thickness of 3 μm, and the channel layer is gallium nitride material Material, its thickness is 80nm, described potential barrier layer is AlGaN material, and its thickness is 30nm, and the composition of Al (being aluminum) is 0.3, and described capping layer is gallium nitride material, and thickness is 5nm, and doping concentration is Between 1×10¹⁸ cm⁻³ and 5×10¹⁸ cm⁻³ , the passivation layer is made of silicon nitride material with a thickness of 0.12 μm.2.根据权利要求1所述高电子迁移率晶体管，其特征在于，所述栅极金属是金，与氮化镓盖帽层形成肖特基接触，源极金属及漏极金属为镍，与氮化镓盖帽层形成欧姆接触。2. The high electron mobility transistor according to claim 1, wherein the gate metal is gold, which forms a Schottky contact with the gallium nitride capping layer, and the source metal and the drain metal are nickel, which are connected with nitrogen The GaN capping layer forms an ohmic contact.