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Schottky contact system applicable to AlGaN/GaN high electron mobility transistor (HEMT)

Active Publication Date: 2017-12-26
NO 55 INST CHINA ELECTRONIC SCI & TECHNOLOGYGROUP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

When multi-layer metal systems such as Ni / Au / Ti or Ni / Pt / Au / Pt / Ti or Ni / Pt / Au / Ni or Pt / Au / Pt / Ti are used as the Schottky gate of AlGaN / GaN HEMT devices, due to The thickness of the Ni metal layer or Ni / Pt or Pt metal layer is generally about 30-50nm due to its high stress, which makes the Au metal layer on it closer to the epitaxial layer of the AlGaN / GaN HEMT device, and the Au metal layer and AlGaN There is a large thermal mismatch in the epitaxial layer of GaN HEMT devices, which makes the devices have reliability risks when they work at high temperatures
In the semiconductor process, in the multi-layer metal system that can be used as the Schottky gate of AlGaN / GaN HEMT devices, in addition to Au can play a role in reducing the gate resistance of the device, Al or Cu can also be used, but whether it is Au or Al Or Cu, their thermal expansion coefficients are large, and there is a large thermal mismatch with the epitaxial layer of AlGaN / GaN HEMT devices, which is not conducive to the manufacture of high-reliability AlGaN / GaN HEMT devices, so it needs to be improved to reduce Au or GaN HEMT Is it the influence of Al or Cu metals?

Method used

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  • Schottky contact system applicable to AlGaN/GaN high electron mobility transistor (HEMT)
  • Schottky contact system applicable to AlGaN/GaN high electron mobility transistor (HEMT)
  • Schottky contact system applicable to AlGaN/GaN high electron mobility transistor (HEMT)

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Embodiment 1

[0024] Figure 2A-Figure 2EIt is a schematic diagram of the implementation steps of this embodiment, Figure 2A It is a schematic diagram of the general structure of epitaxial materials used in AlGaN / GaN HEMT, including a substrate 31 , a GaN buffer layer 32 and an AlGaN barrier layer 33 . Regarding the materials used for the substrate 31 in the AlGaN / GaN HEMT, the formation of the GaN buffer layer 32 and the AlGaN barrier layer 33 can refer to relevant literature reports; in addition Figure 2A The one in is the general structural diagram of the epitaxial material used in AlGaN / GaN HEMT, indicating that there are other forms of epitaxial material structures. For other structural forms, please refer to relevant literature, and no further description will be given.

[0025] Such as Figure 2B As shown, an ohmic contact electrode is provided on the AlGaN barrier layer 33 as the source electrode 34 , and the ohmic contact electrode is used as the drain electrode 35 , and the di...

Embodiment 2

[0030] Figure 3A-Figure 3B It is a schematic diagram of the experimental steps of this embodiment. Regarding the formation of the materials used for the substrate 31 in the AlGaN / GaN HEMT, the GaN buffer layer 32 and the AlGaN barrier layer 33, please refer to relevant literature reports; regarding the production of the source electrode 34 and the drain electrode 35 Reference may be made to the description in Embodiment 1, and details are not repeated here. Such as Figure 3A As shown, after the source electrode 34 and the drain electrode 35 are completed, the photoresist layer 46 is coated, and after exposure, development and other processes, a "T"-shaped groove 47 is formed in the resist layer 46. In order to obtain a "T"-shaped concave The groove 47 and the photoresist layer 46 generally need to be composed of two different photoresist layers, and are obtained through at least two exposures and one or two developments. How to obtain the "T" groove 47 is well known in the ...

Embodiment 3

[0033] Using the same process as in Example 1 or 2 to prepare the Schottky gate electrode, the gate electrode is preferably deposited by evaporation Ni / Mo / Ti / Pt / Y / Ti / Ni / Mo / Ti / Pt / Y / Ti A multilayer metal system in the form of Ni / Mo / X / Y / Ti multilayer metal system, which includes two parts, the upper Ni / Mo / X / Y / Ti multilayer metal system is wider than the lower Ni / Mo / X / Y / Ti multilayer metal system width; the upper and lower Ni / Mo / X / Y / Ti multilayer metal systems form a "T"-shaped gate electrode Ni / Mo / X / Y / Ti / Ni / Mo / X / Y / Ti; wherein the Ni metal layer and the Mo metal layer form a Schottky contact with the AlGaN barrier layer 33 below, the preferred thickness of the Ni metal layer is 5nm-10nm, and the preferred thickness of the Mo metal layer is 10nm-30nm; X metal The layer is Ti, the preferred thickness of the Ti metal layer is 70-150nm, and the Y metal layer is Au / Pt / Au or Al / Pt / Al or Cu / Pt / Cu, its main function is to reduce the gate resistance and improve the frequency characterist...

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Abstract

The invention discloses a Schottky contact system applicable to an AlGaN / GaN high electron mobility transistor (HEMT). The gate electrode of the AlGaN / GaN HEMT adopts the Schottky contact system with a two-layer Ni / Mo / Ti / Pt / Y / Ti structure, and the width of the second Ni / Mo / X / Y / Ti layer is larger than that of the first Ni / Mo / X / Y / Ti layer; the Schottky contact system adopts an evaporation method to sequentially deposit Ni, Mo, X, Y, Ti, Ni, Mo, X, Y, and Ti on the surface of an AlGaN barrier layer to form the gate electrode, the X metal layer is Ti or Ti / Pt or Ti / Pt / Ti / Pt or Ti / Mo / Ti / Mo, and the Y metal layer is Au or Al or Cu or Au / Pt / Au or Al / Pt / Al or Cu / Pt / Cu. Compared with the traditional Schottky contact system, the Schottky contact system in the invention has smaller thermal expansion coefficient and a lower thermal conductivity, the metal layer has a lower temperature than an epitaxial layer when the device works, influences on the device performance and the reliability by thermal expansion factors are avoided, gate resistance is also reduced, and the frequency features of the device are enhanced.

Description

technical field [0001] The invention relates to a Schottky contact system with a composite metal barrier layer suitable for AlGaN / GaN high electron mobility transistors. Background technique [0002] Aluminum Gallium Nitride (AlGaN) / Gallium Nitride (GaN) High Electron Mobility Transistor (HEMT) is a third-generation wide bandgap compound semiconductor device. What semiconductor technology does not have makes it a unique advantage in leading microwave applications, thus becoming a hot spot in the research of semiconductor microwave power devices. In recent years, researchers have made great breakthroughs in the microwave performance of AlGaN / GaN HEMTs, especially in terms of output power capability. The output power density of the currently disclosed small-size AlGaN / GaN HEMTs can reach more than 30W / mm in the X-band (Wu et al. IEEE Electron Device Lett., Vol.25, No.3, pp.117-119, 2004.), the Ka-band output power even reached 10W / mm or more (T. Palacios et al., IEEE ELECTRO...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L29/778H01L29/423
CPCH01L29/4232H01L29/42372H01L29/7781
Inventor 任春江陈堂胜
Owner NO 55 INST CHINA ELECTRONIC SCI & TECHNOLOGYGROUP CO LTD