CN111403479A - HEMT device with multi-metal gate structure and preparation method thereof - Google Patents

HEMT device with multi-metal gate structure and preparation method thereof Download PDF

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Publication number
CN111403479A
CN111403479A CN202010204549.8A CN202010204549A CN111403479A CN 111403479 A CN111403479 A CN 111403479A CN 202010204549 A CN202010204549 A CN 202010204549A CN 111403479 A CN111403479 A CN 111403479A
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metal
layer
gate electrode
electrode
gate structure
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CN202010204549.8A
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王洪
高升
刘晓艺
胡文龙
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South China University of Technology SCUT
Zhongshan Institute of Modern Industrial Technology of South China University of Technology
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South China University of Technology SCUT
Zhongshan Institute of Modern Industrial Technology of South China University of Technology
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Priority to CN202010204549.8A priority Critical patent/CN111403479A/en
Publication of CN111403479A publication Critical patent/CN111403479A/en
Priority to PCT/CN2020/132690 priority patent/WO2021189923A1/en
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00Semiconductor 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
    • H01L29/66Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/68Types 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
    • H01L29/76Unipolar devices, e.g. field effect transistors
    • H01L29/772Field effect transistors
    • H01L29/778Field effect transistors with two-dimensional charge carrier gas channel, e.g. HEMT ; with two-dimensional charge-carrier layer formed at a heterojunction interface
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00Semiconductor 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
    • H01L29/40Electrodes ; Multistep manufacturing processes therefor
    • H01L29/41Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions
    • H01L29/423Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions not carrying the current to be rectified, amplified or switched
    • H01L29/42312Gate electrodes for field effect devices
    • H01L29/42316Gate electrodes for field effect devices for field-effect transistors
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00Semiconductor 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
    • H01L29/40Electrodes ; Multistep manufacturing processes therefor
    • H01L29/43Electrodes ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
    • H01L29/47Schottky barrier electrodes
    • H01L29/475Schottky barrier electrodes on AIII-BV compounds
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00Semiconductor 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
    • H01L29/66Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/66007Multistep manufacturing processes
    • H01L29/66075Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
    • H01L29/66227Multistep 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
    • H01L29/66409Unipolar field-effect transistors
    • H01L29/66446Unipolar 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]
    • H01L29/66462Unipolar 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

Abstract

The invention discloses a HEMT device with a multi-metal gate structure and a preparation method thereof. The device comprises AlGaN/GaN epitaxy, wherein two ends of the upper surface of the AlGaN/GaN epitaxy are respectively connected with a source drain electrode, a gate electrode is arranged on the source drain electrode close to the source side, a first layer of metal X of the gate electrode is deposited in an electron beam evaporation mode, a second layer of metal Y of the gate electrode is deposited in a magnetron sputtering mode, the work function of the second layer of metal Y of the gate electrode is higher than that of the first layer of metal X, photoetching is not needed, and the metal structure which is formed after the gate electrode is stripped and is in contact with (Al) GaN is Y/X/Y. The (Al) GaN is contacted with a multi-metal gate structure, so that an electric field is redistributed, the electric field peak value close to the edge of a grid electrode of a drain electrode is reduced, and the breakdown voltage of a device is improved; meanwhile, the lower electric field peak value at the edge of the grid electrode weakens the injection of electrons into the grid electrode to form a virtual grid effect, reduces the current collapse of the device and improves the dynamic performance of the device.

Description

HEMT device with multi-metal gate structure and preparation method thereof
Technical Field
The invention relates to the field of semiconductors, in particular to a HEMT device with a multi-metal-gate structure and a preparation method thereof.
Background
The breakdown voltage of the GaN-based HEMT Device is far from reaching the theoretical limit value (3.4 MV/cm) of the GaN material, the Device is easy to break down between grid and drain, and how to reduce the high electric field peak value of the grid edge close to the drain side is beneficial to improving the breakdown voltage of the Device.
The current equipment for depositing metals is generally electron beam evaporation or magnetron sputtering. The magnetron sputtering equipment mainly bombards a target material by argon ions and sputters atoms of the material to the surface of a wafer; the electron beam evaporation equipment mainly melts the material by heating, and after reaching the boiling point, particles of the material are separated from the surface of the material one by one and reach the surface of the wafer. For magnetron sputtering equipment, the sputtering distance is short, mainly relates to collision among particles, a mean free path of particle motion is considered, similar to a point light source, the angle among the particles is large, and therefore, the area of material sputtered on the surface of a wafer is larger than that of a defined photoetching window; the electron beam evaporation chamber is long, and similar to a parallel light source, the metal material is vertically evaporated on the surface of the wafer.
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 control precisely and has poor reproducibility.
Disclosure of Invention
The invention provides an HEMT device with a multi-metal grid structure, wherein a second layer of metal Y prepared by magnetron sputtering completely wraps a first layer of metal X prepared by electron beams to form a YXY metal grid structure, so that the distribution of an electric field is adjusted, the electric field peak value of the edge of a grid close to a drain electrode is reduced, and the breakdown voltage of the device is improved; meanwhile, the influence of injection of electrons into the grid electrode to form a virtual grid on the current collapse of the device is weakened by the lower electric field peak value at the edge of the grid electrode, and the dynamic performance of the device is improved.
The object of the present invention is achieved by at least one of the following means.
The invention provides an HEMT device with a multi-metal-gate structure, which comprises AlGaN/GaN epitaxy, wherein two ends of the upper surface of the AlGaN/GaN epitaxy are respectively connected with a source drain electrode, the source drain electrode is provided with a gate electrode close to the source side, a first layer of metal X of the gate electrode is deposited in an electron beam evaporation mode, a second layer of metal Y of the gate electrode is deposited in a magnetron sputtering mode, the work function of the second layer of metal Y of the gate electrode is higher than that of the first layer of metal X, no extra photoetching step is needed, and the metal structure which is formed after the gate electrode is stripped and is in contact with (Al) GaN is Y/X/Y.
The invention adopts a method of combining electron beams and magnetron sputtering, realizes a multi-metal grid structure Y/X/Y after metal stripping, does not need to change the deposition angle of the electron beams, only needs the traditional deposition mode for the electron beams and the magnetron sputtering, has repeatability, and realizes a three-layer grid metal process based on the method of the invention compared with the double-layer grid metal process.
The invention provides a HEMT device with a multi-metal gate structure, which comprises: AlGaN/GaN epitaxy, source and drain electrodes and a gate electrode; two ends of the upper surface of the AlGaN/GaN epitaxy are respectively connected with a source drain electrode; the gate electrode is connected with the upper surface of the AlGaN/GaN epitaxy; the gate electrode comprises a first layer of metal X and a second layer of metal Y; and the metal structure which is formed after the gate electrode is stripped and is in contact with the (Al) GaN is Y/X/Y.
The HEMT device with the multi-metal-gate structure is an AlGaN/GaN HEMT device.
Further, the length of the second layer metal Y on both sides of the first layer metal X is 0.5-1 μm.
Further, the second layer of metal Y completely wraps the first layer of metal X.
Further, the distance from the gate electrode to the source is smaller than the distance from the gate electrode to the drain, that is, the gate electrode is disposed on the source side of the source-drain electrode.
The invention provides a method for preparing an HEMT device with a multi-metal gate structure, which comprises the following steps:
(1) defining a source and drain electrode window on the AlGaN/GaN epitaxy, preparing a source and drain electrode, and annealing to form ohmic contact;
(2) and defining a gate electrode photoetching window, and preparing a multi-metal gate structure Y/X/Y to obtain the HEMT device with the multi-metal gate structure.
Further, the photoetching window of the gate electrode in the step (2) is designed to be 1-2 μm.
Further, in the multi-metal-grid structure Y/X/Y in the step (2), a first layer of metal X is deposited in an electron beam evaporation mode, and a second layer of metal Y is deposited in a magnetron sputtering mode; and the thickness of the second layer of metal Y is greater than the thickness of the first layer of metal X.
Further, in the multi-metal gate structure Y/X/Y in the step (2), the first layer metal X is one of Ni, Ti, TiN and the like, and the second layer metal Y is one of Cu, W, Ni and the like.
Compared with the prior art, the invention has the following beneficial effects and advantages:
according to the invention, the electron beam and the multi-metal grid prepared by magnetron sputtering are utilized, no extra photoetching step is needed, the second layer of metal Y prepared by magnetron sputtering completely wraps the first layer of metal X prepared by the electron beam, and a multi-metal grid structure Y/X/Y is formed; the electric field distribution is adjusted, the electric field peak value close to the edge of the grid electrode of the drain electrode is reduced, and the breakdown voltage of the device is improved; meanwhile, the electric field peak value at the lower grid edge weakens the virtual grid effect formed by injecting electrons into the grid, and the saturation capacitance (158 pF) of the corresponding W/TiN/W structure device is reduced by 13.9 percent compared with the TiN structure device (136 pF) under the test frequency of 10KHz by testing the C-V characteristic, so that the dynamic performance of the device is improved.
Drawings
Fig. 1 is a schematic view of an epitaxial layer of a GaN-based HEMT device of an embodiment before a source-drain contact electrode is prepared;
FIG. 2 is a schematic view of a device structure after a source-drain contact electrode is manufactured and an ohmic contact is formed by annealing according to an embodiment;
FIG. 3 is a schematic diagram of a device structure after a gate electrode is formed according to an embodiment;
fig. 4 is a graph of capacitance data of a HEMT device having a multi-metal gate structure and a device of a TiN structure prepared in example 2;
in the figure, AlGaN/GaN epitaxy 1, source-drain electrode 2 and gate electrode 3.
Detailed Description
The following examples are presented to further illustrate the practice of the invention, but the practice and protection of the invention is not limited thereto. It is noted that the processes described below, if not specifically described in detail, are all realizable or understandable by those skilled in the art with reference to the prior art.
Example 1
The embodiment provides a HEMT device with a multi-metal gate structure, as shown in fig. 3, the device comprises an AlGaN/GaN extension 1, two ends of the upper surface of the AlGaN/GaN extension are respectively connected with a source drain electrode 2, a gate electrode 3 is arranged on the source drain electrode 2 close to the source side, a first layer of metal Ti of the gate electrode 3 is deposited in an electron beam evaporation mode, a second layer of metal Ni of the gate electrode 3 is deposited in a magnetron sputtering mode, no additional photoetching step is needed, and a metal structure which is formed after the gate electrode 3 is stripped and is in contact with (Al) GaN is Ni/Ti/Ni. In FIG. 3, G-1 represents a first layer metal, and G-2 represents a second layer metal.
The embodiment also provides a method for preparing the HEMT device with the multi-metal gate structure, which comprises the following steps:
(1) defining a source-drain electrode window on AlGaN/GaN epitaxy (an epitaxial layer before preparing a source-drain contact electrode is shown in figure 1) 1, preparing a source-drain electrode 2 and annealing to form ohmic contact, as shown in figure 2;
(2) defining a photoetching window of a gate electrode 3, and preparing a multi-metal gate structure Ni/Ti/Ni as shown in figure 3; the gate photoetching window of the HEMT device is designed to be 1 mu m, in a metal structure Ni/Ti/Ni formed after the gate electrode is stripped, the length of a second layer of metal Ni on two sides of a first layer of metal Ti is 0.7 mu m, the thickness of the first layer of metal Ti is 50nm, the thickness of the second layer of metal Ni is 250 nm, and the second layer of metal Ni completely wraps the first layer of metal Ti, so that the HEMT device with the multi-metal gate structure is obtained.
The HEMT device having the multi-metal gate structure prepared in example 1 has good dynamic performance and low saturation capacitance, as shown in fig. 4.
Example 2
The embodiment provides a HEMT device with a multi-metal gate structure, as shown in fig. 3, the device comprises an AlGaN/GaN extension 1, two ends of the upper surface of the AlGaN/GaN extension are respectively connected with a source drain electrode 2, a gate electrode 3 is arranged on the source drain electrode 2 close to the source side, a first layer of metal TiN of the gate electrode 3 is deposited in an electron beam evaporation mode, a second layer of metal W of the gate electrode 3 is deposited in a magnetron sputtering mode, no extra photoetching step is needed, and a metal structure which is formed after the gate electrode 3 is stripped and is in contact with (Al) GaN is W/TiN/W.
The embodiment also provides a method for preparing the HEMT device with the multi-metal gate structure, which comprises the following steps:
(1) defining a source and drain electrode window on the AlGaN/GaN epitaxy layer 1, preparing a source and drain electrode 2, and annealing to form ohmic contact, as shown in FIG. 2;
(2) defining a photoetching window of a gate electrode 3, and preparing a multi-metal gate structure W/TiN/W as shown in figure 3; the gate photoetching window of the HEMT device is designed to be 1 micrometer, in a metal structure W/TiN/W formed after the gate electrode is stripped, the length of a second layer of metal W on two sides of a first layer of metal TiN is 0.5 micrometer, the thickness of the first layer of metal TiN is 50nm, the thickness of the second layer of metal W is 200nm, and the second layer of metal W completely wraps the first layer of metal TiN, so that the HEMT device with the multi-metal gate structure is obtained.
Fig. 4 is a comparison graph of C-V characteristics of HEMT devices (W/TiN/W) having a multi-metal gate structure prepared in example 2, showing only the corresponding capacitance data at a test frequency of 10KHz, and it can be seen that the saturation capacitance values of the devices having the W/TiN/W structure are lower than those of the devices having the TiN structure.
The above examples are only preferred embodiments of the present invention, which are intended to be illustrative and not limiting, and those skilled in the art should understand that they can make various changes, substitutions and alterations without departing from the spirit and scope of the invention.

Claims (8)

1. A HEMT device having a multi-metal gate structure, comprising: AlGaN/GaN epitaxy, source and drain electrodes and a gate electrode; two ends of the upper surface of the AlGaN/GaN epitaxy are respectively connected with a source drain electrode; the gate electrode is connected with the upper surface of the AlGaN/GaN epitaxy; the gate electrode comprises a first layer of metal X and a second layer of metal Y; and the metal structure which is formed after the gate electrode is stripped and is in contact with the (Al) GaN is Y/X/Y.
2. The HEMT device with the multi-metal gate structure according to claim 1, wherein said second layer metal Y on both sides of said first layer metal X has a length of 0.5-1 μm.
3. The HEMT device with the multi-metal gate structure of claim 1, wherein said two-layer metal Y completely encapsulates said first layer metal X.
4. The HEMT device with the multi-metal gate structure according to claim 1, wherein a distance from said gate electrode to said source is smaller than a distance from said gate electrode to said drain.
5. A method of manufacturing a HEMT device having a multi-metal gate structure according to any one of claims 1 to 4, comprising the steps of:
(1) defining a source and drain electrode window on the AlGaN/GaN epitaxy, preparing a source and drain electrode, and annealing to form ohmic contact;
(2) and defining a gate electrode photoetching window, and preparing a multi-metal gate structure Y/X/Y to obtain the HEMT device with the multi-metal gate structure.
6. The method for manufacturing an HEMT device having a multi-metal gate structure according to claim 5, wherein a photolithography window of said gate electrode of step (2) is designed to be 1-2 μm.
7. The method for preparing an HEMT device with a multi-metal gate structure according to claim 5, wherein in the multi-metal gate structure Y/X/Y in the 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 thickness of the second layer of metal Y is greater than the thickness of the first layer of metal X.
8. The method according to claim 5, wherein in the multi-metal gate structure Y/X/Y in the step (2), the first layer metal X is one of Ni, Ti and TiN, and the second layer metal Y is one of Cu, W and Ni.
CN202010204549.8A 2020-03-21 2020-03-21 HEMT device with multi-metal gate structure and preparation method thereof Pending CN111403479A (en)

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PCT/CN2020/132690 WO2021189923A1 (en) 2020-03-21 2020-11-30 Hemt device having multi-metal gate structure and fabrication method therefor

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021189923A1 (en) * 2020-03-21 2021-09-30 中山市华南理工大学现代产业技术研究院 Hemt device having multi-metal gate structure and fabrication method therefor
CN113725287A (en) * 2021-07-21 2021-11-30 中山市华南理工大学现代产业技术研究院 Low-temperature gold-free ohmic contact GaN-based HEMT device and preparation method thereof

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US8318562B2 (en) * 2007-04-02 2012-11-27 University Of South Carolina Method to increase breakdown voltage of semiconductor devices
CN104377241B (en) * 2014-09-30 2017-05-03 苏州捷芯威半导体有限公司 Power semiconductor device and manufacturing method thereof
CN106158948B (en) * 2015-04-10 2020-05-19 中国科学院苏州纳米技术与纳米仿生研究所 III-nitride enhanced HEMT device and manufacturing method thereof
EP3326208A4 (en) * 2015-07-17 2019-03-06 Cambridge Electronics, Inc. Field-plate structures for semiconductor devices
CN111403479A (en) * 2020-03-21 2020-07-10 中山市华南理工大学现代产业技术研究院 HEMT device with multi-metal gate structure and preparation method thereof

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021189923A1 (en) * 2020-03-21 2021-09-30 中山市华南理工大学现代产业技术研究院 Hemt device having multi-metal gate structure and fabrication method therefor
CN113725287A (en) * 2021-07-21 2021-11-30 中山市华南理工大学现代产业技术研究院 Low-temperature gold-free ohmic contact GaN-based HEMT device and preparation method thereof
WO2023000692A1 (en) * 2021-07-21 2023-01-26 中山市华南理工大学现代产业技术研究院 Low-temperature gold-free ohmic contact gan-based hemt device and preparation method therefor

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