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VACUUM CHANNEL TRANSISTOR AND METHOD FOR MANUFACTURING SAME

Foreign code F170008921
File No. (S2015-1431-N0)
Posted date Jan 19, 2017
Country WIPO
International application number 2016JP064390
International publication number WO 2016182080
Date of international filing May 13, 2016
Date of international publication Nov 17, 2016
Priority data
  • P2015-099497 (May 14, 2015) JP
Title VACUUM CHANNEL TRANSISTOR AND METHOD FOR MANUFACTURING SAME
Abstract Provided is a vacuum channel transistor which uses a gallium nitride-aluminum nitride mixed crystal semiconductor, and wherein the electron emission efficiency is improved and the threshold voltage for electron emission is decreased. This vacuum channel transistor comprises: a conductor substrate 11 that constitutes a gate electrode; an insulating layer 12 that is formed on the conductor substrate and is formed of an insulating body; a source electrode 131 that is formed on the insulating layer; and a drain electrode 132 that is formed on the insulating layer so as to face the source electrode. The source electrode is formed of a crystal of a gallium nitride-aluminum nitride mixed crystal semiconductor having a wurtzite structure, and is arranged so that the angle between the main emission direction of electrons and the c-axis direction of the crystal structure is 30° or less.
Outline of related art and contending technology BACKGROUND ART
Current, an electromagnetic wave and there is a high-frequency use, the terahertz wave is close to the frequency region of the light, the imaging for the next generation high speed wireless communication and monitoring, gene, protein functional analysis of the many applications such as medical applications have been expected. It should be noted that, generally referred to as the terahertz wave is an electromagnetic wave frequency may be 100GHz - 10THz, here 1THz - 10THz and the electromagnetic wave of the terahertz wave.
The frequency range of 1THz - 10THz toward the practical use of the device, the low frequency side with respect to the electronic research and development and advancement, the high-frequency side with respect to research and development engineering such as photons (photonics) has been pushed. That is, electronic approach to speed up the electronic device 1THz its operating frequency is greater than the aim has been developed. On the other hand, in the semiconductor laser and a photonics approach the wavelength of light generated in the quantum cascade laser and a long wavelength equal to or less than 10THz attempts to reduce the occurrence frequency of the electromagnetic wave have been made.
However, the speed of the electronic device in the electronic engineering approach is limited, practical use is still greater than 1THz the electronic device is an electromagnetic wave can be generated cannot be realized. In addition, the low frequency of the optical device in the photonics approach is limited and, the electromagnetic wave can be generated practically 10THz or less cannot be realized the optical device. In addition, with respect to the optical device, the optical transition photon 1THz - 10THz corresponding to the energy level difference becomes closer to the thermal energy of room temperature, the thermal energy at room temperature for being disturbed by, the operation of the optical device at room temperature is a problem that it becomes more difficult.
In this way, many promising applications is in the terahertz wave region, in the electronic engineering approach, even in the photonics approach, the occurrence of electromagnetic waves in this region the device is practically performed is not realized yet. With respect to the region of the electromagnetic wave of frequency 1THz - 10THz, substantially the occurrence of electromagnetic waves cannot be performed and signal processing have been left behind as a blank region.
In the terahertz region as described above overcomes these problems as is aimed at, as shown in the following Non-Patent Document 1 a gate insulating type vacuum channel transistor have been proposed. Is in Non-Patent Document 1, electrons as a carrier traveling in the channel of a vacuum space of the field effect transistor structure is described. The normal of the channel is provided in the semiconductor field-effect transistor, the upper limit of the operating speed determined by the semiconductor material depends on the saturation velocity of electrons. However, the speed of the electrons traveling in a vacuum rather than the saturation speed, theoretically electrons to the vicinity of the light velocity can be accelerated.
For this reason the vacuum channel transistor in the terahertz region of the electromagnetic wave to be generated can be expected. However, the vacuum channel transistor in the non-patent document 1, remains as the actual cutoff frequency of 0.46THz, 1THz cannot exceed the wall. The reason for this efficiency to emit electrons from the source is considered to be small. Non-Patent Document 1 of the vacuum channel transistor, the source electrode tip has a sharp shape, further a small distance between the source and drain as the electron-emitting efficiency is accordingly improved when it is, nevertheless a sufficient efficiency cannot be obtained.
A voltage is applied between the source and drain current begins to flow to a minimum voltage and the threshold voltage is referred to, non-patent document 1 of the vacuum channel transistor threshold voltage of about 10V are required, the value of the threshold voltage is relatively large. This is, at the source of the electron emission efficiency is still not sufficient to indicate that. Non-Patent Document 1 is based on silicon and the first source device, the drain electrodes of silicon.
Is greater than the electron affinity of silicon, field emission electrons in the silicon electrode in a large electron affinity for electrons corresponding to the energy must be provided. Therefore, the threshold voltage is higher, the electron-emitting efficiency is lower, power consumption is increased. Further, electrode shape and an acutely angled shape by fine processing such as to generate a high electric field concentration is also needed.
On the other hand, a mixed crystal semiconductor of gallium nitride - aluminum nitride by using the electrode, to improve the electron-emitting efficiency have been proposed electronic devices. In a mixed crystal semiconductor of gallium nitride - aluminum nitride and aluminum nitride and the ratio of the x. Here, x is the ratio, the ratio of the number of molecules of aluminum nitride with respect to the whole and, at 0 ≦ x ≦ 1. It should be noted that, in the case of a mixed crystal semiconductor of x=0, 1 is actually a pure compound is, for the sake of convenience herein and in the case of a mixed crystal semiconductor including described.
That is, this mixed crystal semiconductor, Alx Ga1-x Ncan be represented. In the case of the ratio x is 0, this mixed crystal semiconductor is gallium nitride and, the electron affinity is on the order of 3.3eV, and a positive electron affinity. X is increased as the ratio of aluminum nitride has an electron affinity is reduced. Ratio x is about 0.65 and 0 is approximately the electron affinity of a mixed crystal semiconductor. X is 1 and the ratio of the aluminum nitride is the electron affinity becomes negative.
Such a mixed crystal semiconductor of gallium nitride - aluminum nitride used as an electronic device, such as the following Patent Document 1 is one. Patent Document 1 is, as the surface of the electrode layer using a mixed crystal semiconductor of gallium nitride - aluminum nitride, 0 or negative electron affinity as an electrode material and by using the material, the electron-emitting efficiency and to improve the electronic device are described.
Scope of claims (In Japanese)[請求項1]
窒化ガリウム-窒化アルミニウム混晶半導体のウルツ鉱型構造の結晶からなる電極(13)を有し、
前記電極(131)は、電子の主要な放出方向と結晶構造のc軸方向とのなす角度が30度以下となるように配置されたものである半導体素子。
[請求項2]
請求項1に記載した半導体素子であって、
前記電極(131)は、電子の主要な放出方向が結晶構造のc軸方向となるように配置されたものである半導体素子。
[請求項3]
請求項2に記載した半導体素子であって、
前記電極(131)は、窒化アルミニウムが分子数の比で全体の0.65以上となる窒化ガリウム-窒化アルミニウム混晶半導体からなるものである半導体素子。
[請求項4]
ゲート電極をなす導体基板(11)と、
前記導体基板(11)の上に形成された絶縁体からなる絶縁層(12)と、
前記絶縁層(12)の上に形成されたソース電極(131)と、
前記絶縁層(12)の上に形成され、前記ソース電極(131)と対向するように設けられたドレイン電極(132)とを有し、
前記ソース電極(131)は、窒化ガリウム-窒化アルミニウム混晶半導体のウルツ鉱型構造の結晶からなるものであり、電子の主要な放出方向と結晶構造のc軸方向とのなす角度が30度以下となるように配置されたものである真空チャネルトランジスタ。
[請求項5]
請求項4に記載した半導体素子であって、
前記ソース電極(131)は、電子の主要な放出方向が結晶構造のc軸方向となるように配置されたものである真空チャネルトランジスタ。
[請求項6]
請求項5に記載した真空チャネルトランジスタであって、
前記ソース電極(131)は、窒化アルミニウムが分子数の比で全体の0.65以上となる窒化ガリウム-窒化アルミニウム混晶半導体からなるものである真空チャネルトランジスタ。
[請求項7]
請求項6に記載した真空チャネルトランジスタであって、
前記導体基板(11)は、n型シリコンからなるものであり、
前記絶縁層(12)は、n型シリコン基板の表面に形成された二酸化ケイ素の層である真空チャネルトランジスタ。
[請求項8]
請求項7に記載した真空チャネルトランジスタであって、
前記ソース電極(131)は、当該ソース電極(131)に通電するための金属電極(21)が接続されたものである真空チャネルトランジスタ。
[請求項9]
請求項8に記載した真空チャネルトランジスタであって、
前記ソース電極(131)と前記金属電極(21)との間に、窒化ガリウム-窒化アルミニウム混晶半導体からなり、窒化アルミニウムの割合が前記金属電極(21)側から前記ソース電極(131)側に向かって増大する結合層(151)を有する真空チャネルトランジスタ。
[請求項10]
請求項9に記載した真空チャネルトランジスタであって、
前記金属電極(21)と前記結合層(151)との間に、窒化ガリウムからなる接触層(161)を有する真空チャネルトランジスタ。
[請求項11]
窒化ガリウムのウルツ鉱型構造の結晶からなり、表面がm面である基板(14)に、窒化ガリウム-窒化アルミニウム混晶半導体からなる半導体層(13)を結晶成長させる工程と、
n型シリコンからなる導体基板(11)の表面を酸化させて二酸化ケイ素からなる絶縁層(12)を形成する工程と、
前記絶縁層(12)の表面と前記半導体層(13)の表面を重ね合わせ、前記絶縁層(12)と前記半導体層(13)を結合する工程と、
前記基板(14)を前記半導体層(13)から剥離する工程と、
前記半導体層(13)をソース電極(131)とドレイン電極(132)として形成する工程とを有する真空チャネルトランジスタの製造方法。
[請求項12]
請求項11に記載した真空チャネルトランジスタの製造方法であって、
前記ソース電極(131)と前記ドレイン電極(132)とは、電子の主要な放出方向と前記半導体層(13)の結晶構造のc軸方向とのなす角度が30度以下となるように形成されるものである真空チャネルトランジスタの製造方法。
[請求項13]
請求項12に記載した真空チャネルトランジスタの製造方法であって、
前記ソース電極(131)と前記ドレイン電極(132)とは、電子の主要な放出方向が前記半導体層(13)の結晶構造のc軸方向となるように形成されるものである真空チャネルトランジスタの製造方法。
  • Applicant
  • ※All designated countries except for US in the data before July 2012
  • YAMAGUCHI UNIVERSITY
  • Inventor
  • YOKOGAWA, Toshiya
  • SANADA, Atsushi
IPC(International Patent Classification)
Specified countries National States: AE AG AL AM AO AT AU AZ BA BB BG BH BN BR BW BY BZ CA CH CL CN CO CR CU CZ DE DK DM DO DZ EC EE EG ES FI GB GD GE GH GM GT HN HR HU ID IL IN IR IS JP KE KG KN KP KR KZ LA LC LK LR LS LU LY MA MD ME MG MK MN MW MX MY MZ NA NG NI NO NZ OM PA PE PG PH PL PT QA RO RS RU RW SA SC SD SE SG SK SL SM ST SV SY TH TJ TM TN TR TT TZ UA UG US UZ VC VN ZA ZM ZW
ARIPO: BW GH GM KE LR LS MW MZ NA RW SD SL SZ TZ UG ZM ZW
EAPO: AM AZ BY KG KZ RU TJ TM
EPO: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
OAPI: BF BJ CF CG CI CM GA GN GQ GW KM ML MR NE SN ST TD TG

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