JPH0325030B2 - - Google Patents

Info

Publication number
JPH0325030B2
JPH0325030B2 JP61018208A JP1820886A JPH0325030B2 JP H0325030 B2 JPH0325030 B2 JP H0325030B2 JP 61018208 A JP61018208 A JP 61018208A JP 1820886 A JP1820886 A JP 1820886A JP H0325030 B2 JPH0325030 B2 JP H0325030B2
Authority
JP
Japan
Prior art keywords
gaas
gate electrode
layer
hexaboride
rare earth
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
JP61018208A
Other languages
Japanese (ja)
Other versions
JPS62177972A (en
Inventor
Hisao Nakajima
Tatsuo Yokozuka
Yoko Uchida
Tadashi Narisawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
National Institute of Advanced Industrial Science and Technology AIST
Original Assignee
Agency of Industrial Science and Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Agency of Industrial Science and Technology filed Critical Agency of Industrial Science and Technology
Priority to JP61018208A priority Critical patent/JPS62177972A/en
Publication of JPS62177972A publication Critical patent/JPS62177972A/en
Publication of JPH0325030B2 publication Critical patent/JPH0325030B2/ja
Granted legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
    • H10D30/00—Field-effect transistors [FET]
    • H10D30/60—Insulated-gate field-effect transistors [IGFET]
    • H10D30/67—Thin-film transistors [TFT]
    • H10D30/6729—Thin-film transistors [TFT] characterised by the electrodes
    • H10D30/6737—Thin-film transistors [TFT] characterised by the electrodes characterised by the electrode materials
    • H10D30/6738—Schottky barrier electrodes
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
    • H10D30/00—Field-effect transistors [FET]
    • H10D30/202—FETs having static field-induced regions, e.g. static-induction transistors [SIT] or permeable base transistors [PBT]
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
    • H10D30/00—Field-effect transistors [FET]
    • H10D30/60—Insulated-gate field-effect transistors [IGFET]
    • H10D30/67—Thin-film transistors [TFT]
    • H10D30/674—Thin-film transistors [TFT] characterised by the active materials
    • H10D30/675—Group III-V materials, Group II-VI materials, Group IV-VI materials, selenium or tellurium
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
    • H10D64/00—Electrodes of devices having potential barriers
    • H10D64/60—Electrodes characterised by their materials
    • H10D64/64—Electrodes comprising a Schottky barrier to a semiconductor
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
    • H10D62/00—Semiconductor bodies, or regions thereof, of devices having potential barriers
    • H10D62/80—Semiconductor bodies, or regions thereof, of devices having potential barriers characterised by the materials
    • H10D62/85—Semiconductor bodies, or regions thereof, of devices having potential barriers characterised by the materials being Group III-V materials, e.g. GaAs

Landscapes

  • Electrodes Of Semiconductors (AREA)
  • Bipolar Transistors (AREA)
  • Junction Field-Effect Transistors (AREA)

Description

【発明の詳細な説明】 （産業上の利用分野） この発明は、例えばGaAsを基板とし、希土類
元素の六硼化物をゲート電極として用いたパーミ
アブル・ベース・トランジスタ等の半導体装置に
関するものである。DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a semiconductor device such as a permeable base transistor using, for example, GaAs as a substrate and a rare earth element hexaboride as a gate electrode.

（従来の技術） 最近、GaAsを基板とするパーミアブル・ベー
ス・トランジスタが提案されている。その構造
は、例えば図面に示すこの発明のものと同一であ
るが、GaAs層２中に埋込まれるゲート電極３と
してタングステン等の材質が使用され、これによ
り電極４から電極５へと流れる電流を制御し、ト
ランジスタ動作を行なわせるものである。(Prior Art) Recently, permeable base transistors using GaAs as a substrate have been proposed. Its structure is, for example, the same as that of the present invention shown in the drawings, but a material such as tungsten is used as the gate electrode 3 embedded in the GaAs layer 2, and this allows current to flow from the electrode 4 to the electrode 5. It controls the transistor and causes it to operate.

このトランジスタは良好な高周波特性を得るこ
とを目的として提案されたもので、理論的には最
大発振周波数として約1000GHzが予測されてい
る。しかしながら、試作されたパーミアブル・ベ
ース・トランジスタでは最大発振周波数は17GHz
程度であつた。 This transistor was proposed with the aim of obtaining good high-frequency characteristics, and the maximum oscillation frequency is theoretically predicted to be approximately 1000 GHz. However, the maximum oscillation frequency of the prototype permable base transistor is 17GHz.
It was moderately hot.

（発明が解決しようとする問題点） 上述のパーミアブル・ベース・トランジスタに
おいて、理論的に予測される値ほど、試作された
トランジスタの高周波特性が良くないのは最適設
計がなされていないこともあるが、主してゲート
電極材料に問題がある。(Problem to be solved by the invention) Regarding the above-mentioned permeable base transistor, the reason why the high frequency characteristics of the prototype transistor are not as good as theoretically predicted values may be due to the fact that the design was not optimal. , the main problem lies in the gate electrode material.

即ち、GaAs層２内にゲート電極３を埋込むに
はエピタキシヤル成長が用いられているが、通常
エピタキシヤル成長は700〜800℃の高温で行なわ
れる。したがつて、GaAs層２とゲート電極３の
材料の熱膨張係数に差があると、歪が入り、エピ
タキシヤル成長層に欠陥が導入されるが、上述の
タングステンからなるゲート電極材料とGaAs層
についてはGaAsの熱膨張係数が5.7×10-6／℃に
対してゲート電極材料のタングステンの熱膨張係
数が4.5×10-6／℃と可成り差があり、このため
エピタキシヤル成長層の結晶性が悪くなり、電子
の移動度の低下を生じる。そして、この電子移動
度の低下は高周波特性に影響を与え、最大発振周
波数の低下を招くことになる。 That is, epitaxial growth is used to embed gate electrode 3 in GaAs layer 2, and epitaxial growth is usually performed at a high temperature of 700 to 800°C. Therefore, if there is a difference in thermal expansion coefficient between the materials of the GaAs layer 2 and the gate electrode 3, strain will occur and defects will be introduced into the epitaxially grown layer. Regarding GaAs, the coefficient of thermal expansion is 5.7×10 -6 /℃, while that of tungsten, the gate electrode material, is 4.5×10 -6 /℃, which is quite different. This results in a decrease in electron mobility. This decrease in electron mobility affects high frequency characteristics, leading to a decrease in the maximum oscillation frequency.

（問題点を解決するための手段） 上記問題点を解決するため、この発明では基板
両端に電極を有し、該基板中にはゲート電極が埋
込まれたパーミアブル・ベース・トランジスタ等
の半導体装置において、該ゲート電極の材質とし
て希土類元素の六硼化物を用いた半導体装置を提
案するものである。(Means for Solving the Problems) In order to solve the above problems, the present invention provides a semiconductor device such as a permeable base transistor that has electrodes at both ends of a substrate and a gate electrode embedded in the substrate. proposes a semiconductor device using a rare earth element hexaboride as the material for the gate electrode.

この発明でゲート電極材料として使用する希土
類元素の六硼化物としては特に4f希土類元素の六
硼化物が好ましく、例えばランタンの六硼化物
（LaB6）を使用することができる。また、セリウ
ム（Ce）、プラセオジム（Pr）、ネオジウム
（Nd）、ガドリウム（Gd）、テルビウム（Tb）、
イツテルビウム（Yb）の六硼化物のランタンの
六硼化物と同様にゲート電極として使用すること
ができる。 The hexaboride of a rare earth element used as the gate electrode material in this invention is particularly preferably a hexaboride of a 4f rare earth element, and for example, lanthanum hexaboride (LaB 6 ) can be used. In addition, cerium (Ce), praseodymium (Pr), neodymium (Nd), gadolinium (Gd), terbium (Tb),
Ytterbium (Yb) hexaboride can be used as a gate electrode similarly to lanthanum hexaboride.

また、上記ゲート電極を埋込む基板としては
GaAs基板等のGaAs系基板が好ましいが、Si系
の基板を使用することもできる。 In addition, as a substrate for embedding the above gate electrode,
Although a GaAs-based substrate such as a GaAs substrate is preferred, a Si-based substrate can also be used.

この発明に係る半導体装置の製法としては、通
常の方法に従つてエピタキシヤル成長により形成
したGaAs等の結晶層の上に、希土類元素の六硼
化物層を蒸着し、更に該希土類元素の六硼化物層
をＸ線リゾグラフイ法等により処理してゲート電
極を形成し、その後再びGaAs等の結晶層を成長
させて上記ゲート電極層をGaAs等の結晶層内に
埋込むとともに、GaAs等の結晶層の両端には電
極を形成するものである。 A method for manufacturing a semiconductor device according to the present invention includes depositing a hexaboride layer of a rare earth element on a crystal layer of GaAs or the like formed by epitaxial growth according to a conventional method, and then depositing a hexaboride layer of a rare earth element. The gate electrode is formed by processing the compound layer by X-ray lithography, etc., and then a crystal layer of GaAs etc. is grown again to embed the gate electrode layer in the crystal layer of GaAs etc. Electrodes are formed at both ends.

ここで、希土類元素の六硼化物層の蒸着は電子
銃によつて行なうのが簡便であり、この場合希土
類元素の六硼化物の単結晶もしくは粉末を焼結し
たペレツトに電子ビームを照射し、昇温された
GaAs等の結晶層上の所定の位置に希土類元素の
六硼化物層を蒸着する。 Here, it is convenient to deposit the hexaboride layer of the rare earth element using an electron gun. In this case, a pellet made by sintering a single crystal or powder of the hexaboride of the rare earth element is irradiated with an electron beam. the temperature was raised
A hexaboride layer of a rare earth element is deposited at a predetermined position on a crystal layer such as GaAs.

（作用） この発明で使用する希土類元素の六硼化物は、
希土類原子が硼素の作る正八面体によつて取り囲
まれた構造になつている。そして、硼素間の強い
共有結合のため、安定な化合物であり、融点は
2000℃以上と極めて高く、比抵抗は10-6〜
10-4Ω・cmと低く、特に4f希土類元素の六硼化物
の比抵抗、例えばランタンの六硼化物（LaB6）
の比抵抗は8.9×106Ω・cm-3と通常と変らない。
また、ランタンの六硼化物の熱膨張係数は5.6×
10-6／℃でGaAsの熱膨張係数5.7×10-6Ω・cmと
ほぼ一致している。(Function) The rare earth element hexaboride used in this invention is
It has a structure in which rare earth atoms are surrounded by regular octahedrons formed by boron. Because of the strong covalent bonds between boron, it is a stable compound with a melting point of
The temperature is extremely high at over 2000℃, and the specific resistance is 10 -6 ~
The resistivity is as low as 10 -4 Ω・cm, especially for 4f rare earth hexaborides, such as lanthanum hexaboride (LaB 6 ).
The specific resistance is 8.9×10 6 Ω・cm -3 , which is the same as normal.
Also, the coefficient of thermal expansion of lanthanum hexaboride is 5.6×
The coefficient of thermal expansion at 10 -6 /°C is almost the same as that of GaAs, which is 5.7×10 -6 Ω·cm.

したがつて、上述のように形成した希土類元素
の六硼化物蒸着層をGaAsエピタキシヤル成長膜
に埋込んでエピタキシヤル成長を行なつたが、熱
膨張の差による歪は観察されず、エピタキシヤル
成長層の欠陥の発生も観察されなかつた。 Therefore, epitaxial growth was performed by embedding the rare earth element hexaboride vapor deposited layer formed as described above in the GaAs epitaxial growth film, but no distortion due to the difference in thermal expansion was observed, and the epitaxial growth was No defects were observed in the grown layer.

また、GaAsエピタキシヤル成長層の結晶性は
良く、１×1016cm-3の電子濃度で、移動度7000
cm2／Vsecが得られ、高周波特性は大幅に改良さ
れる。 In addition, the crystallinity of the GaAs epitaxial growth layer is good, with an electron concentration of 1×10 16 cm -3 and a mobility of 7000.
cm 2 /Vsec is obtained, and the high frequency characteristics are greatly improved.

したがつて、この種のゲート電極はGaAs等の
基板内に埋込まれる電極として最適である。 Therefore, this type of gate electrode is most suitable as an electrode embedded in a substrate such as GaAs.

（実施例） 以下、この発明の実施例を示す。(Example) Examples of this invention will be shown below.

図面は、この発明の一実施例電極である示す
GaAsエピタキシヤル層中にLaB6を埋込んでゲー
ト電極とするパーミアブル・ベース・トランジス
タを示すもので、このパーミアブル・ベース・ト
ランジスタはn+形GaAs基板１（電子濃度：１×
1018cm-3）上に1μｍの厚さのGaAs層２（電子濃
度：４×1016cm-3）を分子線成長法でエピタキシ
ヤル成長させる。 The drawings show one embodiment of the electrode of this invention.
This shows a permable base transistor in which LaB 6 is buried in a GaAs epitaxial layer and used as a gate electrode.
10 18 cm -3 ), a 1 μm thick GaAs layer 2 (electron concentration: 4×10 16 cm -3 ) is epitaxially grown by molecular beam growth.

次に、GaAs層２に電子線蒸着法で厚さ300Å
のLaB6層を蒸着し、このLaB6膜を図示するよう
に公知のＸ線リゾブラフイ法でφ1600Å、間隔
1600Åの格子状ゲート電極３を形成し、その後再
び分子線成長法でGaAs層２をこの試料の上に1μ
ｍの厚さでエピタキシヤル成長させる。 Next, GaAs layer 2 is deposited to a thickness of 300 Å by electron beam evaporation.
6 layers of LaB were deposited, and this LaB 6 film was deposited with a diameter of 1600 Å and a spacing of
A lattice gate electrode 3 with a thickness of 1600 Å is formed, and then a GaAs layer 2 of 1 μm is deposited on this sample using the molecular beam growth method again.
Epitaxial growth is performed to a thickness of m.

その後、GaAs層２とGaAs基板１の両面に
AuGeNi合金膜を真空蒸着して電極４と５を形成
する。 After that, on both sides of GaAs layer 2 and GaAs substrate 1,
Electrodes 4 and 5 are formed by vacuum depositing an AuGeNi alloy film.

このようにして製造されたパーミアブル・ベー
ス・トランジスタは、GaAs層２のGaAsとゲー
ト電極材料であるLaB6の熱膨張係数が殆ど等し
いため、GaAs層２の結晶層中に歪が入らず、結
晶性の良い、移動度の高い成長層が得られる。そ
の結果、製作したパーミアブル・ベース・トラン
ジスタの最大発振周波数は30GHzであり、従来の
17GHzに比べて周波数特性の大幅な改善が見られ
た。 In the permeable base transistor manufactured in this way, the thermal expansion coefficients of GaAs of GaAs layer 2 and LaB6 , which is the gate electrode material, are almost equal, so no strain is introduced into the crystal layer of GaAs layer 2, and the crystalline A growth layer with good properties and high mobility can be obtained. As a result, the maximum oscillation frequency of the fabricated permable base transistor was 30 GHz, compared to conventional
Significant improvement in frequency characteristics was seen compared to 17GHz.

なお、この値は理論的に予測される最高の周波
数より低いが、これはゲート電極の厚さ、間隔が
最適でないためで、ここで作成したゲート電極、
間隔の長さを基準とすれば理論と良く一致してい
る。 Note that this value is lower than the highest frequency predicted theoretically, but this is because the thickness and spacing of the gate electrodes are not optimal.
If the length of the interval is used as a standard, it is in good agreement with theory.

（発明の効果） 以上要するに、この発明によればパーミアブ
ル・ベース・トランジスタ等基板中にゲート電極
が埋込まれた半導体装置の周波数特性を大幅に改
良することができる。(Effects of the Invention) In summary, according to the present invention, the frequency characteristics of a semiconductor device such as a permeable base transistor in which a gate electrode is embedded in a substrate can be significantly improved.

【図面の簡単な説明】[Brief explanation of the drawing]

図面は、この発明に係るパーミアブル・ベー
ス・トランジスタの一例を示す縦断側面図。 図中、１はGaAs基板、２はGaAs結晶層、３
はゲート電極、４，５は電極。 The drawing is a longitudinal side view showing an example of a permeable base transistor according to the present invention. In the figure, 1 is a GaAs substrate, 2 is a GaAs crystal layer, and 3
is a gate electrode, and 4 and 5 are electrodes.

Claims (1)

【特許請求の範囲】 １ 基板両端に電極を有し、該基板中にはゲート
電極が埋込まれた半導体装置において、該ゲート
電極の材質として希土類元素の六硼化物を用いた
ことを特徴とする半導体装置。 ２ 半導体装置がパーミアブル・ベース・トラン
ジスタである特許請求の範囲第１項記載の半導体
装置。[Claims] 1. A semiconductor device having electrodes at both ends of a substrate and a gate electrode embedded in the substrate, characterized in that a hexaboride of a rare earth element is used as a material for the gate electrode. semiconductor devices. 2. The semiconductor device according to claim 1, wherein the semiconductor device is a permeable base transistor.
JP61018208A 1986-01-31 1986-01-31 Semiconductor device Granted JPS62177972A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP61018208A JPS62177972A (en) 1986-01-31 1986-01-31 Semiconductor device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP61018208A JPS62177972A (en) 1986-01-31 1986-01-31 Semiconductor device

Publications (2)

Publication Number Publication Date
JPS62177972A JPS62177972A (en) 1987-08-04
JPH0325030B2 true JPH0325030B2 (en) 1991-04-04

Family

ID=11965228

Family Applications (1)

Application Number Title Priority Date Filing Date
JP61018208A Granted JPS62177972A (en) 1986-01-31 1986-01-31 Semiconductor device

Country Status (1)

Country Link
JP (1) JPS62177972A (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006186336A (en) * 2004-11-30 2006-07-13 Matsushita Electric Ind Co Ltd Field effect transistor and manufacturing method thereof

Also Published As

Publication number Publication date
JPS62177972A (en) 1987-08-04

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