JP6840327B2 - Diamond emission rectifying element and its manufacturing method - Google Patents
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Description
本発明は、ボロンやリンなどのドーパントを用いずに作製するダイヤモンド発光整流素子およびその製造方法に関する。 The present invention relates to a diamond emission rectifying device manufactured without using a dopant such as boron or phosphorus, and a method for manufacturing the same.
波長が３５０ｎｍ以下の深紫外領域の光は、高密度光記録や微細加工、殺菌、環境汚染物質の分解など多くの応用が考えられる。ダイヤモンドは室温で５．４７ｅＶの広いバンドギャップを持ち、深紫外発光が期待できる。このバンドギャップは間接遷移であるが、大きな束縛エネルギーを持つ自由励起子による再結合発光を使えば、高強度発光も期待できる。 Light in the deep ultraviolet region with a wavelength of 350 nm or less can be applied to many applications such as high-density light recording, microfabrication, sterilization, and decomposition of environmental pollutants. Diamond has a wide bandgap of 5.47 eV at room temperature and can be expected to emit deep ultraviolet light. This bandgap is an indirect transition, but high-intensity emission can also be expected by using recombination emission by free excitons with large binding energy.
そこで、特許文献１には、水素終端ダイヤモンド膜を用いたダイヤモンド紫外線発光素子が開示されている。しかし、当該発光素子は、電流注入によって発光する自由励起子再結合発光（波長２３５ｎｍ）が当該ダイヤモンド膜上の電極端部から放射されており、当該ダイヤモンド単結晶膜の表面に対して法線方向に放射するものではないため、例えば発光パネルの様な用途に適する発光形態でないという課題があった。（また、整流作用もほとんど見られなかった。） Therefore, Patent Document 1 discloses a diamond ultraviolet light emitting device using a hydrogen-terminated diamond film. However, in the light emitting element, free exciter recombination light emission (wavelength 235 nm) emitted by current injection is radiated from the electrode end portion on the diamond film, and is in the normal direction with respect to the surface of the diamond single crystal film. Since it does not radiate to light, there is a problem that it is not a light emitting form suitable for applications such as a light emitting panel. (Also, almost no rectifying effect was seen.)
また、ボロンドープ（ｐ型）およびリンあるいは硫黄ドープ（ｎ型）のダイヤモンドを使ったｐｎ接合およびｐｉｎ接合が開発され、波長２３５ｎｍ（５．２７ｅＶ）の励起子発光が観測されている。（例えば、特許文献２、３、４） In addition, pn junctions and pin junctions using boron-doped (p-type) and phosphorus- or sulfur-doped (n-type) diamonds have been developed, and exciton emission at a wavelength of 235 nm (5.27 eV) has been observed. (For example, Patent Documents 2, 3, 4)
しかし、リンや硫黄のドーピングによるｎ型ダイヤモンドの合成には、猛毒のホスフィンや硫化水素を使う必要がある。そこで、このようなｐｎ接合およびｐｉｎ接合のｎ型ダイヤモンドの合成には、密閉性の高い製造設備および除害（ガス浄化）設備が必要になるという課題があった。
またボロンおよびリンドープによる縦型ｐｎ接合の構造の場合、発光部が電極によって隠される。また、ダイヤモンドは高い屈折率をもち全反射の臨界角が小さい。（波長２３５ｎｍの場合２２°）そのため発光部から表面に対してこれ以上の角度をもって出射しようとする光は、ダイヤモンド表面で全反射され外に出ない。これらの理由により、光の外部への取り出し効率が低いという課題があった。
本発明は、上記の課題を解決するもので、ボロンやリンなどのドーピング層を有することなく、深紫外発光が可能なダイヤモンド発光整流素子およびその製造方法を提供することを目的とする。
However, it is necessary to use highly toxic phosphine and hydrogen sulfide for the synthesis of n-type diamond by doping with phosphorus and sulfur. Therefore, there is a problem that a highly airtight manufacturing facility and abatement (gas purification) facility are required for synthesizing such a pn junction and a pin junction n-type diamond.
Further, in the case of a vertical pn junction structure with boron and phosphorus dope, the light emitting portion is hidden by the electrode. In addition, diamond has a high refractive index and a small critical angle of total reflection. (22 ° in the case of a wavelength of 235 nm) Therefore, the light that is intended to be emitted from the light emitting portion at a larger angle with respect to the surface is totally reflected by the diamond surface and does not go out. For these reasons, there is a problem that the efficiency of extracting light to the outside is low.
An object of the present invention is to solve the above-mentioned problems, and to provide a diamond emission rectifying device capable of deep ultraviolet emission without having a doping layer such as boron or phosphorus, and a method for producing the same.
本発明者らは、ダイヤモンド表面の終端の違いによるエネルギーバンドのシフトに着目して、本願発明をするに至った。
そもそも、ダイヤモンドは各炭素原子が周りの４つの原子と共有結合で結び付いた結晶からなる。ダイヤモンドの表面では、結合手が余る。この未結合手は不安定で、水素や酸素などの元素と結合し安定化する。講学上は、この未結合手を安定化した状態を終端と言う。例えば、化学気相合成したダイヤモンドの表面は、合成中に水素プラズマに晒されるため水素終端となる。一方、酸素プラズマ照射などによって、酸素終端を作ることもできる。これらの水素および酸素終端は、大気中でも安定に保持される。
The present inventors have focused on the shift of the energy band due to the difference in the end of the diamond surface, and have arrived at the present invention.
In the first place, diamond consists of crystals in which each carbon atom is covalently bonded to the surrounding four atoms. On the surface of the diamond, there are extra bonds. This unbonded hand is unstable and stabilizes by binding to elements such as hydrogen and oxygen. In the course, the state in which this unbonded hand is stabilized is called the end. For example, the surface of chemically vapor-deposited diamond is hydrogen-terminated because it is exposed to hydrogen plasma during synthesis. On the other hand, oxygen termination can also be made by oxygen plasma irradiation or the like. These hydrogen and oxygen terminations are kept stable in the atmosphere.
ここで、水素終端ダイヤモンドは、負の電子親和力を持ち、また、大気に数時間晒すと表面にｐ型の伝導層が生じるという性質をもつ。これらの特性は、水素と炭素の電気陰性度の違いによって、水素側が正、炭素側が負の電気双極子が生じ、ダイヤモンドのエネルギーバンドが全体的に持ち上げられることによる。すなわち、伝導帯の底が真空準位より上に持ち上げられ、負の電子親和力（−１．３ｅＶ）となり、また、表面に吸着した水の層の中のＨ３Ｏ＋イオンの酸化還元準位に価電子帯の上部から電子が移動してホールが蓄積すると考えられている［非特許文献１参照］。 Here, hydrogen-terminated diamond has a negative electron affinity and has a property that a p-type conductive layer is formed on the surface when exposed to the atmosphere for several hours. These properties are due to the difference in electronegativity between hydrogen and carbon, which produces electric dipoles positive on the hydrogen side and negative on the carbon side, which lifts the diamond energy band as a whole. That is, the bottom of the conduction band is raised above the vacuum level, a negative electron affinity (-1.3eV), and the addition, the redox level of the H 3 O + ions in the layer of water adsorbed on the surface It is considered that electrons move from the upper part of the valence band and holes are accumulated [see Non-Patent Document 1].
一方、酸素終端表面では、水素終端の場合と逆向きの電気双極子が生じ、エネルギーバンドが下にシフトする。そのため正の電子親和力（＋１．７ｅＶ）となり。このような酸素終端表面ではｐ型表面伝導は現れず、ｎ型キャリア蓄積に有利となる［非特許文献２参照］。
このように、表面に生じる電気双極子によって、水素終端ではエネルギーバンドが上にシフトし、酸素終端では下にシフトする。
On the oxygen-terminated surface, on the other hand, an electric dipole is generated in the opposite direction to that of the hydrogen-terminated surface, and the energy band shifts downward. Therefore, it has a positive electron affinity (+ 1.7 eV). P-type surface conduction does not appear on such an oxygen-terminated surface, which is advantageous for n-type carrier accumulation [see Non-Patent Document 2].
Thus, the electric dipole generated on the surface shifts the energy band upwards at the hydrogen termination and downwards at the oxygen termination.
即ち、本発明は、上記の課題を解決するために、以下の構成としたダイヤモンド発光素子である。
本発明の第一のダイヤモンド発光素子は、例えば図１に示すように、ノンドープのダイヤモンドの表面を水素で終端した領域１、当該水素終端した領域１に隣接すると共に、前記ダイヤモンドの表面を酸素で終端した領域２、当該水素終端した領域１に設けられた水素終端側電極３、当該酸素終端した領域２に設けられた酸素終端側電極４とを備え、水素終端側電極３と酸素終端側電極４との間を流れる電流に対して、整流特性を示すことを特徴とする。
本発明では、このような水素終端の領域と酸素終端の領域をノンドープのダイヤモンド表面に隣接して形成することによって、ｐｎ接合と同様の内蔵電位差を生じさせ、発光整流素子を実現する（図４参照）。
That is, the present invention is a diamond light emitting device having the following configuration in order to solve the above problems.
In the first diamond light emitting element of the present invention, for example, as shown in FIG. 1, the surface of the non-doped diamond is adjacent to the hydrogen-terminated region 1 and the hydrogen-terminated region 1, and the surface of the diamond is oxygenated. A hydrogen-terminated region 2, a hydrogen-terminated electrode 3 provided in the hydrogen-terminated region 1, an oxygen-terminated electrode 4 provided in the oxygen-terminated region 2, and a hydrogen-terminated electrode 3 and an oxygen-terminated electrode are provided. It is characterized by exhibiting rectification characteristics with respect to the current flowing between the four.
In the present invention, by forming such a hydrogen-terminated region and an oxygen-terminated region adjacent to the non-doped diamond surface, a built-in potential difference similar to that of a pn junction is generated, and an emission rectifying element is realized (FIG. 4). reference).
本発明の第一のダイヤモンド発光素子において、好ましくは、前記水素終端側電極は、加熱処理により前記ダイヤモンドとの境界に炭化金属層を形成する金属、並びに、Ａｕ、Ｐｄ又はＰｔの少なくとも一種類を含むとよい。
本発明の第一のダイヤモンド発光素子において、好ましくは、前記酸素終端側電極は、Ｃａ並びに、Ｍｇ、Ｂａ、Ｙ、Ａｌ等の炭素と比較して仕事関数の低い金属の少なくとも一種類を含むとよい。
In the first diamond light emitting element of the present invention, preferably, the hydrogen termination side electrode is a metal that forms a carbide layer at the boundary with the diamond by heat treatment, and at least one of Au, Pd, and Pt. It should be included.
In the first diamond light emitting element of the present invention, preferably, the oxygen termination side electrode contains Ca and at least one kind of metal having a low work function as compared with carbon such as Mg, Ba, Y, and Al. Good.
本発明の第二のダイヤモンド発光素子は、ノンドープのダイヤモンドの表面を水素で終端した領域１、前記ダイヤモンドの表面であって、当該水素終端した領域に隣接したフッ素で終端した領域２、当該水素終端した領域１に設けられた水素終端側電極３、当該フッ素終端した領域２に設けられたフッ素終端側電極４とを備え、水素終端側電極３とフッ素終端側電極４との間を流れる電流に対して、整流特性を示すことを特徴とする。
The second diamond light emitting element of the present invention has a region 1 in which the surface of a non-doped diamond is terminated with hydrogen, a region 2 which is the surface of the diamond and is terminated by fluorine adjacent to the hydrogen-terminated region, and the hydrogen termination. A hydrogen-terminated electrode 3 provided in the region 1 and a fluorine-terminated electrode 4 provided in the fluorine-terminated region 2 are provided, and a current flowing between the hydrogen-terminated electrode 3 and the fluorine-terminated electrode 4 is applied. On the other hand, it is characterized by exhibiting rectification characteristics.
本発明の第一のダイヤモンド発光素子の製造方法は、例えば図２に示すように、酸素終端した領域を表面に有する、ノンドープのダイヤモンドを準備する工程と（Ｓ１００）、この酸素終端領域のうち水素終端側電極となる領域に加熱処理により前記ダイヤモンドとの境界に炭化金属層を形成する金属を含む金属層を積層する工程と（Ｓ１０２）、この金属層を加熱処理して、当該金属層と前記ダイヤモンドとの境界に炭化金属層を形成する工程と（Ｓ１０４）、この酸素終端領域を水素終端した領域に変換処理する工程と（Ｓ１０６）、この水素終端した領域のうち、水素終端した領域として保持すべき領域をマスクする工程と（Ｓ１０８）、このマスク処理されておらず、露出した水素終端した領域を酸素終端した領域に変換処理する工程と（Ｓ１１０）、前記マスク処理された水素終端した領域のマスク剤を除去する工程と（Ｓ１１２）、この酸素終端領域のうち酸素終端側電極となる領域に炭素と比較して仕事関数の低い金属を含む電極金属層を積層する工程と（Ｓ１１４）を有することを特徴とする。
本発明の第一のダイヤモンド発光素子において、好ましくは、前記仕事関数の低い金属は、Ｃａ、Ｍｇ、Ｂａ、Ｙ、Ａｌの少なくとも一種類を含むとよい。
The first method for producing a diamond light emitting element of the present invention includes, for example, as shown in FIG. 2, a step of preparing a non-doped diamond having an oxygen-terminated region on the surface (S100), and hydrogen in the oxygen-terminated region. A step of laminating a metal layer containing a metal that forms a metal carbide layer at the boundary with the diamond by heat treatment in a region to be a terminal electrode (S102), and a heat treatment of the metal layer to obtain the metal layer and the metal layer. A step of forming a metal carbide layer at the boundary with the diamond (S104), a step of converting the oxygen-terminated region into a hydrogen-terminated region (S106), and holding the hydrogen-terminated region as a hydrogen-terminated region. A step of masking the region to be processed (S108), a step of converting the unmasked and exposed hydrogen-terminated region into an oxygen-terminated region (S110), and the masked hydrogen-terminated region. A step of removing the masking agent (S112) and a step of laminating an electrode metal layer containing a metal having a lower work function than carbon in the region of the oxygen termination region to be the oxygen termination side electrode (S114). It is characterized by having.
In the first diamond light emitting device of the present invention, preferably, the metal having a low work function may contain at least one of Ca, Mg, Ba, Y, and Al.
本発明の第二のダイヤモンド発光素子の製造方法は、例えば図３に示すように、水素終端した領域を表面に有する、ノンドープのダイヤモンドを準備する工程と（Ｓ２００）、この水素終端領域のうち水素終端側電極となる領域にＡｕ、Ｐｄ、Ｐｔの少なくとも一種類を含む金属層を積層する工程と（Ｓ２０２）、この水素終端した領域のうち、水素終端した領域として保持すべき領域をマスクする工程と（Ｓ２０４）、このマスク処理されておらず、露出した水素終端した領域を酸素終端した領域に変換処理する工程と（Ｓ２０６）、前記マスク処理された水素終端した領域のマスク剤を除去する工程と（Ｓ２０８）、この酸素終端領域のうち酸素終端側電極となる領域に炭素と比較して仕事関数の低い金属を含む電極金属層を積層する工程と（Ｓ２１０）を有することを特徴とする。
本発明の第二のダイヤモンド発光素子において、好ましくは、前記仕事関数の低い金属は、Ｃａ、Ｍｇ、Ｂａ、Ｙ、Ａｌの少なくとも一種類を含むとよい。
The second method for producing a diamond light emitting element of the present invention includes, for example, as shown in FIG. 3, a step of preparing a non-doped diamond having a hydrogen-terminated region on the surface (S200), and hydrogen in the hydrogen-terminated region. A step of laminating a metal layer containing at least one of Au, Pd, and Pt on a region to be a terminal electrode (S202), and a step of masking a region to be retained as a hydrogen-terminated region among the hydrogen-terminated regions. (S204), a step of converting the exposed hydrogen-terminated region that has not been masked into an oxygen-terminated region (S206), and a step of removing the masking agent of the masked hydrogen-terminated region. And (S208), it is characterized by having a step (S210) of laminating an electrode metal layer containing a metal having a lower work function than carbon in a region of the oxygen termination region to be an oxygen termination side electrode.
In the second diamond light emitting device of the present invention, preferably, the metal having a low work function may contain at least one of Ca, Mg, Ba, Y, and Al.
本発明の第一又は第二のダイヤモンド発光素子の製造方法において、好ましくは、さらに、電極金属層を積層する工程の後に、封止用のＡｌ２Ｏ３膜の成膜処理をする工程（Ｓ１１６、Ｓ２１２）を含むとよい。
In the method for producing the first or second diamond light emitting element of the present invention, preferably, after the step of laminating the electrode metal layer, a step of forming a film of an Al 2 O 3 film for sealing (S116). , S212) may be included.
本発明のダイヤモンド発光素子によれば、不純物濃度の低い純粋なダイヤモンドを用いることができるため、結晶欠陥（窒素などの不純物を含む）由来の可視域の発光を抑えることが可能であり、深紫外発光の効率を上げることができるという効果がある。さらに、本発明のダイヤモンド発光素子によれば、発光部は水素終端−酸素終端の境界であり表面（表面から数ｎｍまでの深さ）に存在する。そのため電極に隠されることなく、効率的に光を取り出せるという効果がある。
また、本発明のダイヤモンド発光素子の製造方法によれば、ボロンやリンなどのドーパントを用いずに、ノンドープの（不純物濃度が非常に小さい）ダイヤモンドのみを使って発光整流素子を作製できるため、猛毒ガスであるホスフィンや硫化水素などを使ったドーピングを行う必要がなく、これらのガスの除害設備を有さない簡便な製造設備でダイヤモンド発光素子を製造できる。
According to the diamond luminous element of the present invention, since pure diamond having a low impurity concentration can be used, it is possible to suppress light emission in the visible region derived from crystal defects (including impurities such as nitrogen), and deep ultraviolet light. It has the effect of increasing the efficiency of light emission. Further, according to the diamond light emitting device of the present invention, the light emitting portion is a boundary between hydrogen termination and oxygen termination and exists on the surface (depth from the surface to several nm). Therefore, there is an effect that light can be efficiently taken out without being hidden by the electrodes.
Further, according to the method for producing a diamond light emitting device of the present invention, a light emitting rectifying device can be manufactured using only non-doped (very small impurity concentration) diamond without using dopants such as boron and phosphorus. It is not necessary to perform doping using phosphine, hydrogen sulfide, or the like, which are poisonous gases, and the diamond light emitting device can be manufactured by a simple manufacturing facility that does not have a facility for eliminating these gases.
以下、図面を用いて本発明を説明する。
図1は、本発明の一実施の形態によるダイヤモンド発光素子の構造模式図である。図において、ダイヤモンド発光素子は、水素終端領域１、酸素終端領域２、水素終端側電極３、酸素終端側電極４ならびに単結晶ダイヤモンド５を有している。
単結晶ダイヤモンド５は、例えば工業的に製造された人工ダイヤモンドを用いるものである。イリジウム等の金属やＳｉＣ等の上にヘテロエピタキシャル成長したダイヤモンドでも良い。なお、単結晶ダイヤモンド５に代えて、多結晶ダイヤモンドを用いても良い。多結晶ダイヤモンドの場合には、例えば化学蒸着（ＣＶＤ：chemical vapor deposition）を用いてシリコン等の基体の表面に膜状に生成されるとよい。
Hereinafter, the present invention will be described with reference to the drawings.
FIG. 1 is a schematic structural diagram of a diamond light emitting device according to an embodiment of the present invention. In the figure, the diamond light emitting device has a hydrogen termination region 1, an oxygen termination region 2, a hydrogen termination side electrode 3, an oxygen termination side electrode 4, and a single crystal diamond 5.
The single crystal diamond 5 uses, for example, an industrially manufactured artificial diamond. Diamond that is heteroepitaxially grown on a metal such as iridium or SiC or the like may be used. In addition, instead of the single crystal diamond 5, a polycrystalline diamond may be used. In the case of polycrystalline diamond, for example, chemical vapor deposition (CVD) may be used to form a film on the surface of a substrate such as silicon.
水素終端領域１は、単結晶ダイヤモンド５の表面を水素で終端した領域である。酸素終端領域２は、水素終端領域１に隣接した、単結晶ダイヤモンド５の表面を酸素で終端した領域である。水素終端側電極３は、水素終端領域１に設けられたものである。酸素終端側電極４は、酸素終端領域２に設けられたものである。そして、水素終端側電極３と酸素終端側電極４との間を流れる電流に対して、整流特性を示す。 The hydrogen termination region 1 is a region in which the surface of the single crystal diamond 5 is terminated with hydrogen. The oxygen-terminated region 2 is a region adjacent to the hydrogen-terminated region 1 in which the surface of the single crystal diamond 5 is terminated with oxygen. The hydrogen termination side electrode 3 is provided in the hydrogen termination region 1. The oxygen termination side electrode 4 is provided in the oxygen termination region 2. Then, the rectifying characteristic is shown with respect to the current flowing between the hydrogen terminal side electrode 3 and the oxygen terminal side electrode 4.
図２は、本発明の一実施の形態によるダイヤモンド発光素子の製造工程のフローチャートである。
最初に、単結晶ダイヤモンド５の表面の研磨および清浄化を行う。続いて、単結晶ダイヤモンド５の表面を水素プラズマに晒したのちにＵＶオゾン処理して、全面を酸素終端とする（Ｓ１００）。なお、酸素中加熱などによる酸素終端処理済みダイヤモンドを用いても良い。
FIG. 2 is a flowchart of a manufacturing process of a diamond light emitting device according to an embodiment of the present invention.
First, the surface of the single crystal diamond 5 is polished and cleaned. Subsequently, the surface of the single crystal diamond 5 is exposed to hydrogen plasma and then subjected to UV ozone treatment to terminate the entire surface with oxygen (S100). In addition, diamond which has been oxygen-terminated by heating in oxygen or the like may be used.
続いて、この酸素終端領域のうち水素終端側電極となる領域に、Tiを含む金属層を積層する（Ｓ１０２）。次に、この金属層をアルゴンあるいは水素雰囲気下で熱処理して、当該金属層とダイヤモンドとの境界に炭化金属（TiC）層を形成する（Ｓ１０４）。Ｔｉを用いる場合には、炭化金属層はＴｉＣとなる。また、加熱処理の温度は、例えば４００℃から６００℃、好ましくは４２０℃から４８０℃、特に好ましくは４４０℃から４６０℃の範囲とする。加熱処理の時間は、当該金属層とダイヤモンドとの境界に炭化金属層を形成してオーミック電極を形成するのに充分な時間であればよく、例えば１０分から１時間とし、好ましくは２０分から４０分の範囲とする。連続プロセスであれば、加熱処理の時間が短い場合には処理効率が上がるため、一般的には加熱処理の時間の時間は短い方が良い。 Subsequently, a metal layer containing Ti is laminated on the region of the oxygen termination region that serves as the hydrogen termination side electrode (S102). Next, this metal layer is heat-treated in an argon or hydrogen atmosphere to form a metal carbide (TiC) layer at the boundary between the metal layer and diamond (S104). When Ti is used, the carbide layer is TiC. The temperature of the heat treatment is, for example, 400 ° C. to 600 ° C., preferably 420 ° C. to 480 ° C., and particularly preferably 440 ° C. to 460 ° C. The heat treatment time may be sufficient as long as it is sufficient to form a metal carbide layer at the boundary between the metal layer and diamond to form an ohmic electrode, for example, 10 minutes to 1 hour, preferably 20 minutes to 40 minutes. The range of. In the case of a continuous process, if the heat treatment time is short, the treatment efficiency is increased. Therefore, it is generally preferable that the heat treatment time is short.
次に、この酸素終端領域を水素終端した領域に変換処理する（Ｓ１０６）。この変換処理には、例えば水素プラズマに５分ないし１０分程度晒すとよい。次に、この水素終端した領域のうち、水素終端した領域として保持すべき領域をマスクする（Ｓ１０８）。このマスク剤としては、例えばＡｌを用いるが、酸素終端処理に酸素プラズマ照射を行う場合はフォトレジストでも良い。 Next, this oxygen-terminated region is converted into a hydrogen-terminated region (S106). For this conversion process, for example, it is preferable to expose the product to hydrogen plasma for about 5 to 10 minutes. Next, of the hydrogen-terminated regions, the region to be retained as the hydrogen-terminated region is masked (S108). As the masking agent, for example, Al is used, but when oxygen plasma irradiation is performed for the oxygen termination treatment, a photoresist may be used.
次に、このマスク処理されておらず、露出した水素終端した領域を酸素終端した領域に変換処理する（Ｓ１１０）。酸素終端処理では、例えばＵＶオゾン処理や酸素プラズマ照射等を用いる。そして、マスク処理された水素終端した領域のマスク剤を除去する（Ｓ１１２）。マスク剤としてＡｌを使用する場合は、ＴＭＡＨ（水酸化テトラメチルアンモニウム）のようなエッチング剤を用いてマスク剤を除去する。 Next, the exposed hydrogen-terminated region that has not been masked is converted into an oxygen-terminated region (S110). In the oxygen termination treatment, for example, UV ozone treatment, oxygen plasma irradiation, or the like is used. Then, the masking agent in the hydrogen-terminated region that has been masked is removed (S112). When Al is used as the masking agent, the masking agent is removed by using an etching agent such as TMAH (tetramethylammonium hydroxide).
続いて、この酸素終端領域のうち酸素終端側電極となる領域にＣａを含む電極金属層を積層する（Ｓ１１４）。Ｃａを含む電極金属層としては、Ｃａを保護するためと金線をボンディングするために、Ｃａの上にＡｌ、Ｔｉ、Ａｕを積むのが良い。そして、電極金属層を積層する工程の後に、封止用のＡｌ２Ｏ３膜の成膜処理をする（Ｓ１１６）。この封止膜を設けることで、電流印加時の経時的な劣化（抵抗増加）を防止できる。 Subsequently, an electrode metal layer containing Ca is laminated on the region of the oxygen termination region that serves as the oxygen termination side electrode (S114). As the electrode metal layer containing Ca, it is preferable to stack Al, Ti, and Au on Ca in order to protect Ca and bond the gold wire. Then, after the step of laminating the electrode metal layers, a film forming process of an Al 2 O 3 film for sealing is performed (S116). By providing this sealing film, deterioration over time (increased resistance) when a current is applied can be prevented.
図３は、本発明の他の実施の形態によるダイヤモンド発光素子の製造工程のフローチャートである。ここでは、水素終端側電極となる領域に仕事関数の高い金属であるＡｕ、Ｐｄ、Ｐｔを電極材料として蒸着した場合を示している。水素終端側は仕事関数が高い金属の方が、オーミックになりやすく、好ましい。また、Ａｕ、Ｐｄ、Ｐｔなどの金属は、蒸着するだけ（加熱処理することなく）、水素終端面の表面伝導とオーミックコンタクトが取れるので、製造工程が省エネルギーとなる。 FIG. 3 is a flowchart of a manufacturing process of a diamond light emitting device according to another embodiment of the present invention. Here, a case is shown in which Au, Pd, and Pt, which are metals having a high work function, are vapor-deposited as electrode materials in the region to be the hydrogen termination side electrode. On the hydrogen termination side, a metal having a high work function is preferable because it tends to be ohmic. Further, metals such as Au, Pd, and Pt can make ohmic contact with the surface conduction of the hydrogen terminal surface only by vapor deposition (without heat treatment), which saves energy in the manufacturing process.
まず、水素終端した領域を表面に有するダイヤモンドを準備する（Ｓ２００）。次に、この水素終端領域のうち水素終端側電極となる領域にＡｕ、Ｐｄ、Ｐｔの少なくとも一種類を含む金属層を積層する（Ｓ２０２）。続いて、この水素終端した領域のうち、水素終端した領域として保持すべき領域をマスクする（Ｓ２０４）。このマスク剤としては、例えばＡｌを用いるが、酸素終端処理に酸素プラズマ照射を行う場合はフォトレジストでも良い。 First, a diamond having a hydrogen-terminated region on its surface is prepared (S200). Next, a metal layer containing at least one of Au, Pd, and Pt is laminated on the region of the hydrogen termination region that serves as the hydrogen termination side electrode (S202). Subsequently, of the hydrogen-terminated regions, the region to be retained as the hydrogen-terminated region is masked (S204). As the masking agent, for example, Al is used, but when oxygen plasma irradiation is performed for the oxygen termination treatment, a photoresist may be used.
このマスク処理されておらず、露出した水素終端した領域を酸素終端した領域に変換処理する（Ｓ２０６）。酸素終端処理では、例えばＵＶオゾン処理や酸素プラズマ照射等を用いる。次に、マスク処理された水素終端した領域のマスク剤を除去する（Ｓ２０８）。マスク剤としてＡｌを使用する場合は、ＴＭＡＨ（水酸化テトラメチルアンモニウム）のようなエッチング剤を用いてマスク剤を除去する。 This unmasked and exposed hydrogen-terminated region is converted to an oxygen-terminated region (S206). In the oxygen termination treatment, for example, UV ozone treatment, oxygen plasma irradiation, or the like is used. Next, the masking agent for the masked hydrogen-terminated region is removed (S208). When Al is used as the masking agent, the masking agent is removed by using an etching agent such as TMAH (tetramethylammonium hydroxide).
次に、この酸素終端領域のうち酸素終端側電極となる領域にＣａを含む電極金属層を積層する（Ｓ２１０）。Ｃａを含む電極金属層としては、Ｃａを保護するためと金線をボンディングするために、Ｃａの上にＡｌ、Ｔｉ、Ａｕを積むのが良い。そして、電極金属層を積層する工程の後に、封止用のＡｌ２Ｏ３膜の成膜処理をする（Ｓ２１２）。この封止膜を設けることで、電流印加時の経時的な劣化（抵抗増加）を防止できる。 Next, an electrode metal layer containing Ca is laminated on the region of the oxygen termination region that serves as the oxygen termination side electrode (S210). As the electrode metal layer containing Ca, it is preferable to stack Al, Ti, and Au on Ca in order to protect Ca and bond the gold wire. Then, after the step of laminating the electrode metal layers, a film forming process of an Al 2 O 3 film for sealing is performed (S212). By providing this sealing film, deterioration over time (increased resistance) when a current is applied can be prevented.
１．１ ダイヤモンド表面の前処理
ＩＩａ型単結晶ダイヤモンド（エレメントシックス社製ＣＶＤダイヤモンド、スタンダードグレード、面方位（１００）、２．５×２．５×０．３ｍｍ；窒素濃度１ｐｐｍ以下、ボロン濃度０．０５ｐｐｍ以下）の表面を研磨したものを、ＣＶＤ装置（アステックス社製を改造）に入れ、水素プラズマに１時間晒す。（水素ガス流量４００ｓｃｃｍ(standard cubic centimeter per minute)、３５Ｔｏｒｒ）その後、ＵＶオゾンクリーナー（サムコ社ＵＶ-1）を使い、ＵＶオゾン処理を１時間行う。ここでは面方位（１００）の単結晶ダイヤモンドを使用したが、（１１１）など異なる面方位でも良い。
1.1 Diamond surface pretreatment IIa type single crystal diamond (CVD diamond manufactured by Element Six, standard grade, plane orientation (100), 2.5 x 2.5 x 0.3 mm; nitrogen concentration 1 ppm or less, boron concentration 0 The polished surface (0.05 ppm or less) is placed in a CVD device (modified from Astex) and exposed to hydrogen plasma for 1 hour. (Hydrogen gas flow rate 400 sccm (standard cubic centimeter per minute), 35 Torr) Then, UV ozone treatment is performed for 1 hour using a UV ozone cleaner (UV-1 of SAMCO Corporation). Here, a single crystal diamond having a plane orientation (100) is used, but a different plane orientation such as (111) may be used.
１．２ 水素終端側電極の作製
ダイヤモンド表面にレジストＬＯＲ５Ａをスピンコートし１８０℃で５分ベークする。その後、フォトレジストＡＺ５２１４Ｅをスピンコートし１１０℃で２分ベークする。レーザー露光装置（ナノシステムソリューションズ社ＤＬ−１０００）によって、水素終端側の電極パターンを描画する。ＴＭＡＨ（テトラメチルアンモニウムハイドロオキサイド）２．３８％で９０秒現像し、蒸留水で３０秒洗浄の後、窒素ガスでブローする。スパッタ装置（ビームトロン社）によって、Ｔｉ５０ｎｍ／Ｐｔ５０ｎｍ／Ａｕ２００ｎｍ／Ｐｔ３０ｎｍ／Ｔｉ５ｎｍ／ＳｉＯ２ ５０ｎｍを成膜する。８０℃のＮＭＰ（Ｎ-メチルピロリドン）に１時間浸したあと、アセトン、イソプロピルアルコールに浸し、窒素ガスでブローすることでリフトオフを行う。ＡｒあるいはＨ２ガス雰囲気下で、４５０℃で３０分間加熱し、Ｔｉとダイヤモンドの境界にＴｉＣを形成させる。これにより、水素終端側のオーミック電極が形成される。
ＴｉＣの代わりに、水素終端面の表面伝導とオーミックコンタクトの取れるＡｕ、Ｐｄ、Ｐｔなどの金属を蒸着するだけ（加熱しない）でも良い。
1.2 Preparation of hydrogen-terminated electrode The resist LOR5A is spin-coated on the diamond surface and baked at 180 ° C. for 5 minutes. Then, photoresist AZ5214E is spin-coated and baked at 110 ° C. for 2 minutes. The electrode pattern on the hydrogen termination side is drawn by a laser exposure device (DL-1000 manufactured by Nanosystem Solutions Co., Ltd.). Develop with TMAH (tetramethylammonium hydroxide) 2.38% for 90 seconds, wash with distilled water for 30 seconds, and then blow with nitrogen gas. The sputtering apparatus (beam Tron Inc.), forming a Ti50nm / Pt50nm / Au200nm / Pt30nm / Ti5nm / SiO 2 50nm. After soaking in NMP (N-methylpyrrolidone) at 80 ° C. for 1 hour, it is soaked in acetone or isopropyl alcohol and blown with nitrogen gas to lift off. In an Ar or H 2 gas atmosphere, heat at 450 ° C. for 30 minutes to form TiC at the boundary between Ti and diamond. As a result, an ohmic electrode on the hydrogen termination side is formed.
Instead of TiC, a metal such as Au, Pd, or Pt that can make ohmic contact with the surface conduction of the hydrogen termination surface may be simply deposited (not heated).
１．３ 水素終端形成
上記ＣＶＤ装置にて、水素プラズマに１０分間晒し、ダイヤモンド表面を水素終端化する。
1.3 Hydrogen termination formation In the above CVD apparatus, the diamond surface is hydrogen-terminated by exposing it to hydrogen plasma for 10 minutes.
１．４ 酸素終端形成
１．２と同様のレーザーリソグラフィーによって、酸素終端しない部分のパターンを描画する。１．２と同様に現像をしたあと、電子銃型蒸着装置（エイコーエンジニアリング社）によってＡｌ１００ｎｍを成膜する。１．２と同様にリフトオフを行う。ＵＶオゾンクリーナー（サムコ社ＵＶ-1）を使い、ＵＶオゾン処理を１時間行うことで、Ａｌによってマスクされていないダイヤモンド表面を酸素終端化させる。マスクとして使ったＡｌはＴＭＡＨ２．３８％でエッチングして除去する。
酸素終端化の方法は、このようなＵＶオゾン処理に限らない。酸素プラズマ照射等によっても可能である。
1.4 Oxygen termination formation The pattern of the non-oxygen termination part is drawn by the same laser lithography as in 1.2. After developing in the same manner as in 1.2, Al 100 nm is formed by an electron gun type vapor deposition apparatus (Eiko Engineering Co., Ltd.). Lift off in the same way as in 1.2. The surface of diamond not masked by Al is oxygen-terminated by performing UV ozone treatment for 1 hour using a UV ozone cleaner (UV-1 manufactured by SAMCO Corporation). Al used as a mask is removed by etching with TMAH 2.38%.
The method of oxygen termination is not limited to such UV ozone treatment. It is also possible by oxygen plasma irradiation or the like.
１．５ 酸素終端側電極の作製
１．２と同様のレーザーリソグラフィーによって、酸素終端側の電極パターンを描画する。１．２と同様に現像する。真空蒸着装置にてＣａを成膜する。Ｃａの保護のため真空を破らずに連続してＡｌを成膜する。Ａｌの上にさらにＴｉおよびＡｕを蒸着する。電子を注入するために仕事関数の低いＣａを酸素終端側の電極材料として選んだが、これに限らない。
酸素終端領域の抵抗値を下げて動作電圧を下げるため、水素終端領域と酸素終端領域の境界から酸素終端側電極までの距離は１〜１０μｍ程度と短くすることが望ましい。水素終端領域の抵抗値を下げるため、水素終端領域と酸素終端領域の境界から水素終端側電極までの距離も短くすることが望ましい。
1.5 Preparation of oxygen-terminated electrode The electrode pattern on the oxygen-terminated side is drawn by the same laser lithography as in 1.2. Develop in the same way as in 1.2. Ca is deposited with a vacuum vapor deposition apparatus. To protect Ca, Al is continuously formed without breaking the vacuum. Ti and Au are further deposited on Al. Ca, which has a low work function, was selected as the electrode material on the oxygen termination side in order to inject electrons, but it is not limited to this.
In order to lower the resistance value of the oxygen termination region and lower the operating voltage, it is desirable that the distance from the boundary between the hydrogen termination region and the oxygen termination region to the oxygen termination side electrode be as short as about 1 to 10 μm. In order to reduce the resistance value of the hydrogen termination region, it is desirable to shorten the distance from the boundary between the hydrogen termination region and the oxygen termination region to the hydrogen termination side electrode.
１．６ 封止用のＡｌ２Ｏ３膜の成膜
表面を封止するために原子層堆積装置（Picosun社、SUNALE R-100B）によって、Ａｌ２Ｏ３ ３０ｎｍを成膜する。
1.6 Formation of Al 2 O 3 film for sealing Al 2 O 3 30 nm is formed by an atomic layer deposition device (Picosun, SUNALE R-100B) to seal the surface.
次に、上記の製造工程で製造したダイヤモンド発光素子の物理的な特性について説明する。図４は、ダイヤモンド表面に隣接して形成された水素終端の領域と酸素終端の領域のエネルギー分布を示す図である。表面終端の違いによる内蔵電位差は、伝導帯と価電子帯の両方とも、水素終端の領域と酸素終端の領域との間で、３ｅＶである。伝導帯と価電子帯とのバンドギャップは、５．４７ｅＶである。本発明のダイヤモンド発光素子では、水素終端の領域と酸素終端の領域をダイヤモンド表面に隣接して形成することによって、ｐｎ接合と同様の内蔵電位差を生じさせ、発光整流素子を実現している。 Next, the physical characteristics of the diamond light emitting device manufactured in the above manufacturing process will be described. FIG. 4 is a diagram showing the energy distribution of the hydrogen-terminated region and the oxygen-terminated region formed adjacent to the diamond surface. The built-in potential difference due to the difference in surface termination is 3 eV between the hydrogen-terminated region and the oxygen-terminated region in both the conduction band and the valence band. The band gap between the conduction band and the valence band is 5.47 eV. In the diamond light emitting device of the present invention, a hydrogen-terminated region and an oxygen-terminated region are formed adjacent to the diamond surface to generate a built-in potential difference similar to that of a pn junction, and a light emitting rectifying element is realized.
次に、図５は本実施の形態のダイヤモンド発光素子における、室温での電流電圧特性を示す図である。ここで示した電圧は、水素終端側電極に正、酸素終端側電極に負の電圧をかけた場合、正とした。負の電圧印加の場合には、５０Ｖをかけても電流は１０−１１Ａより小さい。一方、正の電圧印加によって電流が増加し、５０Ｖにおいて１０−４Ａ以上である。すなわち±５０Ｖにおいて７桁以上の整流比をもつ。 Next, FIG. 5 is a diagram showing current-voltage characteristics at room temperature in the diamond light emitting device of the present embodiment. The voltage shown here was positive when a positive voltage was applied to the hydrogen-terminated electrode and a negative voltage was applied to the oxygen-terminated electrode. When a negative voltage is applied, the current is smaller than 10-11 A even when 50 V is applied. On the other hand, the current increases due to the application of a positive voltage, which is 10 -4 A or more at 50 V. That is, it has a rectification ratio of 7 digits or more at ± 50 V.
正の電圧印加時に観測された２２０−７００ｎｍの波長範囲の発光スペクトルを図６に示す。深紫外領域の２３５ｎｍの自由励起子再結合による発光ピークが見られる。３８９、５３３、５７５ｎｍなどのピークおよび５００ｎｍ以上のブロードなピークは、ダイヤモンド中の窒素に由来するものである。より窒素濃度の低いダイヤモンドを使って素子を作製することで、これらの発光を抑え、深紫外発光の効率を高めることも可能である（第二の実施例参照）。
逆に、窒素に由来する欠陥（例えば窒素−空孔欠陥）からの発光を、本発明の発光整流素子の構造を使って積極的に制御することも可能である。窒素-空孔欠陥からの発光は、量子情報処理などの応用が考えられる単一光子源として利用可能である［非特許文献３参照］。
The emission spectrum in the wavelength range of 220-700 nm observed when a positive voltage is applied is shown in FIG. An emission peak due to free exciton recombination at 235 nm in the deep ultraviolet region can be seen. Peaks such as 389, 533, 575 nm and broad peaks above 500 nm are derived from nitrogen in diamond. By manufacturing the device using diamond having a lower nitrogen concentration, it is possible to suppress these emissions and increase the efficiency of deep ultraviolet emission (see the second embodiment).
On the contrary, it is also possible to positively control the light emission from defects derived from nitrogen (for example, nitrogen-vacancy defects) by using the structure of the light emission rectifying element of the present invention. Emission from nitrogen-vacancy defects can be used as a single photon source that can be applied to quantum information processing and the like [see Non-Patent Document 3].
以下、本発明の第二の実施例について説明する。
第一の実施例で使用したダイヤモンドに比べてより窒素およびボロン濃度の低い以下に示すダイヤモンドを使って、発光整流素子を作製した。使用したダイヤモンドは、ＩＩａ型単結晶ダイヤモンド（エレメントシックス社 ＣＶＤダイヤモンド エレクトロニックグレード 面方位（１００）２．０×２．０×０．５ｍｍ; 窒素濃度５ｐｐｂ以下、ボロン濃度１ｐｐｂ以下）である。作製方法は、第一の実施例のレーザーリソグラフィーを電子線リソグラフィーに代えたこと以外は、第一の実施例と同様である。電子線リソグラフィーは以下のように行った。ダイヤモンド表面にレジストＰＭＧＩ−ＳＦ６ｓをスピンコートし１８０℃で５分ベークする。その後、レジストｇｌ２０００−８をスピンコートし１８０℃で５分ベークする。その後、帯電防止用のエスペイサー３００Ｚをスピンコートし、１１０℃で１分ベークする。電子ビーム描画装置（エリオニクス社ＥＬＳ−Ｆ１２５）によって、電極パターン等を描画する。蒸留水に１分浸しエスペイサーを除去したのち、キシレンで６０秒現像し、蒸留水で３０秒洗浄の後、窒素ガスでブローする。その後、ＴＭＡＨ（テトラメチルアンモニウムハイドロオキサイド）２．３８％に３０秒浸しＰＭＧＩ−ＳＦ６ｓをエッチングし、蒸留水で３０秒洗浄の後、窒素ガスでブローする。
Hereinafter, a second embodiment of the present invention will be described.
The emission rectifying element was manufactured using the diamonds shown below, which have lower nitrogen and boron concentrations than the diamond used in the first example. The diamond used was a type IIa single crystal diamond (element six company CVD diamond electronic grade plane orientation (100) 2.0 × 2.0 × 0.5 mm; nitrogen concentration 5 ppb or less, boron concentration 1 ppb or less). The manufacturing method is the same as that of the first embodiment except that the laser lithography of the first embodiment is replaced with the electron beam lithography. The electron beam lithography was performed as follows. The surface of the diamond is spin-coated with resist PMGI-SF6s and baked at 180 ° C. for 5 minutes. Then, resist gl2000-8 is spin-coated and baked at 180 ° C. for 5 minutes. Then, the antistatic Espacer 300Z is spin-coated and baked at 110 ° C. for 1 minute. An electrode pattern or the like is drawn by an electron beam drawing device (ELS-F125 manufactured by Elionix Inc.). After immersing in distilled water for 1 minute to remove the espacer, it is developed with xylene for 60 seconds, washed with distilled water for 30 seconds, and then blown with nitrogen gas. Then, it is immersed in TMAH (tetramethylammonium hydroxide) 2.38% for 30 seconds to etch PMGI-SF6s, washed with distilled water for 30 seconds, and then blown with nitrogen gas.
作製した発光整流素子の室温における電流電圧特性を図７に示す。図５と同様に電圧は、水素終端側電極に正、酸素終端側電極に負の電圧をかけた場合、正とした。負の電圧印加の場合には、電流はおよそ３×１０−１３Ａ以下である。一方、正の電圧印加によって電流が増加し、１０Ｖにおいて７×１０−４Ａである。すなわち±１０Ｖにおいて９桁以上の整流比をもつ。
正の電圧印加時に観測された２２０−７００ｎｍの波長範囲の発光スペクトルを図８に示す。深紫外領域の２３５ｎｍの自由励起子再結合による発光ピークが見られる。第一の実施例に比べて、可視域の発光が小さい。これは、第一の実施例に比べてより低い不純物濃度のダイヤモンドを使用したことによる。
The current-voltage characteristics of the manufactured light-emitting rectifying element at room temperature are shown in FIG. Similar to FIG. 5, the voltage was positive when a positive voltage was applied to the hydrogen terminal electrode and a negative voltage was applied to the oxygen terminal electrode. When a negative voltage is applied, the current is approximately 3 × 10 -13 A or less. On the other hand, the current is increased by applying a positive voltage, which is 7 × 10 -4 A at 10 V. That is, it has a rectification ratio of 9 digits or more at ± 10 V.
The emission spectrum in the wavelength range of 220-700 nm observed when a positive voltage is applied is shown in FIG. An emission peak due to free exciton recombination at 235 nm in the deep ultraviolet region can be seen. Compared to the first embodiment, the light emission in the visible region is small. This is due to the use of diamond with a lower impurity concentration than in the first embodiment.
なお、上記の本発明の実施の形態においては、水素終端と酸素終端の組合せを例に説明したが、本発明はこれに限定されるものではなく、例えば酸素終端の代わりに、酸素以上に電気陰性度の大きなフッ素を使ったフッ素終端を用いても良い。 In the above-described embodiment of the present invention, the combination of hydrogen termination and oxygen termination has been described as an example, but the present invention is not limited to this, and for example, instead of oxygen termination, electricity is higher than oxygen. Fluorine termination using fluorine with a high electronegativity may be used.
また、水素終端および酸素終端の領域の形状には大きな自由度がある。円形状の素子にすることも、また櫛形にすることも可能である。さらに、水素終端および酸素終端の形状により、微小な領域に発光を制限することもできる。これにより、量子情報処理への応用が可能なダイヤモンド中の単一の窒素−空孔欠陥からの発光を電流注入によって行うことも原理的には可能である。また、櫛形構造において、水素終端と酸素終端の領域の周期を微細化することにより、発光面密度を高めることも可能である。 In addition, there is a great degree of freedom in the shape of the hydrogen-terminated and oxygen-terminated regions. It can be a circular element or a comb shape. Furthermore, the shape of hydrogen termination and oxygen termination can also limit light emission to minute regions. This makes it possible in principle to emit light from a single nitrogen-vacancy defect in diamond, which can be applied to quantum information processing, by current injection. Further, in the comb-shaped structure, it is possible to increase the light emitting surface density by miniaturizing the period of the hydrogen-terminated and oxygen-terminated regions.
本発明のダイヤモンド発光素子は、高密度光記録や微細加工、殺菌、環境汚染物質の分解、情報処理などに利用可能である。 The diamond light emitting device of the present invention can be used for high-density optical recording, fine processing, sterilization, decomposition of environmental pollutants, information processing, and the like.
１ 水素終端の領域
２ 酸素終端の領域
３ 水素終端側電極
４ 酸素終端側電極
５ 単結晶ダイヤモンド
1 Hydrogen-terminated region 2 Oxygen-terminated region 3 Hydrogen-terminated electrode 4 Oxygen-terminated electrode 5 Single crystal diamond
Claims (7)
当該水素終端した領域に隣接すると共に、前記ダイヤモンドの表面を酸素で終端した領域、
当該水素終端した領域に設けられた水素終端側電極、
当該酸素終端した領域に設けられた酸素終端側電極とを備え、
前記水素終端側電極に正の電圧、前記酸素終端側電極に負の電圧を印加した場合に、前記水素終端側電極から前記酸素終端側電極の方向に流れる電流を順方向とする、整流特性を示すと共に、
前記当該水素終端した領域と前記酸素終端を前記ダイヤモンドの表面に隣接して形成された領域であって、前記当該水素終端した領域のうち前記水素終端側電極で覆われていない領域と、前記酸素終端した領域のうち前記酸素終端側電極で覆われていない領域との境界領域で発光することを特徴とするダイヤモンド発光素子。 A region where the surface of a non-doped diamond is terminated with hydrogen,
A region adjacent to the hydrogen-terminated region and oxygen-terminated on the surface of the diamond,
Hydrogen-terminated electrodes provided in the hydrogen-terminated region,
It is provided with an oxygen-terminated electrode provided in the oxygen-terminated region.
When a positive voltage is applied to the hydrogen-terminated electrode and a negative voltage is applied to the oxygen-terminated electrode, the current flowing from the hydrogen-terminated electrode to the oxygen-terminated electrode is in the forward direction. As well as showing
A region formed by adjoining the hydrogen-terminated region and the oxygen-terminated region on the surface of the diamond, and the region of the hydrogen-terminated region not covered by the hydrogen-terminated electrode, and the oxygen. A diamond light emitting element that emits light in a region that is a boundary region between the terminated regions and a region that is not covered by the oxygen terminal side electrode.
前記ダイヤモンドの表面であって、当該水素終端した領域に隣接したフッ素で終端した領域、
当該水素終端した領域に設けられた水素終端側電極、
当該フッ素終端した領域に設けられたフッ素終端側電極とを備え、
前記水素終端側電極に正の電圧、前記酸素終端側電極に負の電圧を印加した場合に、前記水素終端側電極から前記酸素終端側電極の方向に流れる電流を順方向とする、整流特性を示すと共に、
前記水素終端側電極に正の電圧、前記フッ素終端側電極に負の電圧を印加した場合に、前記水素終端側電極から前記フッ素終端側電極の方向に流れる電流を順方向とする、整流特性を示すと共に、
前記当該水素終端した領域と前記フッ素終端を前記ダイヤモンドの表面に隣接して形成された領域であって、前記当該水素終端した領域のうち前記水素終端側電極で覆われていない領域と、前記フッ素終端した領域のうち前記フッ素終端側電極で覆われていない領域との境界領域で発光することを特徴とするダイヤモンド発光素子。 A region where the surface of a non-doped diamond is terminated with hydrogen,
A fluorine-terminated region on the surface of the diamond that is adjacent to the hydrogen-terminated region.
Hydrogen-terminated electrodes provided in the hydrogen-terminated region,
It is provided with a fluorine-terminated electrode provided in the fluorine-terminated region.
When a positive voltage is applied to the hydrogen-terminated electrode and a negative voltage is applied to the oxygen-terminated electrode, the current flowing from the hydrogen-terminated electrode to the oxygen-terminated electrode is in the forward direction. As well as showing
Positive voltage to the hydrogen termination side electrode, in the case of applying a negative voltage to the fluorine termination side electrode, the current flowing from the hydrogen termination side electrode in the direction of the fluorine terminating side electrode and the forward direction, the rectifying characteristics As well as showing
A region formed by adjoining the hydrogen-terminated region and the fluorine- terminated region on the surface of the diamond, and the region of the hydrogen-terminated region not covered by the hydrogen-terminated electrode, and the fluorine. A diamond light emitting element that emits light in a region boundary with a region that is not covered by the fluorine terminal electrode in the terminated region.
酸素終端した領域を表面に有する、ノンドープのダイヤモンドを準備する工程と、
この酸素終端領域のうち水素終端側電極となる領域に金属層（Ｔｉ）を積層する工程と、
この金属層を加熱処理して、当該金属層と前記ダイヤモンドとの境界に炭化金属層（ＴｉＣ）を形成してオーミック電極を形成する工程と、
この酸素終端領域を水素終端した領域に変換処理する工程と、
この水素終端した領域のうち、水素終端した領域として保持すべき領域をマスクする工程と、
このマスク処理されておらず、露出した水素終端した領域を酸素終端した領域に変換処理する工程と、
前記マスク処理された水素終端した領域のマスク剤を除去する工程と、
この酸素終端領域のうち酸素終端側電極となる領域に、Ｃａ、Ｍｇ、Ｂａ、Ｙ、Ａｌの少なくとも一種類を含む電極金属層を積層する工程と、
を有することを特徴とするダイヤモンド発光素子の製造方法。 The method for manufacturing a diamond light emitting device according to any one of claims 1 to 3.
The process of preparing a non-doped diamond with an oxygen-terminated region on its surface, and
A step of laminating a metal layer (Ti) on a region of the oxygen termination region that serves as a hydrogen termination side electrode, and
A step of heat-treating this metal layer to form a carbide layer (TiC) at the boundary between the metal layer and the diamond to form an ohmic electrode.
The process of converting this oxygen-terminated region into a hydrogen-terminated region, and
Of this hydrogen-terminated region, the step of masking the region to be retained as the hydrogen-terminated region, and
The process of converting the exposed hydrogen-terminated region to the oxygen-terminated region, which is not masked,
The step of removing the masking agent in the masked hydrogen-terminated region, and
A step of laminating an electrode metal layer containing at least one of Ca, Mg, Ba, Y, and Al on a region of the oxygen termination region that serves as an oxygen termination side electrode.
A method for manufacturing a diamond light emitting device.
水素終端した領域を表面に有する、ノンドープのダイヤモンドを準備する工程と、
この水素終端領域のうち水素終端側電極となる領域にＡｕ、Ｐｄ、Ｐｔの少なくとも一種類を含む金属層を積層する工程と、
この水素終端した領域のうち、水素終端した領域として保持すべき領域をマスクする工程と、
このマスク処理されておらず、露出した水素終端した領域を酸素終端した領域に変換処理する工程と、
前記マスク処理された水素終端した領域のマスク剤を除去する工程と、
この酸素終端領域のうち酸素終端側電極となる領域に、Ｃａ、Ｍｇ、Ｂａ、Ｙ、Ａｌの少なくとも一種類を含む電極金属層を積層する工程と、
を有することを特徴とするダイヤモンド発光素子の製造方法。 The method for manufacturing a diamond light emitting device according to any one of claims 1 to 3.
The process of preparing a non-doped diamond with a hydrogen-terminated region on its surface,
A step of laminating a metal layer containing at least one of Au, Pd, and Pt in a region of the hydrogen termination region that serves as a hydrogen termination side electrode, and
Of this hydrogen-terminated region, the step of masking the region to be retained as the hydrogen-terminated region, and
The process of converting the exposed hydrogen-terminated region to the oxygen-terminated region, which is not masked,
The step of removing the masking agent in the masked hydrogen-terminated region, and
A step of laminating an electrode metal layer containing at least one of Ca, Mg, Ba, Y, and Al on a region of the oxygen termination region that serves as an oxygen termination side electrode.
A method for manufacturing a diamond light emitting device.
Further, after the step of stacking the electrode metal layer, a step of the deposition process of the Al 2 O 3 film for sealing the area including the oxygen-terminated side electrode and the hydrogen-terminated regions and the oxygen-terminated regions The method for manufacturing a diamond light emitting element according to claim 5 or 6, wherein the diamond light emitting element is included.
Priority Applications (1)
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