JP2012019083A - Quantum dot type infrared ray detection element, and quantum dot type infrared ray imaging apparatus - Google Patents

Quantum dot type infrared ray detection element, and quantum dot type infrared ray imaging apparatus Download PDF

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JP2012019083A
JP2012019083A JP2010155819A JP2010155819A JP2012019083A JP 2012019083 A JP2012019083 A JP 2012019083A JP 2010155819 A JP2010155819 A JP 2010155819A JP 2010155819 A JP2010155819 A JP 2010155819A JP 2012019083 A JP2012019083 A JP 2012019083A
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JP5302270B2 (en
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Minoru Toshida
実 土志田
Mitsuhiro Nagashima
満宏 長嶋
Michiya Kibe
道也 木部
Masatoshi Koyama
正敏 小山
Yasuhito Uchiyama
靖仁 内山
Hiroyasu Yamashita
裕泰 山下
Hiroshi Nishino
弘師 西野
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TECHNICAL RES & DEV INST MINISTRY DEFENCE
Fujitsu Ltd
Technical Research and Development Institute of Japan Defence Agency
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Fujitsu Ltd
Technical Research and Development Institute of Japan Defence Agency
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Abstract

PROBLEM TO BE SOLVED: To provide a quantum dot type infrared ray detection element and a quantum dot type infrared ray imaging apparatus to increase a photocurrent under a restriction of the number of quantum dot layers.SOLUTION: Spacer layers are provided between a quantum dot lamination structure and upper and lower electrode formation layers respectively. In the quantum dot lamination structure, a plurality of lamination structures consisting of a quantum dot layer, which consists of a plurality of quantum dots, and an interlayer, which sandwiches the quantum dot layer and has a bandgap wider than that of the quantum dot, are laminated.

Description

本発明は量子ドット構造を赤外線検出部とする量子ドット型赤外線検知素子及び量子ドット型赤外線撮像装置に関するものである。   The present invention relates to a quantum dot infrared detector and a quantum dot infrared imaging device having a quantum dot structure as an infrared detector.

近年、１０μｍ帯の赤外線を検知する赤外線検知素子として量子構造を利用した赤外線検知素子が用いられている。その中でも垂直に入射した赤外線の検知が可能な量子ドット型赤外線検知素子（Ｑｕａｎｔｕｍ Ｄｏｔ Ｉｎｆｒａｒｅｄ Ｐｈｏｔｏｄｅｔｅｃｔｏｒ；ＱＤＩＰ）が注目を集めている。   In recent years, an infrared detection element using a quantum structure has been used as an infrared detection element for detecting infrared rays in the 10 μm band. Among them, a quantum dot infrared detector (QDIP) that can detect infrared rays incident vertically is attracting attention.

このＱＤＩＰでは、ＡｌＧａＡｓ層からなる中間層に挟み込まれたＩｎＡｓ量子ドット内の伝導帯側の量子準位に位置する電子が外部から入射してきた赤外線により励起され、この電子により誘発される光電流を捕らえることで赤外線を検知している。   In this QDIP, electrons located in a quantum level on the conduction band side in an InAs quantum dot sandwiched between intermediate layers made of an AlGaAs layer are excited by infrared rays incident from the outside, and a photocurrent induced by the electrons is generated. Infrared light is detected by capturing.

量子ドットは、例えば、分子線エピタキシャル装置のなかでＧａＡｓ基板上に形成されるため、成長方向に対して垂直な面内に量子ドット層として形成される。通常、これを複数積層した量子ドット積層構造を２つのｎ型ＧａＡｓ電極層で挟み込み、赤外線により励起された電子が量子ドット積層構造より離れて電極層に到達することで、光電流を誘発する。   For example, since the quantum dots are formed on a GaAs substrate in a molecular beam epitaxial apparatus, they are formed as quantum dot layers in a plane perpendicular to the growth direction. Usually, a quantum dot laminated structure in which a plurality of these are laminated is sandwiched between two n-type GaAs electrode layers, and electrons excited by infrared rays are separated from the quantum dot laminated structure to reach the electrode layer, thereby inducing a photocurrent.

図８は、従来のＱＤＩＰの概念的断面図であり、例えば、ＩｎＡｓからなる複数の量子ドット５２で構成される量子ドット層を、量子ドット層よりもバンドギャップの大きいＡｌＧａＡｓからなる中間層５３中に埋め込んだ量子ドット積層構造５１と、量子ドット積層構造５１の上下に形成されたｎ型ＧａＡｓからなる電極形成層５４，５５によって構成される。   FIG. 8 is a conceptual cross-sectional view of a conventional QDIP. For example, a quantum dot layer composed of a plurality of quantum dots 52 composed of InAs is included in an intermediate layer 53 composed of AlGaAs having a larger band gap than the quantum dot layer. And the electrode forming layers 54 and 55 made of n-type GaAs formed above and below the quantum dot stacked structure 51.

また、各電極形成層５４，５５には、それぞれ電極が形成され、赤外線を検知する際には、電極形成層５４，５５を介して電源により量子ドット積層構造５１に電圧を印加する。   In addition, electrodes are formed on the electrode forming layers 54 and 55, respectively, and when detecting infrared rays, a voltage is applied to the quantum dot stacked structure 51 by a power source via the electrode forming layers 54 and 55.

図９は、赤外線検知原理の説明図であり、図９（ａ）は赤外線の入射のない場合の暗電流を示し、図９（ｂ）は、赤外線が入射した場合の光電流を示している。まず、図９（ａ）に示すように、量子ドット５２の伝導帯側量子準位５６には電極形成層５４，５５などから電子５７が供給される。その結果、量子ドット積層構造５１では平均空間電荷が負となり、伝導帯形状が上に凸状となる。   FIG. 9 is an explanatory diagram of the principle of infrared detection, FIG. 9 (a) shows the dark current when no infrared light is incident, and FIG. 9 (b) shows the photocurrent when infrared light is incident. . First, as shown in FIG. 9A, electrons 57 are supplied to the conduction band side quantum level 56 of the quantum dot 52 from the electrode formation layers 54 and 55 and the like. As a result, in the quantum dot laminated structure 51, the average space charge is negative, and the conduction band shape is convex upward.

量子ドット積層構造５１の伝導帯下端の最高点が陰極側の電極形成層５４に位置する電子５８にとって障壁となるが、この障壁より高いエネルギーをもつ電子５９は障壁を通過してもう一方の陽極側の電極形成層５５に到達し、電極形成層間を流れる暗電流となる。   The highest point at the lower end of the conduction band of the quantum dot stacked structure 51 becomes a barrier for the electrons 58 located in the electrode forming layer 54 on the cathode side, but the electrons 59 having energy higher than this barrier pass through the barrier and pass through the other anode. It reaches the electrode forming layer 55 on the side and becomes a dark current flowing between the electrode forming layers.

図９（ｂ）に示すように、ここに赤外線６０が入射し、励起された電子５７が量子ドット積層構造５１から離れて電極形成層５５に到達すると、量子ドット積層構造５１では平均空間電荷が電子１個分正に傾く。   As shown in FIG. 9B, when the infrared ray 60 is incident on the excited electron 57 and leaves the quantum dot stacked structure 51 and reaches the electrode forming layer 55, the quantum dot stacked structure 51 has an average space charge. Tilt positive by one electron.

その結果、伝導帯形状は上に凸状となる度合いが小さくなることから障壁は低くなり、これを通過することのできる電子５９，６１が増えるために電流が増加し、この増加電流分が光電流として誘発されることとなる。   As a result, the conduction band shape becomes less convex so that the barrier becomes lower, and the number of electrons 59 and 61 that can pass therethrough increases. As a result, the current increases, and this increased current is reflected by light. It will be induced as an electric current.

ＱＤＩＰをはじめとする赤外線検知素子の性能は概ね光電流で決まるため、光電流を増加させることが高性能な赤外線検知素子を実現するために重要となる。そこで、光電流を増加させる手法として、量子ドット層の層数を増やす手法がよく用いられる（例えば、特許文献１参照）。   Since the performance of infrared detection elements such as QDIP is generally determined by the photocurrent, increasing the photocurrent is important for realizing a high-performance infrared detection element. Therefore, as a method of increasing the photocurrent, a method of increasing the number of quantum dot layers is often used (see, for example, Patent Document 1).

特開２００８−１９８６７７公報JP 2008-198677 A

しかし、量子ドットは基板に対して格子整合しない材料を用いて形成されることから、層数を増やすに従い歪の蓄積が起こる。歪の蓄積は量子ドットの不所望な形成や転位欠陥の発生などを引き起こすため、光電流の増加が望めないばかりでなく暗電流の増加などによる性能劣化を招くという問題がある。このことから層数の上限がある程度制限される。   However, since the quantum dots are formed using a material that is not lattice-matched to the substrate, accumulation of strain occurs as the number of layers increases. Accumulation of strain causes undesired formation of quantum dots, generation of dislocation defects, and the like. Therefore, there is a problem that not only increase in photocurrent can be expected, but also performance deterioration due to increase in dark current occurs. This limits the upper limit of the number of layers to some extent.

したがって、本発明は、量子ドット層の層数が制限される制約のなかで光電流を増加させることを目的とする。   Accordingly, an object of the present invention is to increase the photocurrent within the constraint that the number of quantum dot layers is limited.

開示される一観点からは、複数の量子ドットからなる量子ドット層と前記量子ドット層を挟み込むとともに前記量子ドットよりバンドギャップが広い中間層からなる積層構造を複数積層した量子ドット積層構造と、前記量子ドット積層構造を挟み込む上下のスペーサ層と、前記上下のスペーサ層の外側に設ける上下の電極形成層とを有する量子ドット型赤外線検知素子が提供される。   From one disclosed aspect, a quantum dot stacked structure in which a plurality of stacked structures including a quantum dot layer composed of a plurality of quantum dots and a quantum dot layer sandwiched between the quantum dots and an intermediate layer having a wider band gap than the quantum dots, There is provided a quantum dot infrared detecting element having upper and lower spacer layers sandwiching a quantum dot stacked structure and upper and lower electrode forming layers provided outside the upper and lower spacer layers.

また、開示される別の観点からは、複数の量子ドットからなる量子ドット層と前記量子ドット層を挟み込むとともに前記量子ドットよりバンドギャップが広い中間層からなる積層構造を複数積層した量子ドット積層構造と、前記量子ドット積層構造を挟み込む上下のスペーサ層と、前記上下のスペーサ層の外側に設ける上下の電極形成層とを有する量子ドット型赤外線検知素子をマトリクス状に形成するとともに、前記各量子ドット型赤外線検知素子の陽極側の電極形成層に突起状電極を設けた量子ドット型赤外線検知器と、前記各突起状電極に対応する位置に接続パッドを有するとともに、信号処理回路を備えた半導体集積回路装置とを有する量子ドット型赤外線撮像装置が提供される。   Further, from another disclosed aspect, a quantum dot stacked structure in which a plurality of stacked structures including a quantum dot layer composed of a plurality of quantum dots and an intermediate layer having a wider band gap than the quantum dots are sandwiched between the quantum dot layers And a quantum dot infrared detecting element having upper and lower spacer layers sandwiching the quantum dot stacked structure and upper and lower electrode forming layers provided outside the upper and lower spacer layers, and forming each quantum dot Quantum dot infrared detector provided with a protruding electrode on the electrode forming layer on the anode side of the infrared detecting element, and a semiconductor integrated circuit having a connection pad at a position corresponding to each protruding electrode and a signal processing circuit A quantum dot infrared imaging device having a circuit device is provided.

開示の量子ドット型赤外線検知素子及び量子ドット型赤外線撮像装置によれば、量子ドット積層構造の両側にスペーサ層を設け、量子ドット積層構造による電子に対する障壁の高さを変動を大きくしている。その結果、量子ドット層の層数が同じでも赤外線で励起された電子による光電流に誘起されて電極形成層から流れ込む光電流を増加することが可能となる。   According to the disclosed quantum dot infrared detection element and quantum dot infrared imaging device, spacer layers are provided on both sides of the quantum dot stacked structure, and the fluctuation of the height of the barrier against electrons due to the quantum dot stacked structure is increased. As a result, even if the number of quantum dot layers is the same, it is possible to increase the photocurrent flowing from the electrode formation layer by being induced by the photocurrent caused by the electrons excited by infrared rays.

本発明の実施の形態のＱＤＩＰの概念的断面図である。It is a conceptual sectional view of QDIP of an embodiment of the invention. 本発明の実施の形態における障壁変動の増加の説明図である。It is explanatory drawing of the increase in the barrier fluctuation | variation in embodiment of this invention. 光電流のスペーサ層の厚さ／量子ドット積層構造の厚さ依存性の説明図である。It is explanatory drawing of the thickness dependence of the spacer layer thickness / quantum dot laminated structure of a photocurrent. 本発明の実施例１の量子ドット型赤外線検知素子の途中までの製造工程の説明図である。It is explanatory drawing of the manufacturing process to the middle of the quantum dot type | mold infrared detection element of Example 1 of this invention. 本発明の実施例１の量子ドット型赤外線検知素子の図４以降の途中までの製造工程の説明図である。It is explanatory drawing of the manufacturing process to the middle after FIG. 4 of the quantum dot type | mold infrared detection element of Example 1 of this invention. 本発明の実施例１の量子ドット型赤外線検知素子の図５以降の製造工程の説明図である。It is explanatory drawing of the manufacturing process after FIG. 5 of the quantum dot infrared rays detection element of Example 1 of this invention. 本発明の実施例２の量子ドット型赤外線撮像装置の概念的斜視図である。It is a notional perspective view of the quantum dot type infrared imaging device of Example 2 of the present invention. 従来のＱＤＩＰの概念的断面図である。It is a conceptual sectional view of conventional QDIP. 赤外線検知原理の説明図である。It is explanatory drawing of an infrared detection principle.

ここで、図１乃至図３を参照して、本発明の実施の形態のＱＤＩＰを説明する。図１は、本発明の実施の形態のＱＤＩＰの概念的断面図である。ＱＤＩＰは、複数の量子ドット２からなる量子ドット層と、量子ドット層を挟み込み中間層３とからなる量子ドット積層構造１と、量子ドット積層構造１の上下に形成されたスペーサ層４，５と、スペーサ層４，５の上下に設けられた電極形成層６，７によって構成される。   Here, with reference to FIG. 1 thru | or FIG. 3, QDIP of embodiment of this invention is demonstrated. FIG. 1 is a conceptual cross-sectional view of a QDIP according to an embodiment of the present invention. QDIP includes a quantum dot layer structure 1 composed of a quantum dot layer composed of a plurality of quantum dots 2 and an intermediate layer 3 sandwiching the quantum dot layer, and spacer layers 4, 5 formed above and below the quantum dot layer structure 1. The electrode forming layers 6 and 7 are provided above and below the spacer layers 4 and 5, respectively.

量子ドット２は、例えば、Ｉｎ１−ｘＧａｘＡｓ（０≦ｘ＜１）からなり、また、中間層３は、量子ドット２を構成する半導体よりバンドギャップの広い厚さが３０ｎｍ以上のＡｌｙＧａ１−ｙＡｓ（０≦ｙ≦１）からなる。また、スペーサ層４，５はＡｚＧａ１−ｚＡｓ（０≦ｚ≦１）からなり、典型的にはｚ＝ｙである。また、電極形成層６，７は、例えば、ｎ型ＧａＡｓ層からなり、各電極形成層６，７には、例えば、ＡｕＧｅ／Ａｕ積層構造の電極を設ける。 The quantum dots 2 are made of, for example, In 1-x Ga x As (0 ≦ x <1), and the intermediate layer 3 is made of Al having a wider band gap than the semiconductor constituting the quantum dots 2 and having a thickness of 30 nm or more. y Ga 1-y As consists (0 ≦ y ≦ 1). The spacer layers 4 and 5 are made of A z Ga 1-z As (0 ≦ z ≦ 1), and typically z = y. The electrode forming layers 6 and 7 are made of, for example, an n-type GaAs layer, and each electrode forming layer 6 and 7 is provided with, for example, an electrode having an AuGe / Au laminated structure.

図２は、本発明の実施の形態における障壁変動の増加の説明図である。図２（ａ）は、スペーサ層を設けない従来のＱＤＩＰにおける障壁変動の説明図であり、光励起された電子の抜け出しによる電位障壁の変動はΔＥ1である。   FIG. 2 is an explanatory diagram of an increase in barrier fluctuation in the embodiment of the present invention. FIG. 2A is an explanatory diagram of the barrier fluctuation in the conventional QDIP without the spacer layer, and the fluctuation of the potential barrier due to the escape of the photoexcited electrons is ΔE1.

一方、図２（ｂ）に示すように、スペーサ層を設けた場合には、光励起された電子の抜け出しによる電位障壁の変動は、量子ドット積層構造１における変動ΔＥ１の他に、スペーサ層４，５における変動ΔＥ２も生起する。 On the other hand, as shown in FIG. 2B, when the spacer layer is provided, the fluctuation of the potential barrier due to the escape of the photoexcited electrons is caused by the spacer layer 4 in addition to the fluctuation ΔE 1 in the quantum dot stacked structure 1. also occur variations Delta] E 2 in 5.

したがって、図２（ｃ）に示すように、電極形成層６，７からみた電子の電位障壁の変動は、ΔＥ１＋ΔＥ２となり、スペーサ層４，５を設けない場合の変動ΔＥ１より、ΔＥ２だけ大きくなる。その結果、上述の図９（ｂ）に示した光励起された電子の抜け出しによる光電流に引きずられて誘起される光電流が増加することになる。 Therefore, as shown in FIG. 2C, the fluctuation of the electron potential barrier seen from the electrode forming layers 6 and 7 is ΔE 1 + ΔE 2 , and the fluctuation ΔE 1 when the spacer layers 4 and 5 are not provided is ΔE 1 . Increase by two . As a result, the photocurrent induced by being dragged by the photocurrent due to the escape of the photoexcited electrons shown in FIG. 9B increases.

図３は、光電流のスペーサ層の厚さ／量子ドット積層構造の厚さ依存性の説明図であり、ここでは、中間層３をＡｌ０.２Ｇａ０.８Ａｓで形成するとともに、スペーサ層４，５もＡｌ０.２Ｇａ０.８Ａｓで形成している。 FIG. 3 is an explanatory diagram of the dependence of the photocurrent on the thickness of the spacer layer / the thickness of the quantum dot stacked structure. Here, the intermediate layer 3 is formed of Al 0.2 Ga 0.8 As and the spacer Layers 4 and 5 are also formed of Al 0.2 Ga 0.8 As.

図３において、（ａ）で示すスペーサ層４，５を設けない従来例に比べて、スペーサ層４，５を設けた（ｂ）及び（ｃ）の場合には、光電流が増加している。したがって、実験で確認した範囲では、スペーサ層４，５の厚さの量子ドット積層構造の厚さに対する比を０．５〜１．４にすれば、確実に光電流を増大させることが可能になる。   In FIG. 3, the photocurrent is increased in the cases (b) and (c) where the spacer layers 4 and 5 are provided, as compared with the conventional example shown in FIG. 3A where the spacer layers 4 and 5 are not provided. . Therefore, within the range confirmed by the experiment, if the ratio of the thickness of the spacer layers 4 and 5 to the thickness of the quantum dot stacked structure is set to 0.5 to 1.4, the photocurrent can be reliably increased. Become.

一方、量子ドット積層構造の厚さに対するスペーサ層４，５の厚さの比を１．０とした上で中間層の厚さを２０ｎｍとした実験例では、（ａ）の従来例より光電流が低下する結果を得た。一般的な量子ドット成長において中間層の厚さが３０ｎｍを下回ると下層の量子ドット層の影響を受けて所望の量子ドットを成長することができなくなることから、この実験例ではこの影響により光電流が低下したものと考えられる。   On the other hand, in the experimental example in which the ratio of the thickness of the spacer layers 4 and 5 to the thickness of the quantum dot laminated structure is 1.0 and the thickness of the intermediate layer is 20 nm, the photocurrent is higher than that of the conventional example of (a). The result was decreased. In general quantum dot growth, if the thickness of the intermediate layer is less than 30 nm, it becomes impossible to grow a desired quantum dot due to the influence of the lower quantum dot layer. Is thought to have been reduced.

一方、中間層の厚さを３０ｎｍ以上とした実験例ではこの影響がみられていないことから、スペーサ層の厚さの量子ドット積層構造の厚さに対する比に加えて、中間層の厚さとして３０ｎｍ以上とすることが、本発明を有効なものとする。なお、上下両端の量子ドット層はスペーサ層と中間層で挟まれることになるが、本発明における「量子ドット積層構造」の厚さは、実効的に中間層の総和の厚さになる。   On the other hand, since this effect is not seen in the experimental example in which the thickness of the intermediate layer is 30 nm or more, in addition to the ratio of the spacer layer thickness to the thickness of the quantum dot stacked structure, The thickness of 30 nm or more makes the present invention effective. In addition, although the quantum dot layers at the upper and lower ends are sandwiched between the spacer layer and the intermediate layer, the thickness of the “quantum dot stacked structure” in the present invention is effectively the total thickness of the intermediate layers.

以上を前提として、次に、図４乃至図７を参照して、本発明の実施例１の量子ドット型赤外線検知素子を説明する。まず、図４（ａ）に示すように、例えば、分子線エピタキシャル法により、半絶縁性ＧａＡｓ基板１１上に、基板温度を例えば６００℃として下部電極形成層となる厚さが、例えば、１μｍのｎ型ＧａＡｓ層１２を成長させる。この場合のｎ型ドーパントとして例えばＳｉを用い、その濃度は例えば２×１０18ｃｍ-3とする。 Based on the above, the quantum dot infrared detection element of Example 1 of the present invention will be described next with reference to FIGS. First, as shown in FIG. 4A, the thickness of the lower electrode formation layer is set to, for example, 1 μm on the semi-insulating GaAs substrate 11 at a substrate temperature of, eg, 600 ° C. by, for example, molecular beam epitaxy. An n-type GaAs layer 12 is grown. In this case, for example, Si is used as the n-type dopant, and its concentration is set to 2 × 10 18 cm −3 , for example.

引き続いて、図４（ｂ）に示すように、ｎ型ＧａＡｓ層１２上に厚さが、例えば、１４０ｎｍで、Ａｌ組成比が０．２のｉ型Ａｌ０.２Ｇａ０.８Ａｓスペーサ層１３を成長させる。 Subsequently, as shown in FIG. 4B, an i-type Al 0.2 Ga 0.8 As spacer layer having a thickness of, for example, 140 nm and an Al composition ratio of 0.2 on the n-type GaAs layer 12. Grow 13

次いで、基板温度を６００℃から自己組織化形成の起こり得る温度、例えば、５００℃に降温したのち、図４（ｃ）に示すように、成長速度を例えば、０．２原子層／秒としてＩｎＡｓを２．０原子層分供給することによってＩｎＡｓ量子ドット１４を形成する。この時、ＩｎＡｓを供給する過程で、ある程度の量を供給することによりＩｎＡｓに加わる圧縮歪が増し、ＩｎＡｓが３次元成長をしてＩｎＡｓ量子ドット１４が自己組織化形成され、この複数のＩｎＡｓ量子ドット１４の集合体が量子ドット層となる。   Next, after the substrate temperature is lowered from 600 ° C. to a temperature at which self-organization formation can occur, for example, 500 ° C., as shown in FIG. 4C, the growth rate is set to 0.2 atomic layer / second, for example. InAs quantum dots 14 are formed by supplying 2.0 atomic layers. At this time, in the process of supplying InAs, compressive strain applied to InAs increases by supplying a certain amount, InAs grows three-dimensionally, and InAs quantum dots 14 are self-organized and formed. The aggregate of dots 14 becomes a quantum dot layer.

次いで、図４（ｄ）に示すように、例えば、Ａｌ組成比が０．２で厚さが３０ｎｍのｉ型Ａｌ０.２Ｇａ０.８Ａｓ中間層１５を成長させる。 Next, as shown in FIG. 4D, for example, an i-type Al 0.2 Ga 0.8 As intermediate layer 15 having an Al composition ratio of 0.2 and a thickness of 30 nm is grown.

次いで、図５（ｅ）に示すように、ＩｎＡｓ量子ドット１４の形成工程及びｉ型Ａｌ０.２Ｇａ０.８Ａｓ中間層１５の形成工程を交互に、例えば、８回繰り返す。その結果、９層の量子ドット層を有する量子ドット積層構造１６が形成される。 Next, as shown in FIG. 5E, the process of forming InAs quantum dots 14 and the process of forming the i-type Al 0.2 Ga 0.8 As intermediate layer 15 are repeated alternately, for example, 8 times. As a result, a quantum dot stacked structure 16 having nine quantum dot layers is formed.

引き続いて、図５（ｆ）に示すように、基板温度を５００℃から６００℃に昇温しながら、量子ドット積層構造１６上に厚さが、例えば、１４０ｎｍで、Ａｌ組成比が０．２のｉ型Ａｌ０.２Ｇａ０.８Ａｓスペーサ層１７を成長させる。 Subsequently, as shown in FIG. 5 (f), while the substrate temperature is raised from 500 ° C. to 600 ° C., the thickness on the quantum dot stacked structure 16 is, for example, 140 nm and the Al composition ratio is 0.2. The i-type Al 0.2 Ga 0.8 As spacer layer 17 is grown.

引き続いて、図６（ｇ）に示すように、基板温度を６００℃に保った状態で、上部電極形成層となる厚さが、例えば、１μｍで、２×１０18ｃｍ-3のＳｉドープのｎ型ＧａＡｓ層１８を形成する。 Subsequently, as shown in FIG. 6G, with the substrate temperature maintained at 600 ° C., the thickness of the upper electrode formation layer is 1 μm, for example, and 2 × 10 18 cm −3 of Si-doped An n-type GaAs layer 18 is formed.

次いで、図６（ｈ）に示すように、標準的なリソグラフィー工程及びドライエッチング工程により、素子部を所定のサイズになるよう掘り下げ、下部電極形成層となるｎ型ＧａＡｓ層１２を露出させる。   Next, as shown in FIG. 6H, the element part is dug down to a predetermined size by a standard lithography process and a dry etching process to expose the n-type GaAs layer 12 serving as a lower electrode formation layer.

次いで、標準的な金属蒸着法により、ｎ型ＧａＡｓ層１２の露出部及びｎ型ＧａＡｓ層１８の表面に、ＡｕＧｅ層及びＡｕ層を順次蒸着してＡｕＧｅ／Ａｕ構造の陰極１９及び陽極２０を形成することによって、量子ドット型赤外線検知素子の基本構造が完成する。   Next, an AuGe layer and an Au layer are sequentially deposited on the exposed portion of the n-type GaAs layer 12 and the surface of the n-type GaAs layer 18 by a standard metal vapor deposition method to form a cathode 19 and an anode 20 having an AuGe / Au structure. By doing so, the basic structure of the quantum dot infrared detection element is completed.

この陰極１９及び陽極２０をＣＭＯＳ回路などに接続し、ｎ型ＧａＡｓ層１２とｎ型ＧａＡｓ層１８との間に電位差を与えてその間に流れる電流を検知器２１で計測することで、赤外線入射に対する量子ドットの応答として流れる光電流を観測することができる。なお、図６（ｈ）における電源２２はＣＭＯＳ回路などによる等価的な電源を示している。   The cathode 19 and the anode 20 are connected to a CMOS circuit or the like, a potential difference is applied between the n-type GaAs layer 12 and the n-type GaAs layer 18, and the current flowing between them is measured by the detector 21. The photocurrent flowing as a response of the quantum dot can be observed. Note that the power source 22 in FIG. 6H is an equivalent power source such as a CMOS circuit.

本発明の実施例１においては、厚さが３０ｎｍの中間層を有する量子ドット積層構造１６の上下にｉ型Ａｌ０.２Ｇａ０.８Ａｓスペーサ層１３，１７を形成し、量子ドット積層構造１６の厚さ（２７０ｎｍ）に対するｉ型Ａｌ０.２Ｇａ０.８Ａｓスペーサ層１３，１７の厚さの比を約０．５（１４０／２７０）にしているので、同じ量子ドット層の層数のＱＤＩＰに比較してより高い光電流を得ることができる。 In Example 1 of the present invention, i-type Al 0.2 Ga 0.8 As spacer layers 13 and 17 are formed above and below a quantum dot stacked structure 16 having an intermediate layer with a thickness of 30 nm, and a quantum dot stacked structure is formed. Since the ratio of the thickness of the i-type Al 0.2 Ga 0.8 As spacer layers 13 and 17 to the thickness of 16 (270 nm) is about 0.5 (140/270), the layers of the same quantum dot layer Higher photocurrent can be obtained compared to several QDIPs.

次に、図７を参照して、本発明の実施例２の量子ドット型赤外線撮像装置を説明するが、基本的な製造工程は、上記の実施例１と全く同様であるので製造工程の図示は省略する。図７は、本発明の実施例２の量子ドット型赤外線撮像装置の概念的斜視図である。量子ドット型赤外線検知器３１が、半絶縁性ＧａＡｓ基板側がアップサイドになるようにして、バンプ３３を介して信号処理回路を備えたＳｉ集積回路装置３２上にフリップチップボンディングされている。   Next, the quantum dot infrared imaging device according to the second embodiment of the present invention will be described with reference to FIG. 7, but the basic manufacturing process is exactly the same as the first embodiment, and the manufacturing process is illustrated. Is omitted. FIG. 7 is a conceptual perspective view of a quantum dot infrared imaging device according to Embodiment 2 of the present invention. A quantum dot infrared detector 31 is flip-chip bonded onto a Si integrated circuit device 32 having a signal processing circuit through bumps 33 with the semi-insulating GaAs substrate side facing up.

この場合の量子ドット型赤外線検知器３１は、実施例１における図６（ｈ）の工程において、二次元マトリクスアレイ状に素子を分離し、陰極側のｎ型ＧａＡｓ層１２に共通電極を形成するとともに、陽極側のｎ型ＧａＡｓ層１８に個別電極を設けたものである。   In this case, the quantum dot infrared detector 31 separates the elements in a two-dimensional matrix array in the step of FIG. 6H in the first embodiment, and forms a common electrode on the n-type GaAs layer 12 on the cathode side. In addition, an individual electrode is provided on the n-type GaAs layer 18 on the anode side.

また、バンプ３３は陽極側のｎ型ＧａＡｓ層１８に設けた個別電極に接続するように設けられている。なお、この場合の画素数は任意であるが、例えば、数百×数百以上の画素数とする。   The bumps 33 are provided so as to be connected to individual electrodes provided on the n-type GaAs layer 18 on the anode side. In this case, the number of pixels is arbitrary, but for example, the number of pixels is several hundreds × several hundreds or more.

このように、本発明の実施例２においては、量子ドット積層構造の上下にスペーサ層を形成しているので、高い光電流を得ることが可能になり、赤外線撮像装置の高感度化が可能になる。   Thus, in Example 2 of the present invention, since the spacer layers are formed above and below the quantum dot stacked structure, it is possible to obtain a high photocurrent and to increase the sensitivity of the infrared imaging device. Become.

以上、本発明の各実施例を説明してきたが、本発明は、各実施例に示した条件に限られるものではない。例えば、成長方法として分子線エピタキシャル法を用いているが、分子線エピタキシャル法に限られるものではなく、例えば、ＭＯＣＶＤ法（有機金属気相成長法）を用いても良い。   The embodiments of the present invention have been described above, but the present invention is not limited to the conditions shown in the embodiments. For example, although the molecular beam epitaxial method is used as the growth method, the method is not limited to the molecular beam epitaxial method, and for example, an MOCVD method (metal organic chemical vapor deposition method) may be used.

また、上記の実施例においては、中間層とスペーサ層とを同じ組成比のＡｌＧａＡｓで形成しているが、組成比は必ずしも同じである必要はなく、例えば、スペーサ層のＡｌ組成比を中間層のＡｌ組成比より低くしても良い。この場合、電極形成層に存在する電子から見たスペーサ層による電位障壁は低くなる。   In the above embodiment, the intermediate layer and the spacer layer are formed of AlGaAs having the same composition ratio. However, the composition ratio is not necessarily the same. For example, the Al composition ratio of the spacer layer is set to the intermediate layer. The Al composition ratio may be lower. In this case, the potential barrier due to the spacer layer as seen from the electrons present in the electrode formation layer is lowered.

１ 量子ドット積層構造
２ 量子ドット
３ 中間層
４，５ スペーサ層
６，７ 電極形成層
１１ 半絶縁性ＧａＡｓ基板
１２ ｎ型ＧａＡｓ層
１３ ｉ型Ａｌ０.２Ｇａ０.８Ａｓスペーサ層
１４ ＩｎＡｓ量子ドット
１５ ｉ型Ａｌ０.２Ｇａ０.８Ａｓ中間層
１６ 量子ドット積層構造
１７ ｉ型Ａｌ０.２Ｇａ０.８Ａｓスペーサ層
１８ ｎ型ＧａＡｓ層
１９ 陰極
２０ 陽極
２１ 検知器
２２ 電源
３１ 量子ドット型赤外線検知器
３２ Ｓｉ集積回路装置
３３ バンプ
５１ 量子ドット積層構造
５２ 量子ドット
５３ 中間層
５４，５５ 電極形成層
５６ 伝導帯側量子準位
５７，５８，５９，６１ 電子
６０ 赤外線 DESCRIPTION OF SYMBOLS 1 Quantum dot laminated structure 2 Quantum dot 3 Intermediate layer 4, 5 Spacer layer 6, 7 Electrode formation layer 11 Semi-insulating GaAs substrate 12 n-type GaAs layer 13 i-type Al 0.2 Ga 0.8 As spacer layer 14 InAs quantum Dot 15 i-type Al 0.2 Ga 0.8 As intermediate layer 16 quantum dot layered structure 17 i-type Al 0.2 Ga 0.8 As spacer layer 18 n-type GaAs layer 19 cathode 20 anode 21 detector 22 power supply 31 quantum Dot type infrared detector 32 Si integrated circuit device 33 Bump 51 Quantum dot laminated structure 52 Quantum dot 53 Intermediate layer 54, 55 Electrode forming layer 56 Conduction band side quantum levels 57, 58, 59, 61 Electron 60 Infrared

Claims (5)

複数の量子ドットからなる量子ドット層と前記量子ドット層を挟み込むとともに前記量子ドットよりバンドギャップが広い中間層からなる積層構造を複数積層した量子ドット積層構造と、前記量子ドット積層構造を挟み込む上下のスペーサ層と、前記上下のスペーサ層の外側に設ける上下の電極形成層とを有する量子ドット型赤外線検知素子。   A quantum dot stacked structure in which a plurality of stacked structures including a quantum dot layer composed of a plurality of quantum dots and the quantum dot layer and an intermediate layer having a wider band gap than the quantum dots are stacked, and upper and lower layers sandwiching the quantum dot stacked structure A quantum dot infrared detecting element having a spacer layer and upper and lower electrode forming layers provided outside the upper and lower spacer layers. 前記スペーサ層が、前記中間層と同じ材料からなる層である請求項１に記載の量子ドット型赤外線検知素子。   The quantum dot infrared detection element according to claim 1, wherein the spacer layer is a layer made of the same material as the intermediate layer. 前記上下の各スペーサ層の厚さの前記量子ドット積層構造の厚さに対する比が、０．５〜１．４であり、且つ、前記中間層の厚さが３０ｎｍ以上である請求項１または請求項２に記載の量子ドット型赤外線検知素子。   The ratio of the thickness of each of the upper and lower spacer layers to the thickness of the quantum dot stacked structure is 0.5 to 1.4, and the thickness of the intermediate layer is 30 nm or more. Item 3. The quantum dot infrared detection element according to Item 2. 前記量子ドットがＩｎ１−ｘＧａｘＡｓ（０≦ｘ＜１）からなり、前記中間層がＡｌｙＧａ１−ｙＡｓ（０≦ｙ≦１）からなり、且つ、前記スペーサ層がＡｌ１−ｚＧａ１−ｚＡｓ（０≦ｚ≦１）からなる請求項１乃至請求項３のいずれか１項に記載の量子ドット型赤外線検知素子。 The quantum dots are made of In 1-x Ga x As (0 ≦ x <1), the intermediate layer is made of Al y Ga 1-y As (0 ≦ y ≦ 1), and the spacer layer is made of Al 1. The quantum dot infrared detection element according to any one of claims 1 to 3, wherein the quantum dot infrared detection element is made of -zGa1 - zAs (0≤z≤1). 複数の量子ドットからなる量子ドット層と前記量子ドット層を挟み込むとともに前記量子ドットよりバンドギャップが広い中間層からなる積層構造を複数積層した量子ドット積層構造と、前記量子ドット積層構造を挟み込む上下のスペーサ層と、前記上下のスペーサ層の外側に設ける上下の電極形成層とを有する量子ドット型赤外線検知素子をマトリクス状に形成するとともに、前記各量子ドット型赤外線検知素子の陽極側の電極形成層に突起状電極を設けた量子ドット型赤外線検知器と、前記各突起状電極に対応する位置に接続パッドを有するとともに、信号処理回路を備えた半導体集積回路装置とを有する量子ドット型赤外線撮像装置。
A quantum dot stacked structure in which a plurality of stacked structures including a quantum dot layer composed of a plurality of quantum dots and the quantum dot layer and an intermediate layer having a wider band gap than the quantum dots are stacked, and upper and lower layers sandwiching the quantum dot stacked structure A quantum dot infrared detecting element having a spacer layer and upper and lower electrode forming layers provided outside the upper and lower spacer layers is formed in a matrix, and an electrode forming layer on the anode side of each quantum dot infrared detecting element Quantum dot infrared imaging device having a quantum dot infrared detector provided with a protruding electrode and a semiconductor integrated circuit device having a connection pad at a position corresponding to each protruding electrode and having a signal processing circuit .
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014038211A1 (en) * 2012-09-10 2014-03-13 国立大学法人神戸大学 Semiconductor device and semiconductor device producing method
JPWO2017183556A1 (en) * 2016-04-20 2019-02-21 日本精機株式会社 Head-up display device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10236400B2 (en) 2016-02-01 2019-03-19 Heptagon Micro Optics Pte. Ltd. Quantum dot film based demodulation structures

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001156298A (en) * 1999-11-26 2001-06-08 Sony Corp Semiconductor device
JP2008198677A (en) * 2007-02-09 2008-08-28 Fujitsu Ltd Manufacturing method of semiconductor device
JP2009065142A (en) * 2008-08-08 2009-03-26 Technical Research & Development Institute Ministry Of Defence Quantum dot type infrared ray detector
JP2009152246A (en) * 2007-12-18 2009-07-09 Fujitsu Ltd Quantum dot type infrared detector
JP2009231364A (en) * 2008-03-19 2009-10-08 Fujitsu Ltd Optical semiconductor device and infrared detector

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001156298A (en) * 1999-11-26 2001-06-08 Sony Corp Semiconductor device
JP2008198677A (en) * 2007-02-09 2008-08-28 Fujitsu Ltd Manufacturing method of semiconductor device
JP2009152246A (en) * 2007-12-18 2009-07-09 Fujitsu Ltd Quantum dot type infrared detector
JP2009231364A (en) * 2008-03-19 2009-10-08 Fujitsu Ltd Optical semiconductor device and infrared detector
JP2009065142A (en) * 2008-08-08 2009-03-26 Technical Research & Development Institute Ministry Of Defence Quantum dot type infrared ray detector

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014038211A1 (en) * 2012-09-10 2014-03-13 国立大学法人神戸大学 Semiconductor device and semiconductor device producing method
JPWO2014038211A1 (en) * 2012-09-10 2016-08-08 国立大学法人神戸大学 Semiconductor device and manufacturing method of semiconductor device
JPWO2017183556A1 (en) * 2016-04-20 2019-02-21 日本精機株式会社 Head-up display device

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