JP4401843B2 - Hole injection electrode and semiconductor device - Google Patents

Description

  The present invention relates to a hole injection electrode and a semiconductor device for use on a compound semiconductor crystal.

  ZnSe compound semiconductors have a large band gap of about 2.7 eV, and are promising as optoelectronic materials such as blue LDs and LEDs. However, since the top of the valence band of ZnSe is deep from the vacuum level, there is a problem that it is difficult to obtain a practical hole injection electrode that sufficiently exhibits the characteristics of the ZnSe compound semiconductor. Traditionally, to overcome this problem,

  (1) A material having a high work function (for example, Au, Pt, etc.) is used as a material for the hole injection electrode (Patent Document 1).

  (2) forming a highly doped thin film layer at the interface between the ZnSe compound semiconductor and the hole injection electrode (Non-Patent Document 1);

(3) The Schottky barrier is reduced by an alloying reaction between the ZnSe compound semiconductor and the material of the hole injection electrode (Non-Patent Document 2).
Such a method is adopted.
JP-A-6-104421 J. et al. Crystal Growth 214/215, 1064 (2000) Solid-State Electronics, vol. 42, no. 1, pp. 139-144 (1998)

  (1) is a technique generally used for a wide range of semiconductor materials in the past, and a film of a metal (Au, Pt, etc.) having a large work function is formed on a semiconductor by vacuum deposition or sputtering. Is. However, since the valence band top energy of p-type ZnSe is particularly deep as compared with a normal semiconductor such as GaAs or Si, there is no metal having a sufficiently large work function with respect to ZnSe. For this reason, when the method (1) is used, a threshold voltage that cannot be ignored is generated, and as a result, the operating voltage becomes high, which may cause a problem in practice. Further, Au and Pt have poor adhesion to ZnSe, and the electrode may be easily peeled off in a subsequent process such as wire bonding. For this reason, a semiconductor element using Au or Pt as an electrode material may not have the required reliability.

  (2) is also a method that has been used for conventional semiconductor materials in general, and is disclosed in Non-Patent Document 1, for example. This is a method of inserting a layer having a high carrier concentration between a semiconductor and a hole injection electrode.

  The semiconductor element of Non-Patent Document 1 includes a p-ZnTe layer as a layer having a high carrier concentration between p-ZnSe as a semiconductor and Au as a hole injection electrode, and p-ZnTe / p-ZnSe. It has a structure in which an MQW (multi-quantum well) structure layer is inserted. This structure eliminates the energy discontinuity between the semiconductor and the hole injection electrode, thereby reducing the Schottky barrier and realizing smooth carrier (hole) injection from the Au electrode to p-ZnSe. ing.

  Here, ZnTe or HgSe is used as the layer having a high carrier concentration, which is a material that can be easily reduced in p-type and can be reduced in resistance, and is ohmic with a metal electrode such as Au or Pt. This is because contact is obtained.

  However, in this case, ZnTe and HgSe have a lattice constant mismatch of about 7 to 8% with ZnSe, so that defects occur when ZnTe or HgSe crystals are grown on ZnSe, and further, during operation In some cases, defects may further grow due to heat generation. Non-Patent Document 1 describes that when an LED (light emitting diode) using the same is operated at 20 ° C. and a current value of 20 mA, the light emission intensity decreases to about 50% of the initial intensity after driving for 800 hours. . However, since it is considered that the lifetime of the semiconductor element is required to be 5000 hours to 10,000 hours or more, it may occur that the generation of defects must be suppressed.

  In the method (3), a metal material that can be alloyed with a compound semiconductor is formed on the compound semiconductor, and this is heat-treated for a short time, thereby forming an electrode made of an alloy layer at the interface of the p-type compound semiconductor / metal material. To form. For example, according to Non-Patent Document 2, if a Pd metal film is formed on a p-type ZnSe semiconductor by sputtering and then annealed at 250 ° C. for 2 minutes, the contact resistance between the semiconductor and the metal becomes small. It has been reported that the threshold voltage can be reduced.

  However, it is difficult to apply in manufacturing because it is possible to rapidly change the temperature of the semiconductor substrate in such a short time and to control the temperature of the entire semiconductor substrate uniformly and precisely. In addition, it is necessary to finely adjust the heating conditions according to the shapes of individual substrates having different thicknesses and sizes. For this reason, the semiconductor substrate heat treatment apparatus is required to have high performance and high-accuracy temperature control technology for satisfying these requirements, and the setting of annealing treatment conditions becomes complicated.

Furthermore, there is also a problem that various alloy phases are generated at the interface between the compound semiconductor and the metal material. For example, Non-Patent Document 2 describes that a plurality of phases such as Pd ₅ ZnSe, Pd ₆ Zn ₃₂ Se ₆ and Pd ₁₇ Se ₁₅ are formed at the interface between Pd and ZnSe depending on the annealing time. It is suggested that the Pd ₆ Zn ₃₂ Se ₆ phase and the Pd ₁₇ Se ₁₅ phase have good characteristics as an electrode layer.

  However, in an electrode layer in which a plurality of phases are generated, the performance will vary unless the formation of various reaction phases is strictly controlled. It is very difficult to control the thickness of these various reaction phases or to form only one kind of phase, and there is no variation in electrode layer performance caused by the presence of such various reaction phases. This is problematic because it tends to hinder precise control of the electrical characteristics of the semiconductor element.

  The present invention has been made under such a technical background, and an object thereof is to provide a hole injection electrode having high adhesion to a semiconductor and excellent long-term stability. Another object of the present invention is to provide a hole injection electrode that is chemically stable and has high controllability of electrical characteristics. Furthermore, it aims at providing the semiconductor element provided with the hole injection electrode which has these characteristics.

In the first aspect of the present invention, the composition formula (Pd _x Pt _y Ni _z ) _u ZnSe (u is a real number of 4 ≦ u ≦ 6, and x, y, and z are x + y + z = 1, 1> x ≧ 0, 1> y ≧ 0, 1> z ≧ 0, a hole injection electrode having an electrode layer made of a material represented by the following formula. That is, it is a hole injection electrode made of a material containing at least Pt or Ni.

  According to the first aspect of the present invention, it is possible to provide a hole injection electrode having high adhesion to a semiconductor, long life, and excellent long-term stability.

The material of the hole injection electrode of the present invention, (Pd _x Pt _y Ni _z ) _u ZnSe, has the same crystal structure as Pd ₅ TlAs. The crystal structure of the Pd ₅ TlAs type is, for example, Z. Metallkde. BD. 61 (1970) H.R. 8 p. 579, and this crystal has a space group represented by P4 / mmm. This Pd ₅ TlAs type crystal structure has a small lattice mismatch with the ZnSe-based semiconductor layer and is effective in forming a low-defect hole injection electrode. In addition, it is known that Pd ₅ ZnSe, which is one of the types in which the formation of multiphases is confirmed in Non-Patent Document 2, has this Pd ₅ TlAs type crystal structure.

In Non-Patent Document 2, the Pd ₅ ZnSe alloy phase does not mention the characteristics as a material of a Pd ₅ ZnSe single-phase hole injection electrode, but the present inventors have disclosed Pd ₅ Focusing on the fact that the crystal structure of the ZnSe phase can be formed to have an epitaxial relationship with the ZnSe crystal, an attempt was made to use the Pd ₅ ZnSe phase as a material for the hole injection electrode.

  The “epitaxial relationship” in the present invention includes a crystal axis relationship between single crystals that are usually used, but a crystal of a single crystallite and a crystallite on the polycrystal. It shall include the axial relationship. That is, in a polycrystal where the upper and lower crystals are polycrystals, a single crystallite in the lower crystal and a single crystallite in the upper crystal above the crystallite have an epitaxial relationship. And having this relationship over substantially the entire polycrystal has an epitaxial relationship.

However, it was found that when Pd ₅ ZnSe was used as the material for the hole injection electrode, the characteristics deteriorated with time, and the lifetime for practical use might become insufficient. As a cause of this, the inventors estimated that there was a problem in the properties peculiar to Pd element. That is, as a first cause, Pd is known as a metal that exothermically absorbs hydrogen. For example, defects are generated in the crystal due to heat generated when hydrogen present in the air is absorbed, or the growth of defects. It was thought that this was caused. As a second cause, hydrogen is generated at the interface between the Pd ₅ ZnSe electrode and the p-type ZnSe due to the diffusion of absorbed hydrogen, thereby creating a surface state at the ZnSe termination, and detrimental to the acceptor. I thought it was because

  Therefore, the present inventors tried to contain Pt and Ni in place of Pd. As a result, epitaxial growth can be achieved without causing lattice mismatch, and the Pd content can be reduced. Thus, it was found that the lifetime can be extended.

In the present invention, x, y and z have a relationship of x + y + z = 1, and it is considered that Pd, Pt and Ni all occupy the Pd site of the Pd ₅ TlAs structure. If the range of x, y, z, u is 4 ≦ u ≦ 6, x + y + z = 1, 1> x ≧ 0, 1> y ≧ 0, 1> z ≧ 0, a Pd ₅ TlAs type crystal structure is formed. It is possible and there is almost no change in the lattice constant. When u is less than 4 or more than 6, the Pd ₅ TlAs structure becomes unstable and another phase precipitates, resulting in defects or performance variations due to the presence of multiple phases. Therefore, an effective hole injection electrode cannot be obtained.

Note that the value x may be a value at which (Pd _x Pt _y Ni _z ) _u ZnSe has a composition in a solid solution region. The value x may be a range where Pt or Ni does not become another phase. The value x may be 0.5 or more, more preferably 0.7 or more, and even more preferably 0.8 or more, for example. In this case, the composition of the electrode layer can be kept stable. The value x may be, for example, 0.5 to 0.95, more preferably 0.8 to 0.9.

  In Non-Patent Document 2, Pd is formed in advance on ZnSe, and then various Pd—Zn—Se alloy phases are formed by heat treatment. However, the present invention needs to go through troublesome processes such as heat treatment. However, it can be formed by forming a film by a method such as a molecular beam epitaxial growth method (MBE method), a vacuum deposition method, a CVD method, or a sputtering method.

In addition, the hole injection electrode of the present invention does not need to be entirely formed of the above composition formula (Pd _x Pt _y Ni _z ) _u ZnSe, and has an electrode layer formed by this composition formula. It should be. The electrode layer formed by this composition formula is formed in contact with the semiconductor layer, in order to form a hole injection electrode having high adhesion to the semiconductor, long life, and excellent long-term stability. It is particularly effective.

A second aspect of the present invention, the composition formula _{(Zn 1-α-β Mg} α Cd β) (Se 1-m-n S m Te n) ( where the mole ratio m, n and alpha, beta is m + n ≦ 1, 0 ≦ m ≦ 1, 0 ≦ n ≦ 0.2, 0 ≦ α ≦ 0.2, 0 ≦ β ≦ 0.2), and the hole injection electrode of aspect 1 And a hole injection electrode formed so that the electrode layer is in contact with the semiconductor layer (mode 2).

  Conventionally, since the top of the ZnSe valence band is deep from the vacuum level, it has been difficult to obtain a hole injection electrode that sufficiently exhibits the characteristics of a ZnSe-based compound semiconductor. If the electrode is used, the characteristics of the compound semiconductor can be sufficiently exhibited.

Further, as described above, since the hole injection electrode of the present invention has a Pd ₅ TlAs type crystal structure, it has good lattice constant matching with the compound semiconductor. In the case of ZnS _0.3 Se _0.7 (that is, α = 0, β = 0, m = 0.3, n = 0), the lattice constant matching with the hole injection electrode of the present invention is the best. Therefore, it is preferable because the adhesion is improved and the life is extended. Note that if the electrode layer and the semiconductor layer are in contact with each other, lattice matching can be obtained, so that the effects of the present invention can be obtained regardless of the vertical relationship between the electrode layer and the semiconductor layer.

  The ZnSe-based semiconductor of aspect 2 is a direct transition type wide gap semiconductor having a zinc blende type crystal structure, and is suitable as a semiconductor material for a light emitting diode or a laser diode. Depending on the purpose of adjusting the forbidden band width, a part of the Zn site may be replaced with Mg or Cd, and a part of the Se site may be replaced with S or Te. However, if the molar ratios α and β of Mg and Cd exceed 0.2, the crystal is no longer a zinc blende structure, which is not suitable. On the other hand, when the molar ratio n of Te exceeds 0.2, absorption in the visible region occurs and the emitted light is absorbed, which is not suitable.

  In the semiconductor element according to aspect 2 of the present invention, the semiconductor layer is made of a single crystal with [001] axis orientation, and the [001] axis of the electrode layer is substantially parallel to the [001] axis of the semiconductor layer. Preferable (Aspect 3) Further, it is preferable that the semiconductor layer is a zinc-blende-type single crystal with [001] axis orientation and the electrode layer is a heteroepitaxial growth layer with [001] axis orientation.

The hole injection electrode of the present invention can be epitaxially grown on the (001) plane of the ZnSe-based semiconductor layer according to Aspect 2. That is, on the (001) plane of the ZnSe-based semiconductor _{layer, (Pd x Pt y Ni z} ) when growing the u ZnSe, as shown in FIG _{26,27, ZnSe [001] // (} Pd x Pt y Ni _{z) u} ZnSe _[001], the axis of the _{ZnSe [110] // (Pd x} Pt y Ni z) u ZnSe [100], ZnSe [-110] // (Pd x Pt y Ni z) u ZnSe [010] You can grow with a relationship. For example, when the ZnSe-based semiconductor is ZnSe, ZnSe has a zinc blende type crystal structure, is cubic, has a lattice constant of 5.7 [Å], and has a ZnSe (110) plane spacing of 4.0 [Å. ]. The interplanar spacing of (Pd _x Pt _y Ni _z ) _u ZnSe (100) is about 4.0 [Å]. That is, the lattice mismatch that occurs in (Pd _x Pt _y Ni _z ) _u ZnSe and ZnSe is about 1%. Further, for example, ZnSe-based _ZnS 0.3 _{Se 0.7} For (α = 0, β = 0 , m = 0.3, n = 0), the most and _{(Pd x Pt y Ni z)} u ZnSe electrode There is lattice constant matching, and the lattice mismatch is about 0%. These values are much smaller than the lattice mismatch of 7-8% where ZnTe or HgSe is between ZnSe. For this reason, it is difficult for defects to occur at the interface between (Pd _x Pt _y Ni _z ) _u ZnSe and ZnSe, and the adhesion between both layers is high. Furthermore, when a current is passed through the interface, defects are difficult to grow and the semiconductor has a long lifetime, which is preferable.

Further, when an epitaxial relationship is formed between the electrode layer in the hole injection electrode of the present invention and the ZnSe-based semiconductor layer via the (001) planes of both layers, an annealing process as in the conventional method is not required. It is. For this reason, the high performance of a heat processing apparatus and the advanced control technique become unnecessary, and it can manufacture easily in a short time. In addition, since it is relatively easy to form the (Pd _x Pty _y N _z ) _u ZnSe phase with good controllability, a plurality of undesired crystal phases are not duplicated, resulting in variations in electrode layer performance. In addition, the electrical characteristics can be precisely controlled. In the above epitaxial relationship, for example, the electrode layer may be formed by epitaxial growth on the semiconductor layer, or the semiconductor layer may be formed by epitaxial growth on the electrode layer.

  In the semiconductor element of aspect 2 of the present invention, the semiconductor layer is made of a polycrystal having [001] axis preferential orientation, and the [001] axis of the electrode layer is substantially parallel to the [001] axis of the semiconductor layer. It is preferable (Aspect 4).

  Conventionally, a p-type semiconductor layer made of a single crystal has been used for a semiconductor element. This is because the polyconductivity cannot provide the electrical conductivity required for the p-type semiconductor layer. In addition, in order to make the p-type semiconductor layer a single crystal, it is necessary to use a single crystal substrate as a substrate.

However, the present invention can also use a p-type semiconductor layer made of polycrystal. That is, the p-type ZnSe-based semiconductor layer may be a polycrystal. The hole injection electrode of the present invention can also be grown on a polycrystalline p-type ZnSe-based semiconductor layer. In particular, when Cu is doped in the p-type ZnSe-based semiconductor layer, the hole concentration can be increased, which is preferable as a polycrystalline p-type semiconductor layer. Cu-doped p-type ZnSe is sufficiently conductive even if it is polycrystalline, and when (Pd _x Pt _y Ni _z ) _u ZnSe is joined, there is no threshold voltage and it is joined ohmicly.

  As described above, since a polycrystalline body can be used as the p-type semiconductor layer, it is not necessary to use a single crystal substrate as a substrate, and the selectivity of a substrate such as a polycrystalline substrate or a glass substrate can be expanded. Moreover, it is preferable also in terms of production efficiency and cost. Of the semiconductor layer and the electrode layer, any substrate can be used as long as the lower layer can be formed with the [001] axis orientation. Thus, the semiconductor layer and the electrode layer are epitaxially formed via the (001) planes of both layers. A relationship can be formed.

  When a polycrystalline substrate is used as the substrate, it is preferable to use a substrate with [001] axis preferential orientation and form a semiconductor layer or an electrode layer on the (001) plane of this substrate. This is because the configuration of aspect 4 can be easily obtained.

  Moreover, in the semiconductor element of Aspect 4 of the present invention, the semiconductor layer and the electrode layer may be formed on a glass substrate (Aspect 5).

  In the semiconductor element according to any one of aspects 2 to 5 of the present invention, the thickness of the electrode layer is preferably 10 nm or more and 10 μm or less (Aspect 6).

  The thickness of the electrode layer in the hole injection electrode of the present invention is preferably 10 nm or more and 10 μm or less. If it is 10 μm or more, the adhesion to the semiconductor layer is lowered and it is easy to peel off, and if it is 10 nm or less, the performance (lifetime, operational stability) as an electrode is hindered. The thickness of the electrode layer is more preferably 20 nm or more and 1 μm or less because the adhesion with the semiconductor layer is good and the performance (life and operational stability) as an electrode is good.

In the semiconductor element according to any one of aspects 2 to 6 of the present invention, the semiconductor layer preferably has a hole concentration of 1 × 10 ¹⁸ cm ⁻³ or more and 1 × 10 ²² cm ⁻³ or less (aspect 7). . In the semiconductor element according to any one of aspects 2 to 7 of the present invention, it is more preferable that the semiconductor layer is a p-type semiconductor layer containing a Cu dopant (aspect 8).

The hole injection electrode of the present invention is particularly effective when used for bonding holes to a p-type ZnSe semiconductor and injecting holes into the semiconductor among ZnSe semiconductors. A p-type ZnSe semiconductor is an example of a semiconductor layer. The p-type ZnSe semiconductor may be a ZnSe-based semiconductor given p-type characteristics with a dopant. Here, Li or N is known as a dopant that imparts p-type polarity to a ZnSe-based semiconductor. When Li is used, the hole concentration in the ZnSe-based semiconductor can be increased to about 1 × 10 ¹⁷ cm ⁻³ . On the other hand, when N is used, the hole concentration can be increased to about 1 × 10 ¹⁸ cm ⁻³ . The ZnSe-based semiconductor gave p-type characteristics by these dopants, by joining _{(Pd x Pt y Ni z)} u ZnSe electrode of the present invention can inject holes into the semiconductor.

When the hole concentration (hole carrier density) in the ZnSe-based semiconductor is further increased, for example, when several mol% of Cu is given as a dopant, (Pd _x Pt _y Ni _z ) _u ZnSe is p It is ohmicly bonded to a type ZnSe-based semiconductor. A higher hole concentration is preferable because ohmic contact is achieved and efficiency increases. When Cu is used as the dopant, it is preferable because high-concentration holes (for example, 1 × 10 ¹⁶ to 1 × 10 ²³ cm ⁻³ ) can be injected.

In addition, the hole concentration of the Cu-doped ZnSe semiconductor which has been conventionally studied is at most 10 ¹⁴ cm ⁻³ , which is much lower than the additive concentration of the present application. This is because Cu has conventionally been known to form a deep acceptor level, so it is difficult to reduce the resistance, and when the Cu doping amount is increased further, the luminous efficiency is remarkably deteriorated. This is due to the fact that it was not interested as an optoelectronic material due to the fact that it was known.

  Under such circumstances, in the present invention, a high Cu doping amount that has not been studied in the past has been studied for the first time. As a result of the investigation, a Cu doped ZnSe semiconductor having a low resistance and a high hole concentration is obtained. It is what I found.

The work function of the hole injection electrode of the present invention is in the range of 5 to 6 eV, and is close to the valence band top energy of ZnSe of 6.3 eV. For this reason, when bonded to p-type ZnSe, not only can holes be injected into the valence band of ZnSe, but also the contact resistance at the interface is low, so the efficiency is good. For example, when it is joined to N-doped p-type ZnSe, holes can be injected when a voltage of about 2 V is applied. In particular, a p-type ZnSe semiconductor having a higher hole concentration than an N-doped p-type ZnSe semiconductor, for example, a Cu-doped p-type ZnSe semiconductor (for example, 1 × 10 ¹⁶ to 1 × 10 ²³ cm ⁻³ ). When the hole injection electrode of the present invention is bonded to the substrate, ohmic junction is realized, and holes can be injected efficiently.

  Further, the semiconductor element according to any one of aspects 2 to 8 of the present invention can be a light emitting diode (LED), a diode, a laser diode, a photodiode, or a solar cell (aspect 9).

  According to the present invention, the top of the valence band, such as a ZnSe compound semiconductor, can be applied to a material deep from the vacuum level, has high controllability of electrical characteristics, good adhesion to the semiconductor, and long-term stability. Can be obtained. In addition, a semiconductor element having these characteristics can be obtained.

As a typical embodiment of the present invention, an example of a semiconductor element using a (Pd _x Pt _y Ni _z ) _u ZnSe electrode layer will be described. FIG. 1 is a cross-sectional view of a typical light emitting diode of the present invention. This light emitting diode is formed on a substrate 11 in order by an n-type electrode 12, an n-type semiconductor 13, a p-type semiconductor 14, and a p-type electrode 15. Here, the p-type electrode 15 corresponds to the hole injection electrode of the present invention, and includes an electrode layer in contact with the p-type semiconductor 14.

Specifically, on a glass substrate 11 used as a substrate, an ITO layer 12 (0.5 μm thickness) as an n-type electrode and a Cl-doped ZnS _0.3 Se _0.7 layer 13 (1 μm thickness) as an n-type semiconductor in order. ), Cu-doped ZnS _0.3 Se _0.7 layer 14 (1 μm thickness) as a p-type semiconductor, compositional formula (Pd _0.8 Pt _0.1 Ni _0.1 ) ₅ ZnSe as a p-type electrode A hole injection electrode 15 (0.1 μm thick) was laminated. The laminated (Pd _0.8 Pt _0.1 Ni _0.1 ) ₅ ZnSe is an example of an electrode layer. Here, the formed Cu-doped ZnSe semiconductor layer is a [001] axis preferentially oriented polycrystalline body, and a (Pd _0.8 Pt _0.1 Ni _0.1 ) ₅ ZnSe electrode layer formed thereon. Was formed so as to have an epitaxial relationship with respect to the [001] axis of the semiconductor layer, that is, the [001] axis of the semiconductor layer and the [001] axis of the electrode layer were formed substantially parallel to each other. The reason why the ZnSe-based compound semiconductor is used is that the effect of the present invention becomes remarkable because the band gap is as large as 2.7 eV. The reason why the glass substrate or the ITO layer is used is that it is transparent, so that the emitted light can be transmitted and easily seen.

In this semiconductor element, the positive electrode of the power source is connected to the (Pd _0.8 Pt _0.1 Ni _0.1 ) ₅ ZnSe electrode, the negative electrode of the power source is connected to the ITO layer 12, and a voltage of 3 V or more is applied between both electrodes. When a potential difference is applied, holes are injected from the (Pd _0.8 Pt _0.1 Ni _0.1 ) ₅ ZnSe electrode layer 15 into the valence band of the Cu-doped ZnS _0.3 Se _0.7 layer 14. Electrons are injected from the ITO 12 into the conduction band of the Cl-doped ZnS _0.3 Se _0.7 layer 13. Holes and electrons recombine at the interface of both ZnS _0.3 Se _0.7 layers to emit visible light, pass through the transparent ITO film 12 and the glass substrate 11, and are emitted downward in the figure to emit light. Functions as a diode.

  The hole injection electrode is a portion connected to the positive electrode of the power source in, for example, a semiconductor element. The hole injection electrode is electrically connected to, for example, a p-type semiconductor layer in a semiconductor element, and supplies holes to the p-type semiconductor layer according to electric power received from a power source. The hole injection electrode may further include a layer other than the electrode layer according to the present invention, such as a metal layer. The electrode layer may be connected to a power source through a metal layer formed of, for example, Al, Au, or Pt. The electrode layer is a predetermined layered portion included in the hole injection electrode. The electrode layer electrically connects an external power source and, for example, this semiconductor element.

  Hereinafter, the present invention will be described in more detail with reference to examples.

With reference to FIG. 2, the polycrystalline Cu doped p-type on ZnSe as a p-type semiconductor layer, an example of using the electrodes _{(Pd x Pt y Ni z)} u ZnSe.

A polycrystalline Cu-doped p-type ZnSe layer 22 having a thickness of about 1 μm was formed as a p-type semiconductor layer on the glass substrate 21 using a crucible heating type vacuum deposition method. At this time, the vapor deposition was performed with the substrate temperature maintained at 200 ° C. and the heating set temperatures of the respective Zn, Se, and Cu raw materials being 250 ° C., 150 ° C., and 1000 ° C., respectively. The partial pressure ratio of each raw material at this time was Zn: Se: Cu≈25: 80: 1, and the hole carrier concentration was about 2 × 10 ²¹ cm ⁻³ . On top of this, a (Pd _x Pt _y Ni _z ) _u ZnSe film 23 was formed to a thickness of about 300 nm as a hole injection electrode. _{(Pd x Pt y Ni z)} u ZnSe film 23 is an example of the electrode layer. Vapor deposition was performed using a crucible heating type vacuum vapor deposition method, changing the partial pressure ratios of the Pd, Pt, and Ni raw materials and changing the x, y, z, and u parameters. The substrate temperature was maintained at 200 ° C., and the heating set temperatures of the Zn and Se raw materials were 250 ° C. and 150 ° C., respectively. In this manner, electrodes were formed in a shape having a diameter of 0.5 mm and an inter-electrode spacing of 5 mm to obtain a semiconductor element.

  The obtained semiconductor element was subjected to IV measurement, and a threshold voltage in each parameter was obtained. In the measurement, each of the parameters x, y, and z was changed in increments of 0.1 in the range of 0.1 to 0.9. The points where the x, y, z, and u parameters were measured are indicated by black circles in FIG.

  As a result of the measurement, it was confirmed that the threshold voltage disappeared under any condition and the ohmic junction was satisfactorily performed. Even when the value of u is in the range of 4 to 6 other than 5, the threshold voltage showed the same tendency as when u = 5, and it was confirmed that a good ohmic junction with p-type Cu-doped ZnSe was obtained. Note that the value of u is preferably about 5 (for example, 4.8 to 5.2). In this case, a particularly good ohmic junction can be obtained.

With reference to FIG. 3, the single-crystal N-doped p-type on ZnSe as a p-type semiconductor layer, an example of using the hole injection electrode _{(Pd x Pt y Ni z)} u ZnSe.

The ZnSe single crystal substrate 31 oriented with a high resistance [001] axis was subjected to acid etching, and further subjected to thermal etching at 500 ° C. for 15 minutes in an MBE vacuum chamber having a degree of vacuum of 10 ⁻⁵ Pa or higher. The high-resistance ZnSe single crystal substrate is, for example, a ZnSe single crystal substrate that is not doped with impurities. On the (001) plane of this substrate, an N-doped p-type ZnSe layer 32 was epitaxially grown by about 1 μm by MBE. The p-type ZnSe layer 32 is an example of a semiconductor layer. The substrate temperature was 250 ° C., and the flux ratio (molecular beam partial pressure ratio) Zn: Se was approximately 1: 2. A high-frequency excitation type radical beam source was used for N doping, with a high-frequency output of 250 W and a nitrogen gas flow rate of 0.05 sccm. The carrier concentration of this p-type ZnSe was about 1 × 10 ¹⁸ cm ⁻³ . As the hole injection electrode on the _{(Pd x} Pt _y Ni _z) for approximately 300nm deposited u ZnSe layer 33. _{(Pd x Pt y Ni z)} u ZnSe layer 33 is an example of the electrode layer. Using a crucible heating type vacuum deposition method, the partial pressure ratios of the Pd, Pt, and Ni raw materials were changed, and the x, y, z, and u parameters were changed. The substrate temperature was maintained at 200 ° C., and the heating set temperatures of the Zn and Se raw materials were 250 ° C. and 150 ° C., respectively. One set was uniformly formed, and the other was formed as an electrode having a diameter of 0.5 mm and a distance between electrodes of 5 mm, and the work function of each sample formed uniformly was determined. For the work function, a photoelectron spectrometer was used. On the other hand, the threshold voltage of each sample formed as an electrode was determined by performing IV measurement.

Tables 1 to 3 show the work functions obtained for each parameter. FIG. 25 shows the threshold voltage measured at each parameter point. In FIG. 25, black circles indicate parameters with a threshold voltage of 1.1 to 1.5 V, black squares indicate parameters with a threshold voltage of 1.5 to 2.0 V, black The triangle mark indicates a parameter whose threshold voltage is 2.0 to 2.4V. _{(Pd x Pt y Ni z)} 5 ZnSe work function became range 5～6EV. When the film was formed on N-dope, the threshold voltage remained about 2V. However, the threshold voltage was lower than when the metal electrodes as shown in Table 4 were used. Even when the value of u is in the range of 4 to 6 other than 5, the work function and the threshold voltage show the same tendency results as when u = 5, and it is confirmed that the threshold voltage is smaller than when using a metal electrode. did.

Furthermore, when the value of u was less than 4 or exceeded 6, the threshold voltage increased. As an example, when x = 0.8, y = 0.2, and z = 0, the change in threshold voltage when the condition of u is changed is shown in FIG. When u is less than 4 or exceeds 6, it is considered that the threshold voltage increases because the Pd ₅ TlAs structure becomes unstable and another phase precipitates.

In FIG. 5, the thickness of the hole injection electrode (Pd _x Pt _y Ni _z ) _u ZnSe film is changed variously, and the current value (Pd _x Pty _y Ni _z ) _u when a voltage of 0.1 V is applied. The ZnSe film thickness dependency was shown. As shown in FIG. 5, when the thickness was 10 nm or less, the performance as an electrode was hindered. However, when the thickness was 10 nm or more, the current value was not greatly changed and it was good. However, if it is 10 μm or more, it tends to peel off at the time of ultrasonic wire bonding, which is not preferable.

An example of bonding using a hole injection electrode (Pd _x Pt _y Ni _z ) _u ZnSe on polycrystalline Cu-doped p-type ZnSe will be described with reference to FIGS.

A polycrystalline Cu-doped p-type ZnSe layer 62 was formed on the glass substrate 61 with a thickness of about 1 μm using a crucible heating vacuum deposition method. The polycrystalline Cu-doped p-type ZnSe layer 62 is an example of a p-type semiconductor layer containing a Cu dopant. The polycrystalline Cu-doped p-type ZnSe layer 62 is also an example of a polycrystalline body formed on a glass substrate. Vapor deposition was performed with the substrate temperature maintained at 200 ° C. and the heating set temperatures of the respective Zn, Se, and Cu raw materials being 250 ° C., 150 ° C., and 1000 ° C., respectively. The partial pressure ratio of each raw material at this time was Zn: Se: Cu≈25: 80: 1. Two types of electrodes were produced on this. One _was prepared by approximately 300nm deposited _{(Pd x Pt y Ni z)} u ZnSe layer 63. _{(Pd x Pt y Ni z)} u ZnSe layer 63 is an example of the electrode layer. This film formation is performed using a crucible heating-type vacuum deposition method, the substrate temperature is maintained at 200 ° C., the heating set temperatures of the respective Zn and Se raw materials are 250 ° C. and 150 ° C., respectively, and the diameter is 0.5 mm. It was formed as an electrode. Further, an Al film 64 having a thickness of about 50 nm was formed thereon by sputtering, and this was used as a pad. This is shown in FIG. The (Pd _x Pt _y Ni _z ) _u ZnSe layer 63 and the Al film 64 may constitute a hole injection electrode. The other electrode was formed by depositing an Au film 65 of 300 nm in a similar shape with a diameter of 0.5 mm by using a crucible heating type vacuum deposition method. This is shown in FIG. Further, an Al film 64 having a thickness of about 50 nm was formed thereon by sputtering, and this was used as a pad. Ultrasonic bonding was performed on these two types of electrodes using an Al wire having a diameter of 50 μm.

The pull test method was used for evaluating these junctions. As shown in FIG. 8, the needle at the tip of the tension gauge was hooked on the bonded wire and raised directly above. When the tension gauge was 2.5 gf, it was peeled off from the joint portion of the Al wire bonded on the Al / Au. _{However, Al / (Pd x Pt y} Ni z) Al wires were bonded onto u ZnSe was not that or broken or peeled off from the junction. Therefore, it was confirmed that the adhesiveness was higher when the electrode (Pd _x Pt _y Ni _z ) _u ZnSe was used on ZnSe.

Using a hole injection electrode _{(Pd x Pt y Ni z)} u ZnSe polycrystalline Cu doped p-type on ZnSe, was subjected to a current test. This will be described with reference to FIGS.

A polycrystalline Cu-doped p-type ZnSe layer 22 was formed on the glass substrate 21 with a thickness of about 1 μm by using a crucible heating vacuum deposition method. Polycrystalline Cu-doped p-type ZnSe is an example of a polycrystalline body formed on a p-type semiconductor layer containing a Cu dopant and a glass substrate.
Vapor deposition was performed with the substrate temperature maintained at 200 ° C. and the heating set temperatures of the respective Zn, Se, and Cu raw materials being 250 ° C., 150 ° C., and 1000 ° C., respectively. The partial pressure ratio of each raw material at this time was Zn: Se: Cu≈25: 80: 1.

Next, two types of electrodes were produced on this. One was a crucible heating type vacuum vapor deposition method, in which a (Pd _x Pt _y Ni _z ) _u ZnSe layer 23 was formed to a thickness of about 300 nm, and formed as an electrode having a diameter of 0.5 mm and an interelectrode distance of 5 mm. (FIG. 9). _{(Pd x Pt y Ni z)} u ZnSe layer 23 is an example of the electrode layer. For the other electrode, a 300 nm Au film 65 having a diameter of 0.5 mm and an interelectrode spacing of 5 mm was formed using a crucible heating vacuum deposition method (FIG. 10). As a result, an Au electrode as an example of a metal electrode was formed on the p-type semiconductor layer containing Cu dopant. In another example, the metal electrode may be formed of, for example, Pt or Al instead of Au.

The electrodes were subjected to an energization test at a constant current of 20 mA using probes and compared. As a result, the lifetime of the Au electrode was 200 hours. In addition, the (Pd _x Pt _y Ni _z ) _u ZnSe electrode operated stably for 1000 hours or more. As a result, it was confirmed that the (Pd _x Pt _y Ni _z ) _u ZnSe electrode has high reliability as an electrode.

Further, by continuing the energization test, it was confirmed that among the (Pd _x Pt _y Ni _z ) _u ZnSe electrodes, the electrode having a lower Pd content has a longer lifetime. It was shown that the lifetime was further increased by reducing the Pd content and mixing Ni and Pt.

  An example applied to a light-emitting diode manufactured over a glass substrate will be described with reference to FIG.

An ITO film 42 having a thickness of 500 nm was formed on the glass substrate 41 as an n-type electrode by sputtering. A Cl-doped n-type ZnSe layer 43 was formed thereon as an n-type semiconductor by using a crucible heating type vacuum vapor deposition method. Here, ZnCl ₂ was used as the Cl source, and the set temperature was 210 ° C. On the formed n-type ZnS _0.3 Se _0.7 film 43, a Cu-doped p-type ZnS _0.3 Se _0.7 layer 44 was formed as a p-type semiconductor. The Cu-doped p-type ZnS _0.3 Se _0.7 layer 44 is an example of a p-type semiconductor layer containing a Cu dopant. The set temperature of Cu during growth was 1000 ° C. In this series of growth, the substrate temperature was 250 ° C. The hole concentration at this time was 1 × 10 ²¹ cm ⁻³ . Subsequently, a (Pd _0.8 Pt _0.1 Ni _0.1 ) ₅ ZnSe layer 45 was laminated on the p-type ZnSe (p-type ZnS _0.3 Se _0.7 layer 44) as a hole injection electrode. The (Pd _0.8 Pt _0.1 Ni _0.1 ) ₅ ZnSe layer 45 is an example of an electrode layer. At this time, the substrate temperature was set to 200 ° C., and the mass ratio of each raw material was set to Pd: Pt: Ni: ZnSe≈4: 0.5: 0.5: 1. Further, an Al film 46 was formed thereon by sputtering to form an electrode having a diameter of 0.5 mm. On this, ultrasonic bonding was performed using an Al wire having a diameter of 50 μm. Finally, an In film 47 was formed on the ITO film 42 to form an electrode. As shown in FIG. 12, the electrical characteristics of the device showed rectification with a threshold voltage of 3V. When 5 V was applied, light was emitted and a spectrum having a peak at a wavelength of 480 nm was obtained. This is shown in FIG.

  Next, an example in which the present invention is applied to light emission by a diode will be described. A light emitting diode as shown in FIG. 14 was produced.

As the substrate, n-type ZnSe single crystal 71 oriented in the [001] axis was used. This substrate was subjected to acid etching, and further subjected to thermal etching at 500 ° C. for 15 minutes in an MBE vacuum chamber having a degree of vacuum of 10 ⁻⁵ Pa or higher. A Cl-doped n-type ZnSe layer 72 was formed as an n-type semiconductor on the substrate by MBE. Here, ZnCl ₂ was used as the Cl source, and the set temperature was 210 ° C. The carrier concentration of the obtained n-type ZnSe was about 1 × 10 ¹⁸ cm ⁻³ . On this n-type ZnSe layer, a Cu-doped p-type ZnSe layer 73 was epitaxially grown as a p-type semiconductor. The Cu-doped p-type ZnSe layer 73 is an example of a p-type semiconductor layer containing a Cu dopant. Here, the set temperature of Cu during growth was set to 1000 ° C. In this series of growth, the substrate temperature was set to 250 ° C., and the flux ratio Zn: Se was set to about 1: 2. The hole concentration of the obtained p-type ZnSe was 2 × 10 ²¹ cm ⁻³ .

Subsequently, a (Pd _0.8 Pt _0.1 Ni _0.1 ) ₅ ZnSe layer 74 was laminated on the p-type ZnSe as a hole injection electrode. The (Pd _0.8 Pt _0.1 Ni _0.1 ) ₅ ZnSe layer 74 is an example of an electrode layer. Here, an electrode layer of a hole injection electrode _{(Pd 0.8 Pt 0.1 Ni 0.1)} 5 result of X-ray diffraction analysis of the ZnSe layer, shown in FIG. 15. In addition, since the diffraction intensity of ZnSe is strong, it measured by omitting 30-35, 62-70, 109-110 [deg]. The observed diffraction was found to have the same structure as that reported for Pd _5.1 ZnSe.

  Finally, an In layer 75 was applied to the n-type substrate as an electrode to obtain electrical characteristics. As a result, the rectifying property of a forward bias threshold voltage of about 3 V at the pn junction was shown. When a voltage of 5 V was applied, light emission with a peak wavelength of 470 nm was obtained. As shown in FIG. 16, when continuous operation was performed at 20 mA, the emission intensity was attenuated to 90% of the initial intensity even after 1000 hours, and stable operation for a long time could be confirmed.

  Next, an example of a diode in which the present invention is applied to a polycrystalline substrate will be described with reference to FIG.

A high-resistance ZnSe polycrystal 101 preferentially oriented on the [001] axis was used as the substrate. This substrate was subjected to acid etching, and further subjected to thermal etching at 500 ° C. for 15 minutes in an MBE vacuum chamber having a degree of vacuum of 10 ⁻⁵ Pa or higher. A (Pd _0.9 Pt _0.1 Ni ₀ ) ₅ ZnSe layer 102 was laminated as a hole injection electrode on the (001) plane of this substrate by using the MBE method. The (Pd _0.9 Pt _0.1 Ni ₀ ) ₅ ZnSe layer 102 is an example of an electrode layer. Next, a Cu-doped p-type ZnSe layer 103 was stacked as a p-type semiconductor layer by MBE. Thereby, in this example, the p-type semiconductor layer is formed on the electrode layer while preferentially orientating in the [001] axis. The set temperature of Cu at this time was 1000 ° C. The hole concentration of the obtained p-type ZnSe was 2 × 10 ²¹ cm ⁻³ . Next, a Cl-doped n-type ZnSe layer 104 was formed as an n-type semiconductor layer. At this time, ZnCl ₂ was used as the Cl source, and the set temperature was 210 ° C. The carrier concentration of this n-type ZnSe was about 1 × 10 ¹⁸ cm ⁻³ . In this series of growth, the substrate temperature was set to 250 ° C., and the flux ratio Zn: Se was set to about 1: 2.

Further, Al films 105 and 106 were formed by sputtering on the n-type ZnSe layer 104 and the (Pd _0.9 Pt _0.1 Ni ₀ ) ₅ ZnSe layer 102 to form an electrode having a diameter of 0.5 mm. . On this, ultrasonic bonding was performed using an Al wire having a diameter of 50 μm.

  As shown in FIG. 18, the diode thus fabricated exhibited a rectifying property with a forward bias threshold voltage of about 4 V at the pn junction.

  Next, an example of a laser diode in which the present invention is applied to a single crystal substrate will be described with reference to FIG.

As the substrate, an n-type GaAs substrate 81 oriented in the [001] axis was used. This substrate was subjected to acid etching, and further subjected to thermal etching at 500 ° C. for 15 minutes in an MBE vacuum chamber having a degree of vacuum of 10 ⁻⁵ Pa or higher. On the (001) plane of this substrate, an n-type Cl-doped ZnS _0.06 Se _0.94 layer 82 having consistency with the GaAs substrate was used as a cladding layer, and a 1 μm film was formed. On top of this, a Zn _0.8 Cd _0.2 Se quantum well layer 83 was used as an active layer, and a film of 7 nm was formed. Furthermore, it was used for the p-type Cu-doped ZnS _0.06 Se _0.94 layer 84 clad layer, and was formed to 1 μm. A ZnSSe-based layer 85 is formed as a buffer layer so that the lattices of the layers stacked thereon are not distorted, and the uppermost contact layer is a Cu-doped ZnS _0.3 Se _0.7 layer 86. I made it. The Cu-doped ZnS _0.3 Se _0.7 layer 86 is an example of a p-type semiconductor layer containing a Cu dopant. Further, a (Pd _0.9 Pt _0.1 Ni ₀ ) ₅ ZnSe layer 87 was stacked thereon as an electrode, and this was used as a p-type electrode. This p-type electrode is an example of a hole injection electrode. The (Pd _0.9 Pt _0.1 Ni ₀ ) ₅ ZnSe layer 87 is an example of an electrode layer. An In layer 88 was used for the n-type electrode.

FIG. 20 shows the LI characteristics measured under a pulse drive with a pulse width of 1 μs and a repetition frequency of 1 kHz at 77K. The optical output rose at a current value of 200 mA. The threshold current density was 0.8 kA / cm ² . The emission spectrum is shown in FIG.

  An example of a photodiode in which the present invention is applied to a single crystal substrate will be described with reference to FIGS.

As the substrate, n-type ZnSe single crystal 91 oriented in the [001] axis was used. This substrate was subjected to acid etching, and further subjected to thermal etching at 500 ° C. for 15 minutes in an MBE vacuum chamber having a degree of vacuum of 10 ⁻⁵ Pa or higher. A Cl-doped n-type ZnSe layer 92 was formed on the (001) plane of this substrate by MBE. Here, ZnCl ₂ was used as the Cl source, and the set temperature was 210 ° C. The carrier concentration of this n-type ZnSe was about 1 × 10 ¹⁸ cm ⁻³ . A non-doped ZnSe film 93 was laminated on the n-type ZnSe film. Further, a Cu-doped p-type ZnSe layer 94 was epitaxially grown thereon. The Cu-doped p-type ZnSe layer 94 is an example of a p-type semiconductor layer containing a Cu dopant. The set temperature of Cu during growth was 1000 ° C. In this series of growth, the substrate temperature was set to 250 ° C., and the flux ratio Zn: Se was set to about 1: 2. The hole concentration of the obtained p-type ZnSe was 2 × 10 ²¹ cm ⁻³ .

Subsequently, a (Pd _0.9 Pt _0.1 Ni ₀ ) _5.1 ZnSe layer 95 was laminated on the p-type ZnSe layer 94. (Pd _0.9 Pt _0.1 Ni ₀ ) _{5.1 The} ZnSe layer 95 is an example of an electrode layer. Finally, an In layer 96 was attached to the n-type substrate to form an electrode.

  As a result, spectral sensitivity characteristics having a peak at about 470 nm were obtained.

  An example of a solar cell in which the present invention is applied to a glass substrate will be described with reference to FIG.

An ITO layer 202 was formed to a thickness of 500 nm on the glass substrate 201 by a sputtering method. A Cl-doped n-type ZnSe layer 203 was formed thereon using a crucible heating type vacuum deposition method. Here, ZnCl ₂ was used as the Cl source, and the set temperature was 210 ° C. A non-doped ZnSe film 204 was laminated on the n-type ZnSe layer 203. Further, a Cu-doped p-type ZnSe layer 205 was laminated thereon. The Cu-doped p-type ZnSe layer 205 is an example of a p-type semiconductor layer containing a Cu dopant. The set temperature of Cu at this time was 1000 ° C. In this series of growth, the substrate temperature was 250 ° C., and the partial pressure ratio Zn: Se was about 1: 2. Subsequently, a hole injection electrode (Pd _0.9 Pt _0.1 Ni ₀ ) ₅ ZnSe layer 206 was laminated on the p-type ZnSe layer 205. (Pd _0.9 Pt _0.1 Ni ₀ ) _5.1 ZnSe layer 206 is an example of an electrode layer. Further, an Al film 207 was formed thereon by sputtering to form an electrode having a diameter of 0.5 mm. On this, ultrasonic bonding was performed using an Al wire having a diameter of 50 μm. Finally, an In layer 208 was attached to the n-type substrate to form an electrode. A spectral sensitivity characteristic having a peak at about 480 nm was obtained.

  Spectral sensitivity characteristics are determined by the band gap of the semiconductor. In order to generate solar light more efficiently, it is necessary to combine solar cells with sensitivity characteristics on the higher wavelength side than semiconductors such as silicon currently used in solar cells, and to fully utilize the sunlight spectrum. It is necessary to cover. Furthermore, it is necessary to easily increase the size. The solar cell in this example has a wavelength sensitivity characteristic on the high wavelength side, and is easy to make on a glass substrate, so that it is easy to increase the size.

  The hole injection electrode and the semiconductor element according to the present invention can be suitably used for, for example, a light emitting diode, a diode, a laser diode, a photodiode, or a solar cell.

It is sectional drawing which shows the typical form of this invention. It is sectional drawing which shows the semiconductor element which concerns on Example 1 of this invention. It is sectional drawing which shows the semiconductor element which concerns on Example 2 of this invention. It is a figure which shows the characteristic dependence of u value of an electrode layer in Example 2 of this invention. It is a figure which shows the film thickness dependence of the electrode layer in Example 2 of this invention. It is sectional drawing which shows the semiconductor element which concerns on Example 3 of this invention. It is sectional drawing which shows the prior art example of the semiconductor element which concerns on Example 3 of this invention. It is sectional drawing which shows the evaluation method of the semiconductor element which concerns on Example 3 of this invention. It is sectional drawing which shows the semiconductor element which concerns on Example 4 of this invention. It is sectional drawing which shows the prior art example of the semiconductor element which concerns on Example 4 of this invention. It is sectional drawing which shows the semiconductor element (light emitting diode) which concerns on Example 5 of this invention. It is a figure which shows the electrical property of the semiconductor element (light emitting diode) which concerns on Example 5 of this invention. It is a figure which shows the light emission characteristic of the semiconductor element (light emitting diode) which concerns on Example 5 of this invention. It is sectional drawing which shows the semiconductor element (light emitting diode) which concerns on Example 6 of this invention. It is a figure which shows the X-ray diffraction of the semiconductor element (light emitting diode) which concerns on Example 6 of this invention. It is a figure which shows the electrical property of the semiconductor element (light emitting diode) which concerns on Example 6 of this invention. It is sectional drawing which shows the semiconductor element (diode) which concerns on Example 7 of this invention. It is a figure which shows the electrical property of the semiconductor element (diode) which concerns on Example 7 of this invention. It is sectional drawing which shows the semiconductor element (laser diode) based on Example 8 of this invention. It is a figure which shows the LI characteristic of the semiconductor element (laser diode) which concerns on Example 8 of this invention. It is a figure which shows the light emission characteristic of the semiconductor element (laser diode) based on Example 8 of this invention. It is sectional drawing which shows the semiconductor element (photodiode) based on Example 9 of this invention. It is sectional drawing which shows the semiconductor element (solar cell) which concerns on Example 10 of this invention. In Example 1 of this invention, the value of the parameter which measured is shown. In Example 2 of this invention, the threshold voltage measured in each point of a parameter is shown. It is a schematic diagram of the crystal structure of the electrode layer of this invention. It is a schematic diagram of a ZnSe zinc blende type crystal structure.

Explanation of symbols

11 substrate 12 n-type electrode 13 n-type semiconductor 14 p-type semiconductor 15 hole injection electrode (including electrode layer)

Claims (9)

Composition formula (Pd _x Pt _y Ni _z ) _u ZnSe (where u is a real number of 4 ≦ u ≦ 6, x, y, z are x + y + z = 1, 1> x ≧ 0, 1> y ≧ 0, 1 Hole injection electrode having an electrode layer made of a material represented by
Was formed in contact with the electrode layer, the composition formula _{(Zn 1-α-β Mg} α Cd β) (Se 1-m-n S m Te n) ( where the mole ratio m, n and alpha, beta is M + n ≦ 1, 0 ≦ m ≦ 1, 0 ≦ n ≦ 0.2, 0 ≦ α ≦ 0.2, 0 ≦ β ≦ 0.2)
A semiconductor device comprising: The semiconductor element according to claim 1, wherein the semiconductor layer is a semiconductor provided with p-type characteristics by a dopant . Said semiconductor layer is made of a single crystal oriented [001] axis, and, to claim 1 or 2 [001] axis of the electrode layer is equal to or [001] axis and is substantially parallel to said semiconductor layer The semiconductor element as described. It said semiconductor layer is made of [001] axis preferentially oriented polycrystal, and claim 1 [001] axis of the electrode layer is equal to or [001] axis and is substantially parallel to the semiconductor layer or 2. The semiconductor element according to 2 . The semiconductor element according to claim 4, wherein the semiconductor layer and the electrode layer are formed on a glass substrate. Claims 1 to 5 the thickness of the electrode layer, characterized in that at 10nm or more 10μm or less
The semiconductor element in any one of. The semiconductor element according to claim 1 , wherein the semiconductor layer has a hole concentration of 1 × 10 ¹⁸ cm ⁻³ or more and 1 × 10 ²² cm ⁻³ or less. The semiconductor element according to claim 2 , wherein the semiconductor layer is a p-type semiconductor layer containing a Cu dopant. The semiconductor element is a light emitting diode, a diode, a laser diode, a photodiode,
Or it is a solar cell, The semiconductor element in any one of the Claims 1 thru | or 8 characterized by the above-mentioned.

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