JP4902680B2 - LIGHT EMITTING DEVICE HAVING SILICON OXIDE HAVING graded junction silicon nanocrystal - Google Patents

Description

  The present invention mainly relates to integrated circuit (IC) manufacturing, and more specifically, a light emitting device (EL light emitting device) including a silicon oxide film (SiOx) inclined layer including silicon nanocrystals (nc-Si) and a method for manufacturing the same. About.

FIG. 1 is a schematic block diagram of an EL light-emitting device (prior art) having a light-emitting layer made of silicon oxide rich in silicon (rich in silicon). In the current state of silicon photonics technology, silicon nanocrystals embedded in a silicon dioxide (SiO ₂ ) matrix are used. There are several methods for producing this material (silicon dioxide containing silicon nanocrystals). A simple manufacturing method is an ion implantation method in which silicon (Si) is implanted into a silicon dioxide film. Another method is plasma enhanced chemical vapor deposition (PECVD), which deposits excess silicon within the oxide. The EL light emitting device 100 includes an active light emitting layer 102 provided on a substrate bottom electrode 104 which is a conductive substrate. The conductive substrate (substrate bottom electrode 104) is, for example, a doped silicon wafer that functions as a bottom electrode.

  The active light emitting layer 102 is a film containing excess silicon deposited with silicon dioxide. Excess silicon is agglomerated in a phase different from the phase of silicon nanocrystals of about 5 nm to 10 nm. Such nano-level phases of silicon provide quantum confinement (quantum constraint) that allows radiation attenuation of the excited optical state. After the active light emitting layer 102 is deposited, a transparent upper electrode 106 such as indium tin oxide (ITO) is deposited. As a result, the EL device can perform optical output communication in a biased state.

  In such an EL device, electrified carriers (electrons and holes) are injected into the substrate bottom electrode 104 and the transparent upper electrode 106 to form an excited optical state in silicon nanocrystals (nc-Si) called excitons. Is done. When appropriately sized silicon nanocrystals are properly distributed in the silicon nanocrystal phase, excitons attenuate optical or electroluminescence. Therefore, as shown in FIG. 1, in the conventional EL device, a single light-emitting layer (active light-emitting layer 102) mainly related to carrier transport, exciton formation, and the resulting radiation attenuation is formed. .

  However, as a rule of thumb, it has been difficult to balance all such interactions within a single homogeneous thin film. Silicon nanocrystals in oxide materials that are effective for charge carrier transport are not necessarily effective in exciton radiation (emission) decay. A light emitting layer with a high concentration of silicon nanocrystal particles (eg, over 20% excess) is a better conductor than a light emitter. This is because when the silicon nanocrystals are close to each other, many nanoparticles in the excited state are consumed simply as heat or current. On the other hand, low-concentration silicon nanocrystal particles (eg, 5-10% excess) cause exciton radiation attenuation if the spacing between the internal nanoparticles is sufficient. When silicon nanocrystals present in the oxide at a high concentration are used, generation of a current sufficient to form excitons in the silicon nanocrystal particles is promoted. However, this does not necessarily mean that similar materials have equivalent efficiencies and exhibit exciton radiative decay, such as silicon oxide containing low concentrations of silicon nanocrystals.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a light-emitting device including a light-emitting layer made of silicon-rich silicon oxide that supports both radiation attenuation and exciton generation, and a method for manufacturing the same. Is to provide.

In order to solve the above problems, a method for manufacturing a light emitting device of the present invention is a method for manufacturing a light emitting device including a silicon oxide containing silicon nanocrystals,
Forming a substrate bottom electrode;
Forming a silicon oxide film layer containing silicon nanocrystals (SiOx film: x is greater than 0 and less than 2) on the substrate bottom electrode; and
Forming a transparent upper electrode on the silicon oxide film layer including the multi-layered silicon nanocrystal,
The step of forming the silicon oxide film layer containing silicon nanocrystals in a multi-layered manner is as follows: an outer layer sandwiches an inner layer, and the inner layer has a relatively low concentration of silicon nanocrystals. A silicon oxide film layer containing crystals is formed.

  According to said invention, the silicon oxide layer containing a silicon nanocrystal is formed in multiple layers, and the silicon nanocrystal density | concentration is relatively low as the inner layer is the layer. The inner layer is sandwiched between the outer layers. Accordingly, it is possible to manufacture a light emitting device including a light emitting layer made of silicon-rich silicon oxide that supports both radiation attenuation and exciton generation.

  In the method for manufacturing a light-emitting device according to the present invention, the step of forming the silicon oxide film layer including the silicon nanocrystal in the outer layer has a higher conductivity (dielectric constant) than the inner layer sandwiched between the outer layers. A silicon oxide film layer including silicon nanocrystals having a layer may be formed.

  In the method for manufacturing a light emitting device according to the present invention, the step of forming the silicon oxide film layer containing silicon nanocrystals in a multilayer may be formed by a high density plasma enhanced chemical vapor deposition (HDPECVD) process.

In the method of manufacturing the light emitting device of the present invention, by the HDPECVD process step of multilayer forming the silicon oxide film layer comprising silicon nanocrystals includes a step of forming a silicon oxide film (SiOx) layer,
The step of forming the silicon oxide film includes
Supplying power to the upper electrode at a frequency of 13.56-300 MHz and a power density of less than 10 W / cm ² ;
Supplying power to the lower electrode at a frequency of 50 kHz to 13.56 MHz and a power density of 3 W / cm ² or less;
Using an atmospheric pressure of 1 to 500 mTorr;
Supplying an oxygen source gas;
And supplying a Si source gas together with hydrogen.

In the method for manufacturing a light emitting device of the present invention, the step of forming a silicon oxide film layer containing silicon nanocrystals by the HDPECVD process is performed by an annealing step and an annealing step after the step of forming the silicon oxide film. And a step of filling the oxide film with silicon nanocrystals.

In the method for manufacturing a light emitting device of the present invention, in the step of supplying the oxygen source gas, an oxygen source gas selected from the group consisting of N ₂ O, NO, O ₂ , and O ₃ may be supplied.

In the method for manufacturing a light emitting device of the present invention, the step of supplying the Si source gas includes Si ₃ N _X (N is 1 to 4) and Si ₃ H _X R _4-X (X is 0 to 3). , R may be supplied with a gas selected from the group consisting of Cl, Br, and I selected from the group consisting of I.

In the method for manufacturing a light emitting device according to the present invention, the step of forming the silicon oxide film layer containing the silicon nanocrystal in a multilayer is to change the ratio of the Si source gas to the oxygen source gas within a range of 0.1 to 10. Accordingly, the conductivity of each layer can be selected.

In the method for manufacturing a light emitting device according to the present invention, the step of forming the silicon oxide film layer including the silicon nanocrystals in a multi-layer is performed by changing the ratio of the Si source gas to the hydrogen within a range of 0.1 to 100. The conductivity of each layer can be selected.

In the method for manufacturing a light emitting device of the present invention, the step of forming a silicon oxide film layer containing silicon nanocrystals by the HDPECVD process has a plasma density higher than 1 × 10 ¹¹ cm ⁻³ at an electron temperature of less than 10 eV. Can be used.

  In the method for manufacturing a light emitting device of the present invention, in the step of forming the silicon oxide film layer containing silicon nanocrystals in a multilayer manner, the silicon excess concentration of each layer may be 5 to 30%.

In the method for manufacturing a light emitting device according to the present invention, in the step of forming the silicon oxide film layer including the silicon nanocrystal in a multilayer, each layer is formed of Si _J O ₂ (J is 1.05 or more and 1.3 or less). Further, the outer layer may sandwich the inner layer having a relatively low silicon excess (abundance).

  In the method for manufacturing a light emitting device according to the present invention, in the step of forming the silicon oxide film layer containing silicon nanocrystals in a multilayer manner, the total thickness of the silicon oxide film layer containing silicon nanocrystals may be 50 to 500 nm.

  In the method for manufacturing a light emitting device according to the present invention, the step of forming the silicon oxide film layer including the silicon nanocrystals in a multilayer includes forming a silicon oxide film layer including the three silicon nanocrystals and increasing the thickness of the outer two layers. , Respectively, may be 1 to 20% of the total layer thickness.

  In the method for manufacturing a light emitting device of the present invention, the step of forming the silicon oxide film layer containing silicon nanocrystals in a multilayer may form a silicon oxide film layer containing silicon nanocrystals having a diameter of 2 to 10 nm in each layer.

  In the method for manufacturing a light emitting device according to the present invention, the step of forming the silicon oxide film layer including the silicon nanocrystals in a multilayered manner includes silicon nanocrystals in which carrier injection energy is gradually graded between the silicon oxide film layers including the silicon nanocrystals. A silicon oxide film layer containing may be formed.

In order to solve the above problems, a light-emitting device of the present invention is a light-emitting device including a silicon oxide containing silicon nanocrystals,
A substrate bottom electrode;
A silicon oxide film layer (SiOx film: x is greater than 0 and less than 2) formed on the substrate bottom electrode and including multilayer silicon nanocrystals;
A transparent upper electrode formed on the silicon oxide film layer containing the multilayer silicon nanocrystal,
The silicon oxide film layer including multilayer silicon nanocrystals is characterized in that the outer layer sandwiches the inner layer, and the silicon nanocrystal concentration of the inner layer is relatively low.

  In the light emitting device of the present invention, the silicon oxide film layer including the outer silicon nanocrystals may have a higher conductivity than the silicon oxide film layer including the inner silicon nanocrystals sandwiched therebetween.

  In the light emitting device of the present invention, each layer of the silicon oxide film layer containing the silicon nanocrystal may have a silicon excess concentration of 5 to 30%.

In the light emitting device of the present invention, each of the silicon oxide film layers including the silicon nanocrystals is formed of Si _J O ₂ (J is 1.05 or more and 1.3 or less), and more outside. The layer may sandwich an inner layer with a relatively low silicon excess.

  In the light emitting device of the present invention, the total thickness of the silicon oxide film layer including the silicon nanocrystal may be 50 to 500 nm.

In the light emitting device of the present invention, the silicon oxide film layer containing the silicon nanocrystal is three layers,
The outer two layers may each have a thickness of 1 to 20% of the total thickness.

  In the light emitting device of the present invention, each layer of the silicon oxide film layer including the silicon nanocrystal may have a silicon nanocrystal having a diameter of 2 to 10 nm.

  In the light emitting device and the method for manufacturing the light emitting device of the present invention, as described above, the silicon oxide film layer including multiple layers of silicon nanocrystals has the outer layer sandwiching the inner layer, and the inner layer silicon nanocrystals. The crystal concentration is relatively low. Therefore, there is an effect that it is possible to realize a light emitting device including a light emitting layer made of silicon-excess silicon oxide that supports both radiation attenuation and exciton generation, and a manufacturing method thereof.

It is sectional drawing which shows schematic structure of the EL apparatus provided with the light emitting layer which consists of the conventional silicon excess silicon dioxide. It is a fragmentary sectional view of EL device provided with silicon oxide containing the silicon nanocrystal of the present invention. It is a fragmentary sectional view which shows the 1st modification of EL device provided with the silicon oxide containing the silicon nanocrystal of FIG. It is a figure which shows the density | concentration of the silicon nanocrystal of the silicon oxide film containing a silicon nanocrystal in the EL apparatus of FIG. 2 and FIG. It is a figure which shows the outline of the injection | pouring energy barrier in the conventional EL apparatus of FIG. 1 provided with the SRSO film | membrane. It is a figure which shows the outline of the injection | pouring energy barrier in the EL apparatus of FIG. It is a flowchart which shows the manufacturing method of EL device provided with the silicon oxide containing a silicon nanocrystal. It is the schematic of a high concentration plasma system provided with the inductively coupled plasma source.

The EL device of the present invention enhances optical emission by controlling charge injection characteristics and EL efficiency during active layer deposition. The active layer uses silane (SiH ₄ ) and nitrous oxide (N ₂ O) along with helium (He) and hydrogen (H ₂ ), using high-pressure (HP) plasma chemistry of silicon-rich silicon dioxide film (SRSO film). It can be formed by deposition (evaporation) by vapor deposition (PECVD). Further, in this active layer, in addition to the stoichiometric amount of silicon necessary for forming silicon dioxide (SiO ₂ ), an excessive amount (excess degree) in which excess silicon is deposited is, for example, relative to nitrous oxide. Controlled by silane ratio.

  Therefore, according to the present invention. A method for manufacturing a silicon oxide EL device including silicon nanocrystals can be provided. The EL device manufacturing method of the present invention includes a step of forming a substrate bottom electrode, and a silicon oxide film layer containing silicon nanocrystals (SiOx film: x is greater than 0 and less than 2) on the substrate bottom electrode. A step of forming a multilayer. More specifically, each layer of silicon oxide layer that includes silicon nanocrystals has a silicon excess concentration of about 5-30%. The silicon oxide film layer containing silicon nanocrystals is a multilayer stack. The outer layer of the silicon oxide film layer containing silicon nanocrystals sandwiches the inner layer having relatively low concentration of silicon nanocrystals. In addition, the silicon oxide film layer including the outer silicon nanocrystal has higher conductivity than the inner layer sandwiched between the outer layers. A transparent upper electrode is formed on the silicon oxide film layer including multilayer silicon nanocrystals.

A silicon oxide layer containing multiple layers of silicon nanocrystals. Deposited by a high density plasma enhanced chemical vapor deposition process (HD PECVD process). HDPECVD process, first, depositing a silicon oxide film layer, followed by an annealing treatment (annealing step), a process for silicon nanocrystals state write or a buried silicon oxide film layer. Here, the diameter of the silicon nanocrystal is 2 to 10 nm (2 nm or more and 10 nm or less).

  In the EL device manufacturing method of the present invention, the total thickness of the silicon oxide film layer including the silicon nanocrystals formed in multiple layers may be 50 nm to 500 nm. Further, for example, when there are three silicon oxide film layers containing silicon nanocrystals, the outer two layer thicknesses may occupy 1 to 20% of the total layer thickness.

  Hereinafter, a light emitting device (EL device) including silicon oxide containing silicon nanocrystals will be described in detail.

  FIG. 2 is a partial cross-sectional view of an EL device including a silicon oxide containing silicon nanocrystals of the present invention. The EL device 200 includes a substrate bottom electrode 202, a silicon oxide film layer 204 including silicon nanocrystals, and a transparent upper electrode 206. The substrate bottom electrode 202 is formed on a silicon oxide film (SiOx) 204 including multilayer silicon nanocrystals. Here, x of SiOx is greater than 0 and less than 2. In this embodiment, the silicon oxide film (SiOx) layer 204 containing silicon nanocrystals is composed of three layers. Specifically, an inner layer 204b having a low concentration of silicon nanocrystals is sandwiched between two outer layers 204a1 and 204a2 of a silicon oxide film layer 204 containing silicon nanocrystals. Hereinafter, the silicon oxide film layer 204 containing silicon nanocrystals may be referred to as an nc-SiSiOx film layer or a silicon oxide film layer containing nc-Si. A silicon oxide film layer 204 containing silicon nanocrystals is formed on the transparent upper electrode 206. The transparent upper electrode 206 may be made of, for example, ITO (indium tin oxide), or may include a thin film metal layer.

  FIG. 3 is a partial cross-sectional view showing a first modification of the silicon oxide EL device (EL device 200) including the silicon nanocrystal of FIG. The silicon oxide film layer 204 including silicon nanocrystals formed in the EL device 200 is not limited to three layers as shown in FIG. 2, but is formed of three or more layers as shown in FIG. Also good. In the EL device 200 of FIG. 3, the silicon oxide layer 204 containing silicon nanocrystals includes two outermost layers 204 n (a layer 204 n adjacent to the substrate electrode 202 and a layer 204 n adjacent to the upper electrode 206). , Outside the inner layer 204 (n-1) adjacent to them and sandwiching the inner layer 204 (n-1). The outer layer 204n has a higher concentration of silicon nanocrystals than the inner layer 204 (n-1). Similarly, the layer 204 (n−1) is outside the inner layer 204 (n−2) and sandwiches the inner layer 204 (n−2). In this way, the silicon oxide film layer 204 containing silicon nanocrystals can have a gradient in excess silicon concentration (content).

In FIG. 2 or FIG. 3, each layer of the silicon oxide film layer 204 containing silicon nanocrystals is defined by, for example, Si _J O ₂ (J is 1.05 or more and 1.3 or less). It contains excessively. Moreover, the outer layer sandwiches the inner layer having a lower silicon excess. That is, the outer layer has a higher silicon concentration and the inner layer has a lower silicon concentration. For example, each layer of the silicon oxide layer 204 containing silicon nanocrystals has a silicon excess concentration of about 5-30%. As described above, the outer layer of the silicon oxide film layer 204 containing silicon nanocrystals has higher conductivity than the inner layer sandwiched between the layers. The diameter of the silicon nanocrystal included in the silicon oxide film layer 204 including the silicon nanocrystal is, for example, about 2 nm to 10 nm.

Furthermore, the density (content) and size (diameter) of silicon nanocrystals may be changed from layer to layer. For example, the size of the silicon nanoparticles may be changed according to the density of the silicon nanoparticles. Thus, it is understood that the difference between layers in the silicon oxide film layer 204 containing silicon nanoparticles is a difference in silicon “excess (abundance)” and an excess effect due to the size and density of silicon nanocrystals. it can.
As shown in FIG. 2, the total thickness 208 of the silicon oxide film layer 204 including multilayer silicon nanocrystals is, for example, 50 nm to 500 nm. In particular, in the case of the EL device 200 of FIG. 2, the silicon oxide film layer 204 including silicon nanocrystals is three layers. The outer layer 204a1 has a layer thickness 210a1 and 204a2 has a layer thickness 210a2. Further, the outer layer 204a1 and the outer layer 204a2 may each occupy 1 to 20% of the total thickness 208 of the silicon oxide film layer 204 including silicon nanocrystals. Note that the silicon oxide film layer 204 containing silicon nanocrystals may or may not be symmetric in terms of silicon concentration and thickness. For example, the top layer 204a2 may be thinner than the bottom layer 204a1. Of course, the silicon oxide film layer 204 including silicon nanocrystals disposed between the substrate bottom electrode 202 and the transparent upper electrode 206 does not have to be an odd number.

  The EL device 200 shown in FIGS. 2 and 3 is characterized in that the optical emission function is enhanced by controlling the charge injection characteristics and the EL efficiency shown during the deposition of the active layer. The silicon oxide layer 204 (active layer) containing silicon nanocrystals is deposited using high pressure (HP) plasma enhanced chemical vapor deposition (PECVD) of silicon-rich silicon dioxide film (SRSO film). For example, silane (SiH4) and nitrous oxide (N2O) are used together with helium (He) and hydrogen (H2). The silicon oxide layer 204 containing silicon nanocrystals has an excess of silicon deposited in addition to the stoichiometric amount necessary for silicon dioxide formation. In the above example, the excess silicon can be controlled by the ratio of silane to nitrous oxide.

  If silicon-rich silicon oxide (SRSO) with an excess silicon concentration of 5-30%, preferably 10-20% is used, the silicon substrate electrode (substrate bottom electrode 202) and ITO electrode (transparent top electrode 206) The carrier injection barrier is also observed. This result is reasonable considering that the energy barrier for injection into the EL light-emitting layer is considered to be a composite value of an oxide barrier and a silicon nanocrystal barrier for each electrode. In contrast to injection into pure oxide, composite SRSO materials (silicon-rich silicon oxide with excess silicon concentration) have a lower energy barrier because they contain nanocrystalline silicon. The conclusion that the amount of barrier height reduction corresponds to the silicon nanocrystal concentration is strongly supported by the acquired data, but the exact effect has not been established.

  The implantation energy into EL materials containing high concentrations of silicon nanocrystals is lower, but materials containing high excess silicon nanocrystals (15-20%) contain 5-10% overconcentration silicon nanocrystals. The EL material is less efficient than the material. Such a result is due to the fact that there is a non-radiative path in high concentrations of silicon nanocrystal material. In the case of higher density silicon nanocrystals, this can be reasonably explained by considering that most acts more “silicon like”. Considering such a result from the viewpoint of quantum confinement, it is as follows. That is, if the exciton diffusion distance is larger than the silicon nanocrystal particle size, the excitons with the radiation ability of the specific particles should not overlap so that they do not substantially decay non-radiatively with the neighboring particles. Is essential. Therefore, particle separation is an important factor for luminous efficiency. That is, high-concentration silicon nanocrystals do not contribute to light emission. And the quantum confinement of excitons contributing to radiation has a better effect in the case of low density silicon nanocrystal distribution.

  FIG. 4 is a diagram showing the concentration of silicon nanocrystals in a silicon oxide film containing silicon nanocrystals in the EL device 200 of FIGS. 2 and 3. The present inventors have developed a novel light emitting layer configuration that can control two factors, radiation effect and injection energy, to enhance the EL efficiency and reduce the barrier. Theoretically, it is sufficient that silicon nanocrystals having a lower concentration than the outer surface of the EL film are contained inside the EL film.

  The manufacture of silicon oxide films containing silicon nanocrystals is due to the residual oxides present in the film and the local heat treatment atmosphere once the particle density and particle size have been maximized once by annealing. Therefore, there is another problem that the particles are easily oxidized. Therefore, since high concentration silicon nanocrystals are offset by oxidation, cap layers formed on both surfaces in contact with excess silicon tend to be improved. Each side of the emissive layer with increased concentration of silicon nanocrystals has the beneficial properties of cap layer and injection barrier control.

  One way to approximate the side of FIG. 4 is to deposit three components on the electrode substrate as shown in FIG. The first layer (bottom layer 204a1) has a relatively high content of silicon nanocrystals (eg, 15-20% excess), and the thickness 210a of the first layer (bottom layer 204a1) is about 10 nm. is there. The bottom layer 204 a 1 functions as an injection medium for the substrate bottom electrode 202. The second layer (intermediate layer 204b) is an exciton light-emitting layer that has a relatively low content of silicon nanocrystals (for example, about 5 to 10% excess) and appropriately maintains quantum confinement (quantum constraint). Function. The thickness of the light emitting layer is, for example, 15 to 20 nm. The third layer (top layer 204a2) is an injection medium for the transparent upper electrode 206, has a relatively high content of silicon nanocrystals (for example, 15 to 20% excess), and has a thickness of about 10 nm. .

  During annealing, there is layer diffusion (layer diffusion) from a high concentration layer to a low concentration layer. This layer diffusion serves to create a stepwise injection energy gradient of carrier transport from the non-recombinant transport (cap layer) formed in the central region to the radiative excitons. In this way, a gradual barrier is formed, as opposed to a sharp Schottky-type barrier. Such an EL device can considerably increase the degree of freedom in setting the turn-on voltage and the radiation effect.

  FIG. 5A is a diagram showing an outline of an implantation energy barrier in the conventional EL device of FIG. 1 having an SRSO film. FIG. 5B is a diagram schematically showing an implantation energy barrier in the EL device 200 of FIG.

In the case of a silicon oxide layer composite including multilayer silicon nanocrystals (silicon oxide layer 204 including multilayer silicon nanocrystals), since the ITO functions as a hole injector, the energy barrier structure in the bias state is As shown in FIG. 5B. On the other hand, in the case of a light emitting device including an oxide film layer including a single layer of silicon nanocrystal, the energy barrier structure in the sample bias state is as shown in FIG. 5A. Step-like carriers are injected between the valence band (VB) and the conduction band (CB). In the case of providing the silicon oxide film layer 204 including such multilayer silicon nanocrystals, there is another advantage that the thickness of each injection layer can be set so as to cancel the difference between electrons and holes. For example, assuming that the electron transfer in the high-concentration silicon nanocrystal injection material is larger than the hole transfer, the thickness of the layer involved in electron injection is the amount of injection in the light-emitting layer of the low-concentration silicon nanocrystal. Can be increased to balance.
FIG. 6 is a flowchart showing a method of manufacturing an EL device including silicon oxide containing silicon nanocrystals. In the manufacturing method shown in FIG. 9, serial numbers are given to the respective steps for the sake of clarity, but the given numbers do not indicate the order of the steps. That is, as a matter of course, some of the steps in the drawing may be omitted, may be performed simultaneously, or may be performed without maintaining an accurate order. The manufacturing method of FIG. 9 starts from S600.

  First, in S602, a bottom electrode substrate is formed (prepared). In S604, a silicon oxide film layer (SiOx film: x is greater than 0 and less than 2) including multiple layers of silicon nanocrystals is formed on the bottom electrode. With this silicon film, the outer layer sandwiches the inner layer containing a relatively low concentration of silicon nanocrystals. For example, the diameter of the silicon nanocrystal is 2 nm to 10 nm. In S606, on a silicon oxide film layer including multiple layers of silicon nanocrystals. A transparent upper electrode is formed.

In the step of forming a silicon oxide film layer including silicon nanocrystals in S604, the silicon excess concentration in each layer of the silicon oxide film layer including silicon nanocrystals may be about 5 to 30%. As described above, the silicon oxide film layer including each silicon nanocrystal includes silicon excessively as indicated by Si _J O 2 (J is approximately 1.05 to 1.3), and is formed on the outer side. This layer sandwiches the inner layer having a low silicon excess. Further, in the step of forming a silicon oxide film layer including multi-layered silicon nanocrystals in S604, a silicon oxide film layer including silicon nanocrystals as outer layers having higher conductivity than the sandwiched inner layer is formed. May be.

Furthermore, in the step of forming a silicon oxide film layer including multi-layered silicon nanocrystals in S604, a thin film layer can be deposited by a high density plasma enhanced chemical vapor deposition process (HDPECVD process). The high density plasma enhanced chemical vapor deposition process can be distinguished from other plasma enhanced growth methods in that it uses a plasma density higher than 1 × 10 ¹¹ cm ⁻³ at an electron temperature of less than 10 eV.

The HDPECVD process of S604 may include the following sub-steps. Specifically, in S604, power having a frequency of 13.56 MHz to 300 MHz and a power density of less than 10 W / cm ² is supplied to the upper electrode. In step 604b, power having a frequency of 50 kHz to 13.56 MHz and a power density of 3 W / cm ² or less is supplied to the lower electrode. In S604c, a pressure of 1 mTorr to 500 mTorr is used. In S604d, an oxygen source gas is supplied. In S604d, an Si source gas is supplied together with hydrogen (H2). By such sub-step processing, a silicon oxide film layer (SiOx layer) is formed in S604f. After the formation of the silicon oxide film layer in S604f, annealing is performed in S604g. By this annealing, in S604h, silicon nanocrystals are embedded in the silicon oxide film layer.

As the oxygen source gas supplied in S604d, for example, an oxygen source gas such as N ₂ O, NO, O ₂ , or O ₃ can be used. On the other hand, it is supplied in S604d. The Si source gas is, for example, Si _N H _{2N + 2} (N is 1 or more and 4 or less) or SiH _x R _4-x (X is 0 or more and 3 or less, and R is a chlorine atom (Cl) or a bromine atom (Br). Or it may be an iodine atom (I).

The conductivity of each layer of the silicon oxide film layer including the multilayered silicon nanocrystal formed in S604 is, for example, in accordance with changing the ratio of the Si source gas to the oxygen source gas in the range of 0.1 to 10 . Select . Further, the conductivity of each thin film layer formed in S604 is selected in accordance with, for example, changing the ratio of the Si source gas to hydrogen in the range of 0.1 to 100 .
In addition, the total thickness of the silicon oxide film layer including multi-layered silicon nanocrystals formed in S604 may be about 50 nm to 500 nm. Moreover, when forming the silicon oxide film layer containing three silicon nanocrystals in S604, the layer thickness of each outer layer may occupy 1 to 20% of the total layer thickness.

In step S604, a silicon oxide film layer including silicon nanocrystals may be formed in which carrier injection energy gradient is gradually performed between silicon oxide films including silicon nanocrystals. Here, the slope of the barrier indicates that the height of the barrier changes relatively as shown in FIG. 5B. The height of the barrier can be adjusted by changing the size (diameter) and density of the silicon nanoparticles from one layer to the adjacent layer. The size and density of the nanoparticles can be changed by appropriately controlling deposition parameters such as gas flow rate (gas flow rate), pressure, and temperature of silane (SiH ₄ ) relative to nitrous oxide (N ₂ O) Can do.

  FIG. 7 is a schematic diagram of a high concentration plasma system (HDP system) having an inductively coupled plasma source. The high concentration plasma system of FIG. 7 can be used for the deposition of silicon oxide containing silicon nanocrystals by the high density plasma enhanced chemical vapor deposition (HDPECVD) process described above. The upper electrode 1 is driven by a high frequency (RF) power source 2 and the lower electrode 3 is driven by a low frequency power source 4. The high frequency power is connected to the upper electrode 1 through a matching circuit 5 and a high pass filter 7 from a high frequency power source 2 using a high density inductively coupled plasma (ICP) source. The power to the lower electrode 3 through the low pass filter 9 and the matched transformer 11 can be changed independently of the upper electrode 1.

The power frequency supplied to the upper electrode 1 can be about 13.56 MHz to about 300 MHz based on the ICP design. The power frequency supplied to the lower electrode 3 is about 50 KHz to control ion energy. It can be about 13.56 MHz. The pressure can be 500 mTorr or less. The power supplied to the upper electrode 1 can be about 10 W / cm ² and the power to the lower electrode 3 can be about 3 W / cm ² .

  One interesting feature of the HDP system is that there is no induction coil exposed to the plasma and removes impurities induced in the source. In the HDP system, power control for the upper electrode 1 and the lower electrode 3 can be performed independently. Since the upper electrode 1 and the lower electrode 3 are not exposed to plasma, it is not necessary to adjust the potential of the HDP system body using a variable capacitor. That is, there is no crosstalk between the upper electrode 1 and the lower electrode 3, and the plasma potential is low, usually less than 20V. The potential of the HDP system is a float type potential and is based on system design and power coupling effects.

The HDP means in the HDP system is a true high-density plasma process with an electron concentration greater than 1 × 10 ¹¹ cm ⁻³ and an electron temperature of less than 10 eV. Moreover, the HDP system maintains different biases between the capacitor connected to the upper electrode 1 and the system body, as in many high density plasma systems and conventional designs such as capacitively coupled plasma means. There is no need. Further, as described above, high frequency (RF) power is supplied to the upper electrode 1, and low frequency (LF) power is supplied to the lower electrode 3.

  In general, the high density plasma process in the present invention is effective in the formation of active hydrogen species for the generation and control (size and density) of silicon nanocrystal particles. The plasma generated by active hydrogen species also affects the crystallinity of the formed silicon nanocrystal particles. The hydrogen plasma minimizes the amorphous phase by effective etching of the formed silicon nanoparticles. be able to. Moreover, hydrogen irradiation (hydrogen bombardment) can effectively destroy silane in a plasma for generating and controlling silicon nanoparticles. The addition of hydrogen was effective in lowering the particle growth temperature of the microcrystalline silicon film. The high density plasma produced by hydrogen species can further enhance the optical performance of silicon oxide films containing silicon nanocrystals by in situ passivation of imperfect bonds. Incomplete coupling may reduce PL / EL through absorption and non-radiative recombination processes. The addition of hydrogen plasma is particularly effective for the formation of silicon nanoparticles that emit PL signals at wavelengths above 600 nm. It is. Increasing the density and size of silicon nanoparticles due to active hydrogen species in high density plasma leads to improved PL performance at wavelengths from 400 nm to 900 nm.

  The EL device including the silicon oxide containing silicon nanocrystals and the manufacturing method thereof are as described above. The details of the characteristics, structure, and manufacturing method of the EL device in the specification are only examples of the present invention. The present invention is not limited to the examples in the specification. Other variations and embodiments of the invention will be found to those skilled in the art.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

[Related applications]
This application is a continuation-in-part application (CIP application) of US patent application No. 12 / 126,430 filed invented by Huang et al. (Filed on May 23, 2008, light-emitting device with an insulating film containing silicon nanocrystals) ). US patent application Ser. No. 12 / 126,430 is a continuation-in-part of the following applications:
-US patent application No. 11 / 418,273 invented by Pooran Joshi et al. (Filed May 4, 2006, silicon oxide film containing silicon nanocrystals).
US patent application Ser. No. 11 / 327,612 invented by Pooran Joshi et al. (Filed Dec. 15, 2004, accelerated thin film oxidation process).
• US patent application 11 / 013,605 invented by Pooran Joshi et al. (Filed December 15, 2004, high density plasma hydrogenation).
US patent application No. 11 / 139,726 invented by Pooran Joshi et al. (Filed May 26, 2005, promoting high concentration plasma oxidation of gate oxide).
US patent application 10 / 871,939 invented by Pooran Joshi et al. (Filed Jun. 17, 2004, high-density plasma process for silicon thin films: US Pat. No. 7,718,663).
A US patent application No. 10 / 801,374 invented by Pooran Joshi et al. (Filed on Mar. 15, 2004, manufacturing method of oxide thin film: US Pat. No. 7,087,537).
All the above-mentioned applications are incorporated as references for this application.

  The present invention can be suitably used for a light emitting device, an integrated circuit (IC), and the like.

1 Upper electrode 3 Lower electrode 200 EL device (light emitting device)
202 Substrate bottom electrode 204 Silicon oxide film layer 206 containing silicon nanocrystals Transparent upper electrode

Claims (21)

A method of manufacturing a light-emitting device including silicon oxide containing silicon nanocrystals,
Forming a substrate bottom electrode;
Forming a silicon oxide film layer containing silicon nanocrystals (SiOx film: x is greater than 0 and less than 2) on the substrate bottom electrode; and
Forming a transparent upper electrode on the silicon oxide film layer including the multi-layered silicon nanocrystal,
The step of forming the silicon oxide film layer containing silicon nanocrystals in a multi-layered manner is as follows: an outer layer sandwiches an inner layer, and the inner layer has a relatively low concentration of silicon nanocrystals. A method for manufacturing a light-emitting device, comprising forming a silicon oxide film layer containing crystals.   The step of forming the silicon oxide film layer including the silicon nanocrystal in a multilayer form the silicon oxide film layer including the silicon nanocrystal having the outer layer having higher conductivity than the inner layer sandwiched between the outer layers. The method for manufacturing a light emitting device according to claim 1.   3. The light emitting device according to claim 1, wherein in the step of forming the silicon oxide film layer containing silicon nanocrystals in a multilayer manner, the film is deposited by a high density plasma enhanced chemical vapor deposition (HDPECVD) process. Manufacturing method. The step of forming a silicon oxide film layer containing silicon nanocrystals by the HDPECVD process includes a step of forming a silicon oxide film (SiOx) layer,
The step of forming the silicon oxide film includes
Supplying power to the upper electrode at a frequency of 13.56-300 MHz and a power density of less than 10 W / cm ² ;
Supplying power to the lower electrode at a frequency of 50 kHz to 13.56 MHz and a power density of 3 W / cm ² or less;
Using an atmospheric pressure of 1 to 500 mTorr;
Supplying an oxygen source gas;
The method for manufacturing a light emitting device according to claim 3, further comprising: supplying a Si source gas together with hydrogen.   In the step of forming a silicon oxide film layer including silicon nanocrystals by the HDPECVD process, a silicon nanocrystal is embedded in the silicon oxide film by an annealing step and an annealing step after the step of forming the silicon oxide film. The method for manufacturing a light emitting device according to claim 4, further comprising a step of setting the state. 5. The light emitting device according to claim 4, wherein in the step of supplying the oxygen source gas, an oxygen source gas selected from the group consisting of N ₂ O, NO, O ₂ , and O ₃ is supplied. Method. The step of supplying the Si source gas includes Si _N H _{2N + 2} (N is 1 or more and 4 or less) and SiH _x R _4-x (X is 0 or more and 3 or less, and R is a group consisting of Cl, Br, and I) The method for manufacturing a light-emitting device according to claim 4, wherein a gas selected from the group consisting of a more selected element is supplied. The step of forming a silicon oxide film layer containing silicon nanocrystals by the HDPECVD process uses a plasma density higher than 1 × 10 ¹¹ cm ⁻³ at an electron temperature of less than 10 eV. The manufacturing method of the light-emitting device of description.   2. The method of manufacturing a light emitting device according to claim 1, wherein in the step of forming the silicon oxide film layer containing silicon nanocrystals in multiple layers, an excessive silicon concentration of each layer is set to 5 to 30%. The step of forming the silicon oxide film layer containing silicon nanocrystals in a multi-layered manner includes forming each layer from Si _J O ₂ (J is 1.05 or more and 1.3 or less), and the outer layers are relative to each other. The method for manufacturing a light-emitting device according to claim 1, wherein an inner layer having a low silicon excess is sandwiched.   2. The light emitting device according to claim 1, wherein the step of forming the silicon oxide film layer including the silicon nanocrystals in a multilayer form sets the total thickness of the silicon oxide film layer including the silicon nanocrystals to 50 to 500 nm. Device manufacturing method. The step of forming the silicon oxide film layer containing silicon nanocrystals in a multilayer form forms a silicon oxide film layer containing three silicon nanocrystals, and the outer two layers have a thickness of 1 to 20 of the total thickness. The method for manufacturing a light emitting device according to claim 11 , wherein   2. The light emitting device according to claim 1, wherein the step of forming a plurality of silicon oxide film layers including silicon nanocrystals includes forming a silicon oxide film layer including silicon nanocrystals having a diameter of 2 to 10 nm in each layer. Production method.   The step of forming the silicon oxide film layer including the silicon nanocrystal in a multilayer includes forming a silicon oxide film layer including the silicon nanocrystal in which the carrier injection energy is gradually graded between the silicon oxide film layers including the silicon nanocrystal. The method of manufacturing a light emitting device according to claim 1. A light-emitting device comprising silicon oxide containing silicon nanocrystals,
A substrate bottom electrode;
A silicon oxide film layer (SiOx film: x is greater than 0 and less than 2) formed on the substrate bottom electrode and including multilayer silicon nanocrystals;
A transparent upper electrode formed on the silicon oxide film layer containing the multilayer silicon nanocrystal,
A silicon oxide film layer including multiple layers of silicon nanocrystals, wherein the outer layer sandwiches the inner layer, and the silicon nanocrystal concentration of the inner layer is relatively low. The light emitting device according to claim 15 , wherein the silicon oxide film layer including the outer silicon nanocrystal has higher conductivity than the silicon oxide film layer including the inner silicon nanocrystal sandwiched therebetween. 16. The light emitting device according to claim 15 , wherein each layer of the silicon oxide film layer containing silicon nanocrystals has a silicon excess concentration of 5 to 30%. Each layer of the silicon oxide film layer including the silicon nanocrystal is formed of Si _J O ₂ (J is 1.05 or more and 1.3 or less), and the outer layer is relatively silicon. The light emitting device according to claim 15 , wherein an inner layer having a low excess is sandwiched. 16. The light emitting device according to claim 15 , wherein the total thickness of the silicon oxide film layer containing silicon nanocrystals is 50 to 500 nm. The silicon oxide film layer containing the silicon nanocrystal is three layers,
The light emitting device according to claim 19 , wherein the outer two layers each have a thickness of 1 to 20% of the total thickness. 16. The light emitting device according to claim 15 , wherein each layer of the silicon oxide film layer containing silicon nanocrystals has silicon nanocrystals having a diameter of 2 to 10 nm.

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