JP2017503323A - Solid electrolyte and barrier on lithium metal and method - Google Patents

Abstract

A method of manufacturing an electrochemical device comprising a lithium metal electrode includes providing a substrate having a lithium metal electrode on a surface and depositing a first dielectric material layer on the lithium metal electrode, the method comprising: Depositing and maintaining a nitrogen plasma on the first dielectric material layer after depositing the first layer and depositing the first layer, which is sputtering Li3PO4 in Providing a first layer of ion bombardment and mixing and inducing nitrogen therein, and inducing and maintaining; and after the deposition, inducing and maintaining steps, the ion bombarded first dielectric material layer Depositing a second dielectric material layer thereon, sputtering Li3PO4 in a nitrogen-containing environment; Depositing a layer. The electrochemical device can include a barrier layer between the lithium metal electrode and the LiPON electrolyte. A tool configured for manufacturing an electrochemical device comprising a lithium metal electrode is also described.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is related to US Provisional Patent Application No. 13 / 523,790, filed June 14, 2012, which claims the benefit of US Provisional Patent Application No. 61 / 498,480, filed June 17, 2011. Both of which are hereby incorporated by reference in their entirety.
Embodiments of the present disclosure relate generally to thin film deposition, and more particularly to a method of depositing a solid electrolyte layer, such as LiPON, on lithium metal, and related devices and deposition apparatus.

  FIG. 1 shows a cross-sectional view of a typical thin film battery (TFB). A TFB device structure 100 having an anode current collector 103 and a cathode current collector 102 is formed on a substrate 101 followed by a cathode 104, an electrolyte 105, and an anode 106. And the anode can be manufactured in the reverse order. Furthermore, the cathode current collector (CCC) and the anode current collector (ACC) can be deposited separately. For example, CCC can be deposited before the cathode and ACC can be deposited after the electrolyte. The device can be covered by an encapsulating layer 107 to protect the environmentally sensitive layer from oxidizing agents. See, for example, N. J. Dudney, Materials Science and Engineering B 1 16, (2005) 245-249. Note that these component layers are not drawn to scale in the TFB device shown in FIG.

In a typical TFB device structure as shown in FIG. 1, an electrolyte (a dielectric material such as Lithium Phosphorous Oxinitride (LiPON)) is sandwiched between two electrodes (anode and cathode). . LiPON is a chemically stable solid electrolyte and has a wide working voltage range (up to 5.5 V) and relatively high ionic conductivity (1-2 μsec / cm). Solid batteries, especially thin film types, contain LiPON as the electrolyte, so the cell is capable of over 20,000 charge / discharge cycles with only 0.001% capacity loss / cycle. The conventional method used to deposit LiPON is physical vapor deposition (PVD) radio frequency (RF) sputtering of a Li ₃ PO ₄ target in an N ₂ environment.
In a solid battery structure in which Li is included as the anode material, the reactivity of Li presents a significant challenge in making the battery. Such a difficult situation arises when it is necessary to protect the Li anode in the conventional order of manufacturing the battery, for example, in a thin film (vacuum deposited) solid battery, a cathode current collector, cathode, electrolyte on the substrate The anodes are formed sequentially in this order, with the top Li anode being coated in some way to protect the Li anode from reaction with the ambient atmosphere. Another such situation occurs when an "inverted" cell structure is considered, i.e., first the Li anode is formed, followed by the electrolyte and cathode. This structure can be vacuum deposited or formed by non-vacuum methods (slot die, printing, etc.). In the case of an inverted battery structure, a challenge arises when an electrolyte layer such as LiPON needs to be deposited on the Li metal surface.

  Clearly, there is a need for electrochemical device structures, deposition processes, and manufacturing equipment that can accommodate the deposition of LiPON dielectric thin films on lithium metal surfaces.

The present disclosure includes a method of depositing a solid electrolyte layer, such as LiPON, an electrolyte material used in high energy density solid state batteries on lithium metal. To avoid contact of the nitrogen plasma with lithium metal during LiPON deposition, first, using a Li ₃ PO ₄ target, the ion conductivity is lower but still very thin (10 nm˜ A 100 nm) Li ₃ PO ₄ layer is deposited on the lithium metal in a 100% Ar atmosphere. Then, following the deposition of Li ₃ PO ₄ film, nitrogen plasma treatment is performed to improve the ionic conductivity of Li ₃ PO ₄ film, then, LiPON deposition, optionally in a pure nitrogen atmosphere by the same target Done to a thickness of.
According to some embodiments of the present disclosure, a method of manufacturing an electrochemical device comprising a lithium metal electrode includes providing a substrate having a lithium metal electrode on a surface, and a first dielectric on the lithium metal electrode. After depositing the first dielectric material layer and depositing the first dielectric material layer, the steps of depositing the material layer, which is sputtering Li ₃ PO ₄ in an argon environment. Inducing and maintaining a nitrogen plasma over the first dielectric material layer, providing ion bombardment of the first dielectric material layer to mix nitrogen therein; And depositing a second dielectric material layer on the ion-bombarded first dielectric material layer after the deposition step, the induction step, and the maintenance step. Te is to sputter a Li ₃ PO ₄ in a nitrogen-containing environment may include a step of depositing a second dielectric material layer.

According to a further embodiment of the present disclosure, an electrochemical device comprises a substrate having a lithium metal electrode on a surface and an ion bombarded first dielectric material layer on the lithium metal electrode, wherein the electrochemical device is in an argon environment. A first dielectric material layer subjected to ion bombardment, which is a material layer formed by sputtering a Li ₃ PO ₄ target and subsequently performing plasma treatment in a nitrogen-containing environment, and a first ion-bombarded first dielectric material layer. A second dielectric material layer overlying the first dielectric material layer, the second dielectric material layer being formed by sputtering Li ₃ PO ₄ in a nitrogen-containing environment, and a second dielectric material A second electrode on the layer.
Furthermore, the present disclosure provides tools configured to perform the methods of the present disclosure described herein.
These and other aspects and features of the present disclosure will become apparent to those of ordinary skill in the art by reading the following description of specific embodiments of the present disclosure in conjunction with the accompanying figures.

It is a cross-sectional view of a conventional thin film battery. 1 is a schematic diagram of a deposition system according to some embodiments of the present disclosure. FIG. 2 is a flow diagram for deposition of a solid electrolyte and barrier layer thin film on a lithium metal electrode of an electrochemical device according to some embodiments of the present disclosure. 1 is a cross-sectional view of a vertically stacked thin film battery according to some embodiments of the present disclosure. FIG. 1 is a schematic diagram of a thin film deposition cluster tool according to some embodiments of the present disclosure. FIG. 1 is a diagram of a thin film deposition system having multiple in-line tools according to some embodiments of the present disclosure. FIG. FIG. 3 is an illustration of an in-line deposition tool according to some embodiments of the present disclosure.

  Embodiments of the present disclosure will now be described in detail with reference to the drawings provided as an illustration of the present disclosure to enable those skilled in the art to practice the present disclosure. The drawings provided herein include diagrams of devices and device process flows, which are not drawn to scale. In particular, the following figures and examples are not meant to limit the scope of the disclosure to a single embodiment, and other embodiments are possible by replacing some or all of the elements described or illustrated. It is. Further, if well-known components can be used to partially or fully implement certain elements of the present disclosure, the disclosure of such well-known components is not intended to obscure the present disclosure. Only the parts necessary for understanding are described, and detailed descriptions of other parts of such well-known components are omitted. As used herein, an embodiment showing a singular component is not to be considered limiting, and unless otherwise specified herein, the present disclosure includes other embodiments that include a plurality of the same component. It is intended to be included and vice versa. Moreover, applicants do not intend for any term in the present specification or claims to be considered to have an uncommon or special meaning unless explicitly stated as such. Further, this disclosure includes present and future known equivalents to the well-known components cited herein by way of example.

In various electrochemical devices including TFB, deposition of a LiPON layer on a lithium metal surface is desirable. The conventional method used to deposit LiPON is physical vapor deposition (PVD) radio frequency (RF) sputtering of a Li ₃ PO ₄ target in a nitrogen environment. The problem is that after the substrate (lithium metal) comes into contact with the nitrogen plasma and before the LiPON covers the substrate, the sputtering of the nitrogen plasma
It is to cause a reaction of 6Li + N ₂ → 2Li ₃ N. The product L ₃ N has a very small voltage range (about 0.4 V) relative to the Li reference electrode. The formation of Li ₃ N in the substrate is not a problem (Li ₃ N is a Li ion conductor), but we have found that this reaction is not self-regulating and is a lithium metal that is a charge carrier for the battery. It has been discovered that only charge carriers for battery operation remain in the cathode. Here, the inventors assume that the cathode is deposited in a lithiated full discharge state, and the circulating carrier is extracted therefrom. Such cells without additional Li-ion charge carrier reservoirs are typically lower because the loss of charge carrier Li by various mechanisms directly affects capacity and cycle life over the life of the battery. Shows cycling and capacity retention. Therefore, a viable method of depositing LiPON on lithium metal is important in manufacturing high performance functional batteries of the type described above.

  Forming such a stable stack comprising LiPON material deposited on Li is also inherently complex, such as by using a very thick cathode layer deposited with non-vacuum with electrolyte. It provides an opportunity to make a cell stack, which can result in higher capacity, higher energy density, and lower cost. Lower costs can be obtained from the non-vacuum method of forming a thick cathode. For example, a “laminated dual substrate structure” where one side is substrate / ACC / Li / barrier layer / LiPON and the other side is substrate / CCC / cathode / electrolyte.

A thin Li ₃ PO ₄ barrier layer sputtered with only Ar effectively prevents lithium metal from contacting the nitrogen plasma during the subsequent steps of forming the LiPON. This effectively avoids the reaction between the lithium metal and nitrogen plasma described above when the LiPON layer is actually deposited. In addition, the entire process can be performed continuously in the same sputtering chamber, without air shut-off, without solution processing, and thus without additional costs. For single wafers, a batch processing tool such as Applied Materials Endura ™ can be used. In an “in-line” tool where the substrate moves continuously in front of multiple adjacent targets, the first target can be used as an initial barrier coating step, with the remainder of the later targets accumulating the necessary LiPON layer. Can also be used, and this is also done within a single tool. In order to compensate for the lower ionic conductivity of the initial barrier layer, a nitrogen plasma treatment is incorporated after the Li ₃ PO ₄ layer is first deposited. This not only increases ionic conductivity, but also allows better protection during the subsequent LiPON deposition step due to the pinhole repair effect of the plasma treatment. Obviously, there are multiple ways to treat the layer with plasma after Li ₃ PO ₄ deposition in an Ar environment has been performed. Note that Ar plasma can provide pinhole repair, and nitrogen plasma can provide both ionic conductivity and pinhole repair. Thus, sputtering can be performed using Ar plasma, and the subsequently sputtered film can be treated with nitrogen plasma.

FIG. 2 shows a schematic diagram of an example of a deposition tool 200 configured for a deposition method according to the present disclosure. The deposition tool 200 includes a vacuum chamber 201, a sputter target 202, a substrate 204, and a substrate pedestal 205. In the case of LiPON deposition, the target 202 can be Li ₃ PO ₄ and a suitable substrate 204 is silicon, silicon nitride on Si, glass, PET (polyethylene terephthalate), mica, metal foil such as copper, etc. If necessary, current collector and electrode layers are already deposited and patterned. See, for example, FIG. 1 and FIG. The chamber 201 has a vacuum pump system 206 and a process gas supply system 207. A plurality of power supplies are connected to the target. Each target power source has a matching network for processing a radio frequency (RF) power source. A filter is used to allow the use of two power supplies operating at different frequencies, and the filter acts to protect target power supplies operating at lower frequencies from damage due to higher frequencies. Similarly, a plurality of power supplies are connected to the substrate. Each power source connected to the substrate has a matching network for processing a radio frequency (RF) power source. In order to allow the use of two power supplies operating at different frequencies, a filter is used, which acts to protect the power supply connected to the substrate operating at a lower frequency from damage due to higher frequencies. .

＊１ＭＨｚ未満の周波数を使用することができる。 Depending on the type of deposition and plasma pinhole reduction technique used, one or more of the power sources connected to the substrate can be a DC source, a pulsed DC (pDC) source, an RF source, and the like. Similarly, one or more of the target power sources can be a DC source, a pDC source, an RF source, and the like. Some examples of the configuration and use of these power supplies (PS) are provided in Table 1 below. Further, the concept and configuration of the combined power supply is described in Kwak et al., US Patent Application Publication No. 2009/0288843, which is hereby incorporated by reference in its entirety, and some embodiments of the present disclosure. Can be used for thin film deposition. For example, combinations of power sources other than RF sources may be effective to provide reduced pinhole density in the deposited film. In addition, the substrate can be heated during deposition.

* A frequency less than 1 MHz can be used.

Table 1 provides an exemplary configuration of a power supply for a sputter deposition and plasma pinhole filling process according to some embodiments of the present disclosure. Sputter deposition # 1 and # 2 can be used to sputter deposit materials such as LiPON or Li ₃ PO ₄ using a Li ₃ PO ₄ target in a nitrogen or argon environment (for argon environments). Subsequent nitrogen plasma treatment, which can also be part of the pinhole filling process, can be used to mix the nitrogen needed to improve the ionic conductivity of Li ₃ PO ₄ lithium ions).

According to some embodiments of the present disclosure, LiPON deposition on a Li metal electrode can proceed according to the schematic process flow of FIG. The process flow includes providing a substrate with a lithium metal anode (310), depositing a thin Li ₃ PO ₄ dielectric layer on the lithium metal anode (320), and inducing a nitrogen-containing plasma over the substrate. And maintaining an ion bombardment of the deposited dielectric layer to modify the composition of the dielectric (mixing nitrogen to improve Li ⁺ ion conductivity) (330); on ₃ PO ₄ dielectric may include a step (340) depositing a LiPON layer. As used herein, a thin dielectric layer refers to a Li ₃ PO ₄ dielectric layer having a thickness of a few nanometers to hundreds of nanometers, in embodiments a layer having a thickness of 10 nm to 100 nm, and in a further embodiment a thickness. Refers to a layer of 20 nm to 60 nm.

More generally, according to embodiments of the present disclosure, the following method can be used to make an electrochemical device having a lithium metal electrode. First, a substrate having a lithium metal electrode thereon is provided. The substrate can be glass, silicon, copper or the like. Second, a first dielectric material layer is deposited on the lithium metal electrode by sputtering Li ₃ PO ₄ in an argon environment. Third, the RF target power is turned off and the chamber gas is changed to provide a nitrogen-containing environment, or the substrate is moved to a different chamber having a nitrogen-containing environment. Fourth, RF is directly applied to the substrate using an RF substrate power supply to generate a local plasma adjacent to the substrate surface. This plasma produces high energy ions with sufficient energy to allow the Li ⁺ ion conductivity to be improved by mixing nitrogen into the first layer. Fifth, the plasma treatment is terminated, and then a second dielectric material layer is deposited over the ion bombarded first layer by sputter deposition from a Li ₃ PO ₄ source in a nitrogen environment. Note that the nitrogen plasma treatment of the first layer can also be effective in removing any pinholes that may have been formed in the first layer. Furthermore, the nitrogen plasma treatment can be performed in a separate chamber from the deposition of the first layer, and further, the second layer deposition can be performed in the same chamber as the nitrogen plasma treatment, but in a different chamber. Note that this may be done at

The inventors have found that the deposition of thin films by sputtering a Li ₃ PO ₄ target with argon compared to the deposition of thin films using sputter deposition from a Li ₃ PO ₄ target in a nitrogen environment. I noticed that it also seems to improve the effectiveness of pinhole reduction. This is because nitrogen impairs the action of the Li ₃ PO ₄ target, which can result in particle generation by the target and these particles can cause pinholes in the deposited film. On the other hand, argon does not impair the action of the target and can therefore be for reducing particle shedding and pinhole formation. In addition, films formed by sputtering Li ₃ PO ₄ using an argon environment and then treated with nitrogen plasma for pinhole removal were sputter deposited using the nitrogen environment but with nitrogen plasma. Compared to the film without post-deposition treatment, it showed improved ionic conductivity. The improved ionic conductivity may be due to a more effective mixing of nitrogen into the LiPON film during nitrogen plasma treatment. A LiPON material with a nitrogen mixture can be represented by Li _a PO _b N _c , where 2.5 ≦ a ≦ 3.5, 3.7 ≦ b ≦ 4.2, and 0.05 ≦ c ≦ 0.3. To a certain extent, the higher the nitrogen content, the higher the ionic conductivity. Note that the efficiency of the nitrogen plasma process for pinhole removal and improved ionic conductivity can be increased by controlling the substrate temperature. For LiPON deposition, higher temperatures improve nitrogen mixing, but the temperature should not be too high, otherwise the film may crystallize. Controlling the substrate temperature to a temperature in the range of room temperature to 300 ° C. can provide a more efficient process for LiPON thin film deposition. In addition, it is expected that similar results can be obtained using other gases such as xenon instead of argon, but the use of gas is limited due to the higher cost of gases such as xenon compared to argon. Sometimes.

†電力の上限は、使用される電源の限界によるものであり、ターゲット面積によって決定されるプロセスに対する上限およびターゲット材料の電力密度の限界を表すものではない。電力は、ターゲットの亀裂が始まる点まで増大させることができることが予期される。 Table 2 below shows a sample for Li ₃ PO ₄ deposition and nitrogen plasma treatment according to some embodiments of the present disclosure performed in an Applied Materials 200 mm Endura ™ standard physical vapor deposition (PVD) chamber. The plasma strategy is shown.

† The upper limit of power is due to the limit of the power source used, and does not represent the upper limit for the process determined by the target area and the limit of power density of the target material. It is expected that the power can be increased to the point where the target crack begins.

Table 2 provides an example of process conditions for sputtering Li ₃ PO ₄ to form a thin film followed by plasma treatment to improve Li ⁺ ion conductivity and reduce pinhole density. . This is just one example of the many different process conditions that can be used. Note that this process is tailored for larger area tools. For example, an inline tool with a 1400 mm × 190 mm square Li ₃ PO ₄ target is operated at 10 kW. Large in-line targets can operate at RF power with an upper limit determined by the target area and a power density limit of the target material.

Furthermore, the process conditions can be varied from the above conditions. For example, the deposition temperature can be higher, the source power can be pDC, and the sputtering gas can be an Ar / N ₂ mixture. After reading this disclosure, those skilled in the art will appreciate that adjustments to these parameters can be made if desired to improve the uniformity, surface roughness, layer density, etc. of the deposited film. .

  FIG. 4 shows an example of an electrochemical device having a vertical stack manufactured by the method of the present disclosure. Although the method of the present disclosure can also be used to manufacture a device having the schematic configuration of FIG. 1, the present disclosure includes a barrier layer between the lithium metal anode and the LiPON electrolyte. In FIG. 4, the vertical stack includes a substrate 410, a lithium metal anode 420, a barrier layer 430, an electrolyte layer 440, and a cathode layer 450. It can also comprise a current collector for the anode and / or cathode, a protective coating covering the entire stack, and electrical contacts for the anode and cathode (not shown).

  Although FIG. 2 shows a chamber configuration with a horizontal plane target and substrate, the target and substrate can also be held in a vertical plane. This configuration can help alleviate particle problems when the target itself produces particles. Furthermore, the position of the target and the substrate can be interchanged so that the substrate is held above the target. Furthermore, the substrate can be flexible and can be moved in front of the target by an open reel system, the target can be a rotating cylindrical target, and the target is non-planar And / or the substrate can be non-planar.

FIG. 5 is a schematic diagram of a processing system 600 for manufacturing a TFB device according to some embodiments of the present disclosure. The processing system 600 includes a standard mechanical interface (SMIF) 610 to a cluster tool 620 that includes a reactive plasma cleaning (RPC) chamber 630 and process chambers C1-C4 (641-644). The process chambers C1 to C4 can be used in the above process steps. If necessary, the glove box 650 can also be attached to the cluster tool. The glove box can store the substrate in an inert environment (eg, under a noble gas such as He, Ne, or Ar), which is useful after the alkali metal / alkaline earth metal deposition. . If necessary, a pre-combustion chamber 660 to the glove box can also be used. The pre-combustion chamber is a gas exchange chamber (inert gas to air and vice versa) that allows substrates to be taken in and out of the glove box without contaminating the inert environment within the glove box ( (Note that the glove box can also be replaced by a drying room environment with a sufficiently low dew point, such as that used by lithium foil manufacturers). Chambers C1-C4 can be configured for process steps for manufacturing thin film battery devices, which include, as described above, deposition of a Li metal layer on a substrate, a barrier layer of Li ₃ PO ₄ , Subsequent nitrogen plasma treatment can then include the deposition of an electrolyte layer (eg, LiPON by RF sputtering a Li ₃ PO ₄ target in N ₂ ). Although a cluster arrangement for the processing system 600 has been shown, a linear system can also be utilized, where the processing chambers are arranged in a row and do not have a transfer chamber, so the substrate is one chamber. It should be understood that it moves continuously from one to the next chamber.

  FIG. 6 shows a diagram of an in-line manufacturing system 700 having a plurality of in-line tools 710, 720, 730, 740, etc., according to some embodiments of the present disclosure. In-line tools can include tools that deposit all layers of an electrochemical device including, for example, TFB. Further, the inline tool can include pre- and post-conditioning chambers. For example, the tool 710 may be a pump down chamber that establishes a vacuum before the substrate enters the deposition tool 720 through the vacuum airlock 715. Some or all of the inline tools can be vacuum tools separated by a vacuum airlock 715. Note that the order of process tools and specific process tools within a process line is determined by the particular electrochemical device manufacturing method being used. For example, one or more of the in-line tools are dedicated to depositing a buffer layer on Li metal, including nitrogen plasma treatment for improved ionic conductivity, as described above, according to some embodiments of the present disclosure. It can be. Further, the substrate can be moved through an in-line manufacturing system that is oriented horizontally or vertically. Furthermore, the inline system can be adapted for open reel processing of web substrates.

  To illustrate substrate movement through an in-line manufacturing system such as that shown in FIG. 6, a substrate conveyor 750 having only one in-line tool 710 in place is shown in FIG. As shown, a substrate holder 755 (showing a partially cut away substrate holder so that the substrate can be seen) containing the substrate 810 is a conveyor 750 for moving the holder and substrate through the inline tool 710 or Mounted on equivalent device. A suitable inline platform for a processing tool 710 having a vertical substrate configuration is New Materials ™ from Applied Materials. A suitable inline platform for a processing tool 710 having a horizontal substrate configuration is Applied Materials' Aton ™. Furthermore, the in-line process can also be performed on an open reel system such as Applied Materials' SmartWeb ™.

An apparatus for manufacturing an electrochemical device comprising a lithium metal electrode according to an embodiment of the present disclosure is a first system for depositing a first dielectric material layer on a lithium metal electrode on a substrate, the first dielectric In a first system where the deposition of the body material layer is to sputter Li ₃ PO ₄ in an argon environment and in a second system that induces and maintains a nitrogen plasma over the first dielectric material layer A second system for providing ion bombardment of the first dielectric material layer and mixing nitrogen therein; and a second dielectric material on the ion bombarded first dielectric material layer A third system for depositing layers, wherein the deposition of the second dielectric material layer is to sputter Li ₃ PO ₄ in a nitrogen-containing environment. The first, second and third systems can be the same system. In an embodiment, the second and third systems are the same system. The device can be a cluster tool or an inline tool. Furthermore, in an in-line or open-reel device, the deposition and induction steps can be performed in separate adjacent systems.

  The present disclosure can be used in any application field having LiPON deposition on a lithium metal surface, such as, for example, energy storage devices, electrochromic devices.

  Although the present disclosure has been specifically described with reference to specific embodiments of the present disclosure, those skilled in the art will recognize that changes and modifications can be made in form and detail without departing from the spirit and scope of the disclosure. It will be readily apparent.

Claims (15)

A method of manufacturing an electrochemical device comprising a lithium metal electrode, comprising:
Providing a substrate having a lithium metal electrode on the surface;
Depositing a first dielectric material layer on the lithium metal electrode, the depositing the first dielectric material layer being sputtering Li ₃ PO ₄ in an argon environment;
After the step of depositing the first dielectric material layer, inducing and maintaining a nitrogen plasma on the first dielectric material layer, the ion bombardment of the first dielectric material layer Providing and inducing and maintaining nitrogen mixed therein; and
Depositing a second dielectric material layer on the ion-bombarded first dielectric material layer after the deposition step, the induction step, and the maintaining step, wherein the Li _{3 in} a nitrogen-containing environment; Depositing said second dielectric material layer, which is sputtering PO ₄ .   The method of claim 1, wherein the first dielectric material layer has a thickness of 10 nm to 100 nm.   The method of claim 1, wherein the first dielectric material layer has a thickness of 40 nm to 60 nm.   The method of claim 1, wherein the step of depositing a first dielectric material layer is performed in a first vacuum chamber and the step of inducing and maintaining is performed in a second vacuum chamber. The composition of the first dielectric material layer subjected to ion bombardment is represented by the formula Li _a PO _b N _c , where 2.5 ≦ a ≦ 3.5, 3.7 ≦ b ≦ 4.2, And the method of claim 1, wherein 0.05 ≦ c ≦ 0.3.   The method of claim 1, wherein the step of inducing and maintaining increases an ionic conductivity of lithium ions in the first dielectric material layer.   The method of claim 1, wherein the step of inducing and maintaining reduces the density of pinholes in the first dielectric material layer.   The method of claim 1, wherein the substrate is heated during the step of inducing and maintaining. The method of claim 1, wherein the step of depositing the second dielectric material layer comprises sputtering Li ₃ PO ₄ in a nitrogen and argon environment.   The method of claim 1, wherein the second dielectric material layer has a composition represented by the formula LiPON. A substrate having a lithium metal electrode on the surface;
A first dielectric material layer bombarded with ions on the lithium metal electrode, formed by sputtering a Li ₃ PO ₄ target in an argon environment followed by a plasma treatment in a nitrogen-containing environment. A first dielectric material layer subjected to ion bombardment,
A second dielectric material layer overlying the ion-bombarded first dielectric material layer, the second dielectric material layer being formed by sputtering Li ₃ PO ₄ in a nitrogen-containing environment; ,
An electrochemical device comprising: a second electrode on the second dielectric material layer. The first dielectric material layer subjected to ion bombardment has a composition represented by the formula Li _a PO _b N _c , where 2.5 ≦ a ≦ 3.5, 3.7 ≦ b ≦ 4. The electrochemical device of claim 11, wherein .2 and 0.05 ≦ c ≦ 0.3.   The electrochemical device of claim 11, wherein the second dielectric material layer has a composition represented by the formula LiPON.   The electrochemical device according to claim 11, wherein the electrochemical device is a thin film battery. An apparatus for producing an electrochemical device comprising a lithium metal electrode,
A first system for depositing a first dielectric material layer on a lithium metal electrode on a substrate, wherein the depositing the first dielectric material layer comprises Li ₃ PO ₄ in an argon environment. A first system that is sputtering;
A second system for inducing and maintaining a nitrogen plasma over the first dielectric material layer, the second system providing ion bombardment of the first dielectric material layer to mix nitrogen therein; Two systems,
A third system for depositing a second dielectric material layer on the ion bombarded first dielectric material layer, wherein the depositing the second dielectric material layer comprises a nitrogen-containing environment. An apparatus comprising a third system in which Li ₃ PO ₄ is sputtered.

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