JPH1158730A - Ink jet type recording head and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a residual stress of a tin film by interposing a boron diffused membrane between a silicon single crystal substrate and a piezoelectric membrane in an ink jet type recording head for discharging ink by pressure generated by a deflected deformation of a pressure generating membrane. SOLUTION: A layer 32 in which boron to become an electric membrane is diffused is formed on an upper surface of a silicon single crystal substrate. Then, platinum to become a lower driving electrode 10 is formed as a membrane on an upper surface of the boron diffused membrane 32. A precursor of a piezoelectric film is laminated on the electrode 10, and heated to be crystallized as a piezoelectric membrane 11. Thereafter, an upper driving electrode film 12, lower driving electrode 10 and an ink chamber such as an ink chamber or the like are formed. As a result, a static deflection amount of a pressure generating membrane at the time of applying no voltage after a pressurizing camber is formed is increased form the substrate due to that the platinum of the electrode 10 loses a restraint of a tensile stress and a compressive stress of a silicon dioxide membrane from the substrate to be largely deflected if the membrane 31 does not exist. Reversely, with this constitution, since compressive stress of the silicon of the boron diffusion is weak, it is reduced to about 10 nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ink jet recording head for use in an ink jet recording apparatus for obtaining a visible image by selectively flying and fixing ink droplets on recording paper in accordance with input print data. .

More specifically, the present invention relates to an on-demand type ink jet recording head in which a nozzle plate and an ink pressurizing chamber substrate are laminated and a piezoelectric film formed on the surface of the ink pressurizing chamber substrate is pressurized by bending deformation to fly ink droplets. .

[0003]

2. Description of the Related Art As a prior art relating to the present invention, there is JP-A-5-504740.

In this conventional example, a piezoelectric film is integrally formed on a base material containing an ink pressurizing chamber by a so-called thin-film manufacturing method such as sputtering or a sol-gel method, so that a high-performance on-demand ink jet recording with a simple structure is realized. The head has been realized. In particular, a high-precision ink pressurizing chamber can be formed by performing anisotropic etching using a silicon single crystal substrate as a base material.

FIG. 8 is a cross-sectional view in the arrangement direction of an actuator such as a conventional inkjet head using a thin film PZT and a silicon single crystal substrate. 20 is a silicon single crystal substrate, 2 is a pressure chamber formed on the silicon single crystal substrate by anisotropic etching, 18 is a partition partitioning the pressure chamber, 21 is a silicon dioxide film, 10 is a lower drive electrode, 11 is a piezoelectric thin film, 12
Denotes an upper drive electrode, and each thin film has a thickness of several hundred nm to several μm. Reference numeral 30 denotes a piezoelectric strain generating unit, and reference numeral 31 denotes a support unit that supports the piezoelectric strain generating unit via a partition.

[0006]

When thin films are formed on one surface of a silicon single crystal substrate as shown in FIG. 8, residual stress is generated in these thin films. Generally, when metal thin films for electrodes 10 and 12 are formed by a sputtering film forming method or the like, a tensile stress is generated. When the silicon dioxide film 21 is formed by thermal oxidation, a compressive stress is generated. This residual stress is restrained by the silicon single crystal substrate 20, but when the pressurizing chamber 2 is formed thereafter, these stresses are released, and the piezoelectric strain generating section 30
And the support portion 31 is deformed.

The above-mentioned deformation is reduced if the tensile stress and the compressive stress of each thin film are offset, but the deformation is large if the compressive stress is superior. If the initial deformation is large, the piezoelectric strain is not efficiently converted into deflection, which is one of the factors that lowers the displacement efficiency. Further, since the support portion 31 is thinner and narrower than the piezoelectric strain generating portion, the deformation is large. If this deformation is large,
In some cases, the support portion was broken when the above-mentioned pressurized chamber was formed or during use. In particular, in order to increase the amount of deformation due to piezoelectric strain, it is desirable to make the support portion 31 thinner to lower the bending rigidity. However, such an improvement is difficult to implement because the above-mentioned adverse effects are promoted.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to propose a means for reducing the manufacturing defect and improving the reliability while increasing the actuator displacement efficiency. An object of the present invention is to provide a high-performance ink jet recording head.

[0009]

An ink jet recording head according to the present invention has ink pressurizing chambers arranged in a row on a silicon single crystal substrate via partition walls, and covers one side of the pressurizing chambers and is suspended by the partition walls. An elastic film, a lower drive electrode film, a piezoelectric film, and an upper drive electrode film, which are fixed and arranged as if forming one wall surface of the pressurizing chamber, and an ink discharge nozzle communicating with each pressurizing chamber. An ink jet recording head configured to discharge ink by a pressure generated by bending deformation of the pressure generating film, wherein the elastic film includes at least boron-diffused silicon and a lower drive electrode. It is a feature to do.

[0010] Alternatively, an ink pressurizing chamber arranged in a row on a silicon single crystal substrate via a partition, covers one side of the pressurizing chamber, and is suspended and fixed by the partition. The pressure generating film is composed of an elastic film, a lower drive electrode film, a piezoelectric film, and an upper drive electrode film, which are arranged like a pressurized film, and ink discharge nozzles communicating with the respective pressure chambers. An ink jet recording head that ejects ink by a pressure generated in the pressure generating film, wherein the pressure generating film includes a piezoelectric strain generating unit and a support unit that supports the piezoelectric strain generating unit, and the piezoelectric strain generating unit includes an upper driving electrode and It is characterized by comprising a piezoelectric film, a lower drive electrode and a silicon film in which boron is diffused.

The method of manufacturing an ink jet recording head according to the present invention comprises the steps of thermally diffusing boron on one surface of a silicon single crystal substrate and then thermally oxidizing both surfaces of the substrate. The lower drive electrode film, the piezoelectric film, and the upper drive electrode film are sequentially laminated on the silicon single crystal substrate, and a process of forming a pressure generating film for etching the electrode film and the piezoelectric film into a desired shape is performed. The method is characterized by comprising the step of forming the pressure chamber by etching.

Alternatively, after thermally oxidizing both surfaces of the silicon single crystal substrate, the silicon dioxide film on one surface of the substrate is removed,
The lower surface of the drive electrode film, the piezoelectric film, and the upper drive electrode film are sequentially laminated on the upper surface, and a pressure generating film for etching the electrode film and the piezoelectric film into a desired shape is formed. The forming step includes a step of forming the pressure chamber in the silicon single crystal substrate by anisotropic etching.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on one embodiment.

(Embodiment 1) The structure of an ink jet recording head of the present invention will be described with reference to FIGS.

FIG. 1 is a schematic perspective view of an ink jet recording head according to an embodiment of the present invention.

Reference numeral 1 denotes an ink pressurizing chamber substrate, pressurizing chambers 2 arranged in two rows in a zigzag pattern, and ink (not shown) is provided in each pressurizing chamber.
And a supply path 9 that communicates each pressurizing chamber 2 with the common flow path 3. Array pitch is 180
1 inch, about 141 microns, 64 per row
The elements are arranged to realize a print head having a printing density of 360 dots / inch and 128 nozzles in two rows.
Reference numeral 8 denotes a wiring board for supplying a signal to the displacement element.

Reference numeral 6 denotes a nozzle plate provided with a plurality of ink discharge nozzles 7 corresponding to the pressure chamber 2. After the pressure chamber substrate 1 and the nozzle plate 6 are bonded, they are fitted to the base 90 to form an ink jet recording head.

FIG. 2 is a cross-sectional view taken along the dashed line AA ′ of FIG. 1 in the direction in which the pressure chambers are arranged. The elastic film 4 on the lower surface of the pressure chamber substrate 1 is a substantially rectangular pressure generating film 50. , Lower drive electrode 1
0, a piezoelectric film 11, and an upper drive electrode 12 are sequentially laminated,
The pressure chamber substrate 1 and the pressure generating film 50 are integrally formed. The chain line 19 is one ejection element unit. In this example, the function of the elastic film 4 is also provided by giving the lower drive electrode 10 a thickness.

Reference numeral 7 denotes a nozzle in the nozzle plate 6, 13 denotes ink in the arranged pressure chambers 2, 4 denotes an elastic film, 10 denotes a lower drive electrode, 11 denotes a piezoelectric film, and 12 denotes an upper drive electrode. The piezoelectric film 11 corresponds to each pressure chamber, and is formed by etching to have a width slightly smaller than the width of the pressure chamber.

In this embodiment, the pitch of the pressurizing chamber was 141 μm, the width of the pressurizing chamber was 50 μm, the length (in the depth direction in the figure) was 1.2 mm, and the width of the partition wall was 91 μm.

Here, the principle of ink ejection will be briefly described. During standby, the switch 17a is opened to prepare for the next ejection. The standby state is shown in the ejection element at the left end of FIG. At the time of ejection, as shown in the ejection element diagram in the center of FIG. 2, the switch 17b is closed, and the same polarity as the polarization direction of the piezoelectric film 11 indicated by the arrow B is applied.
In other words, when a voltage is applied in the same manner as the applied voltage polarity during polarization, the piezoelectric film 11 expands in the thickness direction and contracts in the width direction (the horizontal direction in FIG. 2). Due to this contraction, a compressive shear stress acts on the interface between the piezoelectric film 11 and the elastic film 4, and the elastic film 4 and the piezoelectric film 11 bend upward in the drawing. Due to this deflection, the volume of the pressurizing chamber 2 is reduced, and ink droplets fly out of the nozzle. Thereafter, as shown in the right end of FIG. 2, when the switch 17c is opened again, the bent elastic film 4 and the like are restored,
The ink is filled from an ink supply path (not shown) due to the expansion of the pressure chamber volume.

The method of manufacturing the ink jet recording head according to the present invention will be described with reference to FIGS. In this example, a silicon single crystal substrate 20 which is a pressure chamber substrate having a (110) plane having a diameter of 100 mm and a thickness of 220 μm is used, and FIG.
Then, an etching protection layer 21 made of silicon dioxide is formed to a thickness of 1 μm on the entire surface by a thermal oxidation method.

Next, as shown in FIG. 3 (II), the etching protection layer 21 on one side is removed with buffered hydrofluoric acid or the like.

Thereafter, as shown in FIG. 3 (III), a layer 32 in which boron is diffused to form an elastic film later is formed on the surface from which the etching protection layer 21 has been removed in the previous step. Specifically, it can be formed by allowing a boron substrate to face a silicon single crystal substrate and leaving it in a furnace heated to 1200 ° C. for 1 to 5 hours. In this example, the film thickness was 1 μm. As a result of various experimental studies, the boron diffusion concentration is preferably from 12 to 10 residues per square cm to 16 to 10 residues, more preferably 10 to 1 residue.
The 15 remainder from 3 to 10 was optimal. If the amount is less than the lower limit, during the subsequent anisotropic etching of silicon, the erosion of the boron diffusion film by the etchant becomes severe, and the function as an etch stopper is insufficient. It did not meet the purpose of the invention.

Next, platinum to be the lower drive electrode 10 is formed to a thickness of 400 nm on the upper surface of the boron diffusion film 32 by a thin film forming method such as a sputtering film forming method. At this time, in order to increase the adhesion between the platinum layer and the upper and lower layers, ultra-thin titanium, chromium or the like may be interposed as an intermediate layer. The lower drive electrode may be made of another conductive material such as iridium as long as it has heat resistance to the subsequent heating temperature. The lower drive electrode 10
Also serves as an elastic film in combination with the boron diffusion film 32.

The precursor 24 of the piezoelectric film is laminated thereon. In this example, a precursor of a PZT-based piezoelectric film in which the molar mixing ratio of lead titanate and lead zirconate is 55% and 45% is applied eight times by a sol-gel method until a final thickness of 0.9 μm is obtained. Process / drying / degreasing was repeated to form a film. As a result of various trial experiments, the chemical formula of this piezoelectric film was PbCTiAZrBO
₃ [A + B = 1], wherein A and C in the above chemical formula are
If the selection was made in the range of 0.5 ≦ A ≦ 0.6 and 0.85 ≦ C ≦ 1.10. Piezoelectricity that could withstand practical use could be obtained. The film formation method is not limited to this method, and high-frequency sputtering film formation and CV
D or the like may be used (FIG. 3 (IV)).

Next, the entire substrate is heated for crystallization of the piezoelectric film precursor. In the present example, the piezoelectric film was crystallized by heating at 700 ° C. for 5 minutes in an oxygen atmosphere from both surfaces of the substrate using an infrared radiation light source 29 and naturally lowering the temperature.
By this process, the piezoelectric film precursor 24 was crystallized and sintered with the above-described target composition to form the piezoelectric film 11 (FIG. 3).
(V)).

Thereafter, an upper drive electrode film 12 is formed on the piezoelectric film 11. In this example, the upper drive electrode 12 is 100 nm
Thick platinum was formed by a sputter deposition method (FIG. 4 (I)).

Next, after the upper drive electrode 12 and the piezoelectric film 11 are provided with an appropriate etching mask (not shown) in accordance with the position where the pressure chamber 2 is formed, ion milling is performed in a predetermined separation shape. At the same time (FIG. 4 (II)).

Next, the lower drive electrode 10 is similarly formed with an appropriate etching mask (not shown), and is formed in a predetermined shape (connection terminal to an external drive circuit, etc.) by ion milling (FIG. 4 ( III)).

After forming a protective film (not shown for simplicity) against various chemicals immersed in a later step on the side of the substrate 20 on which the piezoelectric film is formed, at least a pressurizing chamber or pressurizing chamber on the opposite surface is formed. The window 22 is formed by etching the etching protection layer 21 with buffered hydrofluoric acid or the like in the region including the chamber partition (FIG. 4).
(IV)).

Thereafter, an anisotropic etching solution such as 80
The silicon single crystal substrate 20 is anisotropically etched by using an aqueous solution of potassium hydroxide having a concentration of about 17% kept at a temperature of ℃ so as to penetrate the silicon single crystal substrate 20 to the upper surface of the substrate. Since the boron diffusion film is hardly soluble in the potassium hydroxide, the thin film portion is not violated by the etching solution via the pressurizing chamber. Alternatively, an anisotropic etching method using an active gas such as a parallel plate type reactive ion etching may be used for forming the pressurized chamber. Through this process, a flow path such as an ink pressurizing chamber is formed (FIG. 4 (V)).

Comparing the amount of static deflection of the pressure generating film after the formation of the pressurized chamber when no voltage is applied, the conventional one is 100 to 2 nm.
In contrast to the sagging on the lower side in the 00 nm diagram, this example was about 10 nm. This is because the platinum of the lower drive electrode 10 of the conventional product largely deflected to the substrate side due to the loss of restraint from the substrate due to the tensile stress and the compressive stress of the silicon dioxide film,
It is considered that in the product of the present invention, the bending stress was reduced due to the low compressive stress of boron-diffused silicon. Also, in this example, cracking of the thin film in this step, which had frequently occurred before, hardly occurred.

A separate nozzle plate and the like are bonded and assembled to the pressurized chamber substrate formed by the above steps to complete the ink jet head.

When the ink jet recording head formed as described above was compared with a conventional structure having a conventional structure in terms of manufacturing yield and printing durability, the manufacturing yield was improved by 20% and the printing durability was improved by 40% over the conventional product. % Improved.

The amount of the initial deflection described above also affects the deformation efficiency of the pressure-generating film. The conventional product had a maximum deflection of 200 nm when a voltage of 20 V was applied.
A large deformation amount of 50 nm was obtained.

(Embodiment 2) A manufacturing method according to another embodiment of the present invention will be described with reference to FIGS. In addition, dimensions, manufacturing method,
Materials not described in the material are the same as those in the first embodiment.

Using a silicon single crystal substrate 20 which is a pressure chamber substrate, a boron diffusion layer 32 is formed on the upper surface thereof as shown in FIG. In this example, the boron diffusion layer was formed to have a thickness of 1500 nm.

Next, as shown in FIG. 5 (II), an etching protection layer 21 made of silicon dioxide is formed on the entire surface by a thermal oxidation method. At this time, a boron diffusion silicon dioxide film 33 is formed above the boron diffusion layer. In this example, the reaction time was controlled so that the thickness of the boron-diffused silicon dioxide film became 200 nm.

Next, the lower drive electrode 10 is formed on the surface where boron was diffused in the previous step by a thin film forming method such as a sputter film forming method.
Is formed with a thickness of 800 nm. The lower drive electrode 10 also serves as an elastic film. A piezoelectric film precursor 24 is laminated thereon. The composition and the like are the same as in the first embodiment (FIG. 5 (III)).

Next, the entire substrate is heated for crystallization of the piezoelectric film precursor. In this example, the piezoelectric film was crystallized by holding the substrate at 650 ° C. for 5 minutes in an oxygen atmosphere and then heating it at 900 ° C. for 3 minutes and allowing it to cool naturally from both sides of the substrate using the infrared radiation light source 29. By this step, the piezoelectric film precursor 24 was crystallized and sintered with the above-described target composition to form the piezoelectric film 11 (FIG. 5 (IV)).

When heating at a temperature exceeding 900 ° C. is performed as described above, if silicon or boron-diffused silicon and platinum are close to each other, they react with each other to form platinum silicide and peel off the film. With the silicon dioxide film 33 interposed therebetween, this film became a barrier and such a problem did not occur. Therefore, by using the manufacturing method / configuration as in this example, the PZT precursor could be fired at a higher temperature, the crystallization of PZT was promoted, and higher piezoelectric characteristics could be obtained.

Thereafter, an upper drive electrode film 12 is formed on the piezoelectric film 11. In this example, the upper drive electrode 12 is 200 nm
Thick gold was formed by a sputter deposition method (FIG. 6 (I)).

Next, an appropriate etching mask (not shown) is applied to the upper drive electrode 12 and the piezoelectric film 11 in accordance with the position where the pressure chamber 2 is to be formed. At the same time (FIG. 6 (II)).

Next, the lower drive electrode 10 and the boron-diffused silicon dioxide film were similarly formed with a suitable etching mask (not shown), and then formed into a predetermined shape by reactive vapor etching. At this time, at least the portion of the drive electrode 10 and the boron-diffused silicon dioxide film on the pressure chamber, which is to be a pressure generating film, had the same width as the piezoelectric film (FIG. 6 (III)).

After a protective film (not shown for simplicity) for various chemicals immersed in a later step is formed on the side of the substrate 20 on which the piezoelectric film is formed, at least a pressurizing chamber or a pressurizing chamber on the opposite surface is formed. The window 22 is formed by etching the etching protection layer 21 with hydrogen fluoride in the region including the chamber partition (FIG. 6 (I
V)).

Thereafter, an anisotropic etching solution, for example, 80
The silicon single crystal substrate 20 is anisotropically etched by using an aqueous solution of potassium hydroxide having a concentration of about 17% kept at a temperature of ° C. so as to penetrate the silicon single crystal substrate 20 to the upper surface of the substrate. The pressurized chamber may be formed by a reactive gas phase etching method using an active gas such as a parallel plate type reactive ion etching. Through this process, a flow path such as an ink pressurizing chamber is formed (FIG. 6 (V)).

When the static deflection amount of the pressure generating film after the formation of the pressurizing chamber when no voltage is applied is compared, the conventional one is 100 nm to 2 nm.
In contrast to the sagging on the lower side in the 00 nm figure, this example was about 30 nm. Also, in this example, cracking of the thin film in this step, which had frequently occurred before, hardly occurred.

A separate nozzle plate 6, an ink supply tube, and a support (not shown) are bonded to the pressurized chamber substrate formed by the above steps.

FIG. 7 shows details of the pressure generating film of this example. Incidentally, in order to increase the displacement efficiency of such a unimorph type actuator, it is preferable that the supporting portion 31 be easily bent to reduce the rigidity as compared with the piezoelectric strain generating portion 30.

In order to make the supporting portion bend easily, it is necessary to increase the area of the supporting portion or to reduce the thickness of the supporting portion. In the former case, since the width of the pressurizing chamber is limited, the area of the piezoelectric strain generating portion is relatively reduced, so that the displacement efficiency is not improved. The displacement efficiency can be increased by removing the lower drive electrode film of the support portion 31 and forming the support portion only with the boron diffusion film as in this example, and the manufacturing is easy as described above.

On the other hand, if it is attempted to form the support portion only with the conventional silicon dioxide film, the support portion 31 becomes only the silicon dioxide film, the stress cannot be canceled by the film lamination, and the deformation bending due to the release of the compressive stress causes this. Concentrates on the support, causing remarkable failure. By using a boron diffusion film as in this example, the stress release was reduced, and this failure failure could be avoided.

In this embodiment, the supporting portion 31 is formed of a boron diffusion film 32.
Although only the boron diffusion silicon dioxide film 33 is thin, if the compressive stress of the boron diffusion silicon dioxide film is so small as to be negligible, the support portion may be composed of these two layers.

By interposing a boron-diffused silicon dioxide film between the boron-diffused film and the platinum of the lower drive electrode, a compound of platinum and silicon is generated even when baking at a temperature exceeding 700 ° C. as in this example, It did not reduce the adhesion between the layers. Of course, in addition to this example, such a barrier for suppressing the reaction between platinum and silicon may be formed by separately forming a silicon dioxide film on the upper surface of the boron diffusion film by a CVD method or the like.

The production yield and printing durability of the ink jet recording head formed as described above were compared with those of the conventional structure, and the production yield was improved by 50% and the printing durability was 40% over the conventional product. % Improved. Such initial deflection also affects the deformation efficiency of the pressure-generating film, and the conventional product has a maximum deflection of 200 nm when a voltage of 20 V is applied, while the product of the present invention obtains a large deformation of 400 nm. Was completed.

In this embodiment, a PZT-based material has been described as the piezoelectric film. However, a material obtained by adding other metal oxides such as niobium oxide, nickel oxide, and magnesium oxide to this film, or a material other than the PZT-based material is used. The present invention is effective.

In this embodiment, an application example of the ink jet head has been described. However, the present invention is applicable to all other micro element devices such as micro optical devices, micro pressure detectors, etc. The present invention is effective.

[0058]

According to the present invention, by interposing a boron diffusion film between a silicon single crystal substrate and a piezoelectric film, the residual stress of the thin film is reduced, and the production yield due to the release of the residual stress is reduced. It is possible to realize a highly reliable and high performance ink jet recording head by solving the displacement characteristics and the reduction in reliability.

[Brief description of the drawings]

FIG. 1 is a perspective view of an ink jet recording head according to an embodiment of the present invention.

FIG. 2 is a sectional view of an ink jet recording head according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a manufacturing process of the ink jet recording head according to the first embodiment of the present invention.

FIG. 4 is a diagram illustrating a manufacturing process of the ink jet recording head according to the first embodiment of the present invention.

FIG. 5 is a diagram illustrating a manufacturing process of an ink jet recording head according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a manufacturing process of an ink jet recording head according to a second embodiment of the present invention.

FIG. 7 is a sectional view of an ink jet recording head according to a second embodiment of the present invention.

FIG. 8 is a diagram illustrating a problem of a conventional ink jet recording head.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pressurizing chamber substrate 2 pressurizing chamber 3 common flow path 4 elastic film 6 nozzle plate 7 ink discharging nozzle 8 wiring board 9 supply path 10 lower drive electrode 11 piezoelectric film 12 upper drive electrode 13 ink 14 drive voltage source 15 wiring Reference Signs List 16 Wiring 17 Switch 18 Pressurizing chamber partition wall 19 Ink ejection element unit 20 Silicon single crystal substrate 21 Etching protective layer 22 Etching window 24 Piezoelectric film precursor 29 Radiation light source 30 Piezoelectric strain generator 31 Support for piezoelectric strain generator 32 Boron Diffusion film 33 Boron diffusion silicon dioxide film

Claims (10)

[Claims] 1. An ink pressurizing chamber arranged in a row on a silicon single crystal substrate via a partition, covering one surface of the pressurizing chamber, suspended and fixed by the partition, and forming one wall of the pressurizing chamber. The pressure generating film is composed of an elastic film, a lower drive electrode film, a piezoelectric film, and an upper drive electrode film, which are arranged like an ink discharge nozzle communicating with each pressure chamber. An ink jet recording head for discharging ink by generated pressure, wherein the elastic film comprises at least silicon in which boron is diffused and a lower drive electrode. 2. The ink jet recording head according to claim 1, wherein said elastic film comprises at least silicon in which boron is diffused, a silicon dioxide film, and a lower drive electrode. 3. The ink jet recording head according to claim 1, wherein the elastic film comprises at least silicon in which boron is diffused, a silicon dioxide film in which boron is diffused, and a lower drive electrode. 4. An ink jet recording head according to claim 1, wherein said lower drive electrode is made of platinum. 5. An ink pressurizing chamber arranged in a row on a silicon single crystal substrate via a partition, covering one surface of the pressurizing chamber, being suspended and fixed by the partition, and forming one wall of the pressurizing chamber. The pressure generating film is composed of an elastic film, a lower drive electrode film, a piezoelectric film, and an upper drive electrode film, which are arranged like an ink discharge nozzle communicating with each pressure chamber. An ink jet recording head that discharges ink by a generated pressure, wherein the pressure generating film includes a piezoelectric strain generating unit and a support unit that supports the piezoelectric strain generating unit, and the piezoelectric strain generating unit includes an upper driving electrode and a piezoelectric driving unit. An ink jet recording head comprising a conductive film, a lower drive electrode, and a silicon film in which boron is diffused. 6. The ink jet recording head according to claim 5, wherein said support portion is made of a silicon film in which boron is diffused. 7. The semiconductor device according to claim 5, wherein said support portion is composed of a silicon film in which boron is diffused and a silicon dioxide film.
The ink jet recording head according to the above. 8. The ink jet recording head according to claim 5, wherein said support portion is composed of a silicon film in which boron is diffused and a silicon dioxide film in which boron is diffused. 9. The process of thermally diffusing boron on one surface of a silicon single crystal substrate and then thermally oxidizing both surfaces of the substrate, wherein the lower drive electrode film, the piezoelectric film, and the upper A step of forming a pressure generating film for sequentially laminating the drive electrode films and etching these electrode films and the piezoelectric film into a desired shape, and a step of forming the pressure chamber by anisotropic etching on the silicon single crystal substrate. A method for manufacturing an ink jet recording head. 10. After both surfaces of a silicon single crystal substrate are thermally oxidized, a silicon dioxide film on one surface of the substrate is removed, boron is thermally diffused on the removed surface, and a lower drive electrode film is formed on the upper surface. A step of forming a pressure generating film for sequentially laminating a piezoelectric film and an upper drive electrode film and etching the electrode film and the piezoelectric film into a desired shape; Forming an ink jet recording head.