阅读说明：本技术 一种双结型Ga2O3器件及其制备方法 (Double-junction Ga2O3Device and method of making the same ) 是由 李京波 王小周 赵艳 李翎 任家呈 于 2021-07-05 设计创作，主要内容包括：本发明公开了一种双结型Ga-(2)O-(3)器件及其制备方法,所述制备方法包括：选取柔性衬底；在柔性衬底的上表面覆盖多层BN薄膜,形成第一BN薄膜层；在第一BN薄膜层上设置Ga-(2)O-(3)衬底并加热,以使Ga-(2)O-(3)衬底与第一BN薄膜层紧密贴合；在Ga-(2)O-(3)衬底上进行离子注入,形成P型Ga-(2)O-(3)层；在P型Ga-(2)O-(3)层上进行离子注入,形成N型Ga-(2)O-(3)层；在N型Ga-(2)O-(3)层的上表面生长ZnSe荧光层；在ZnSe荧光层的上表面涂覆可见光反射层；在可见光反射层的上表面两侧分别刻蚀制作源电极和漏电极；在源电极、漏电极及可见光反射层的上表面覆盖多层BN薄膜,形成第二BN薄膜层。该双结型Ga-(2)O-(3)器件具有优秀的芯片性能,能承受更高的温度和电压,能应用在大电压、大功率的设备与场景中。(The invention discloses a double-junction Ga 2 O 3 A device and a method of making the same, the method of making comprising: selecting a flexible substrate; covering a plurality of BN thin films on the upper surface of the flexible substrate to form a first BN thin film layer; providing Ga on the first BN thin film layer 2 O 3 The substrate is heated to cause Ga 2 O 3 The substrate is tightly attached to the first BN thin film layer; in Ga 2 O 3 Performing ion implantation on the substrate to form P-type Ga 2 O 3 A layer; in P-type Ga 2 O 3 Ion implantation is performed on the layer to form an N-typeGa 2 O 3 A layer; in the N-type Ga 2 O 3 Growing a ZnSe fluorescent layer on the upper surface of the layer; coating a visible light reflecting layer on the upper surface of the ZnSe fluorescent layer; etching and manufacturing a source electrode and a drain electrode on two sides of the upper surface of the visible light reflecting layer respectively; and covering a plurality of BN thin films on the upper surfaces of the source electrode, the drain electrode and the visible light reflecting layer to form a second BN thin film layer. The double-junction Ga 2 O 3 The device has excellent chip performance, can bear higher temperature and voltage, and can be applied to equipment and scenes with large voltage and high power.)

1. Double-junction Ga₂O₃A method of making a device, comprising:

s1: selecting a flexible substrate;

s2: covering a plurality of BN thin films on the upper surface of the flexible substrate to form a first BN thin film layer;

S3: providing Ga on the first BN thin film layer₂O₃Substrate and heating to heat the Ga₂O₃The substrate is tightly attached to the first BN thin film layer;

s4: in the Ga₂O₃Performing ion implantation on the substrate to form P-type Ga₂O₃A layer;

s5: in the P-type Ga₂O₃Ion implantation is performed on the layer to form N-type Ga₂O₃Layer of the N-type Ga₂O₃The thickness of the layer is less than that of the P-type Ga₂O₃The thickness of the layer;

s6: in the N-type Ga₂O₃Growing a ZnSe fluorescent layer on the upper surface of the layer;

s7: coating a visible light reflecting layer on the upper surface of the ZnSe fluorescent layer;

s8: respectively etching and manufacturing a source electrode and a drain electrode on two sides of the upper surface of the visible light reflecting layer, so that the lower surfaces of the source electrode and the drain electrode are respectively equal to the lower surfaces of the Ga₂O₃An upper surface contact of the substrate;

s9: and covering a plurality of BN thin films on the upper surfaces of the source electrode, the drain electrode and the visible light reflecting layer to form a second BN thin film layer.

2. Double-junction Ga according to claim 1₂O₃The preparation method of the device is characterized in that the flexible substrate is a PET flexible substrate with the thickness of 1-2mm, and the Ga₂O₃The thickness of the substrate was 150-200 μm.

3. Double-junction Ga according to claim 1₂O₃The method for manufacturing a device is characterized in that, in step S3, the heating temperature is 150-200 ℃.

4. Double-junction Ga according to claim 1₂O₃Method for manufacturing a device, characterized in that the P-type Ga₂O₃The doping element of the layer is B or N element with doping concentration of 1 × 10²²-3×10²²cm^-3The thickness is 5-10 μm.

5. The double-junction Ga according to claim 4₂O₃A method for producing a device, characterized in that the N-type Ga₂O₃The doping element of the layer is P element with doping concentration of 1 × 10²³-4×10²³cm^-3The thickness is 2-5 μm.

6. Double-junction Ga according to claim 1₂O₃The preparation method of the device is characterized in that the thickness of the ZnSe fluorescent layer is 60-100nm, the material of the visible light reflecting layer is Ag, and the thickness is 10-15 mu m.

7. The double-junction Ga according to any one of claims 1 to 6₂O₃The preparation method of the device is characterized in that the first BN thin film layer and the second BN thin film layer respectively comprise 5-10 BN thin films, and the total thickness is 5-10 nm.

8. Double-junction Ga₂O₃The device is characterized by comprising a flexible substrate (1), a first BN thin film layer (2), Ga₂O₃Substrate (3), P-type Ga₂O₃Layer (4), N-type Ga₂O₃A layer (5), a ZnSe fluorescent layer (6), a visible light reflecting layer (7), a source electrode (8), a drain electrode (9) and a second BN thin film layer (10),

the flexible substrate (1), the first BN thin film layer (2), the Ga₂O₃Substrate (3), the P-type Ga₂O₃Layer (4) of the N-type Ga₂O₃The layer (5), the ZnSe fluorescent layer (6) and the visible light reflecting layer (7) are arranged from bottom to top in sequence;

the source electrode (8) and the drain electrode (9) are respectively positioned on the P-type Ga₂O₃Layer (4) of the N-type Ga₂O₃The layer (5), the ZnSe fluorescent layer (6) and the visible light reflecting layer (7) are formed on both sides of a laminated structure, and the source electrode (8) and the leakage current layerThe lower surface of the electrode (9) and the Ga₂O₃The upper surface of the substrate (3) is contacted;

the second BN thin film layer (10) is provided on the upper surfaces of the source electrode (8), the drain electrode (9), and the visible light reflection layer (7).

9. The double-junction Ga according to claim 8₂O₃Device characterized in that said P-type Ga₂O₃The doping element of the layer (4) is B or N with a doping concentration of 1 × 10²²-3×10²²cm^-3(ii) a The N-type Ga₂O₃The doping element of the layer (5) is P element with a doping concentration of 1 × 10²³-4×10²³cm^-3。

10. The double-junction Ga according to claim 8 or 9₂O₃The device is characterized in that the first BN thin film layer (2) and the second BN thin film layer (10) respectively comprise 5-10 BN thin films and the thickness is 5-10 nm.

Technical Field

The invention belongs to the technical field of microelectronics, and particularly relates to double-junction Ga₂O₃A device and a method of making the same.

Background

A double junction transistor (bipolar junction transistor) may be applied in high frequency as well as high power applications. Especially double junction transistors, may find particular end use in wireless communication systems and amplifiers for mobile devices, switches, oscillators, and the like. Double junction transistors are also used in high speed logic circuits.

SiC is the most advantageous semiconductor material for manufacturing high-temperature, high-power electronic devices due to its excellent physicochemical and electrical properties, and has a power device quality factor much greater than that of Si materials. The traditional double-junction type SiC device cannot break through the traditional double-junction type semiconductor device due to the reasons that the carrier mobility of SiC is not high and the voltage withstanding value is limited; and the double-junction SiC device has slow detection time for ultraviolet light exploration and cannot be applied to actual industry.

Disclosure of Invention

In order to solve the above problems in the prior art, the present invention provides a double-junction type Ga₂O₃A device and a method of making the same. The technical problem to be solved by the invention is realized by the following technical scheme:

one aspect of the present invention provides a double-junction type Ga₂O₃A method of making a device comprising:

s1: selecting a flexible substrate;

s2: covering a plurality of BN thin films on the upper surface of the flexible substrate to form a first BN thin film layer;

s3: providing Ga on the first BN thin film layer₂O₃Substrate and heating to heat the Ga₂O₃The substrate is tightly attached to the first BN thin film layer;

s4: in the Ga₂O₃Performing ion implantation on the substrate to form P-type Ga₂O₃A layer;

s5: in the P-type Ga₂O₃Ion implantation is performed on the layer to form N-type Ga₂O₃Layer of the N-type Ga₂O₃The thickness of the layer is less than that of the P-type Ga₂O₃The thickness of the layer;

s6: in the N-type Ga₂O₃Growing a ZnSe fluorescent layer on the upper surface of the layer;

s7: coating a visible light reflecting layer on the upper surface of the ZnSe fluorescent layer;

s8: respectively etching and manufacturing a source electrode and a drain electrode on two sides of the upper surface of the visible light reflecting layer, so that the lower surfaces of the source electrode and the drain electrode are respectively equal to the lower surfaces of the Ga₂O₃An upper surface contact of the substrate;

s9: and covering a plurality of BN thin films on the upper surfaces of the source electrode, the drain electrode and the visible light reflecting layer to form a second BN thin film layer.

In one embodiment of the invention, the flexible substrate is a PET flexible substrate with a thickness of 1-2mm, and the Ga₂O₃The thickness of the substrate was 150-200 μm.

In one embodiment of the present invention, in step S3, the heating temperature is 150-.

In one embodiment of the present invention, the P-type Ga₂O₃The doping element of the layer is B or N element with doping concentration of 1 × 10²²-3×10²²cm^-3The thickness is 5-10 μm.

In one embodiment of the present invention, the N-type Ga₂O₃The doping element of the layer is P element with doping concentration of 1 × 10²³-4×10²³cm^-3A thickness of2-5μm。

In one embodiment of the invention, the thickness of the ZnSe fluorescent layer is 60-100nm, the material of the visible light reflecting layer is Ag, and the thickness is 10-15 μm.

In one embodiment of the present invention, the first BN thin film layer and the second BN thin film layer include 5 to 10 BN thin films, respectively, and have a total thickness of 5 to 10 nm.

Another aspect of the present invention provides a double-junction type Ga₂O₃The device comprises a flexible substrate, a first BN film layer and Ga₂O₃Substrate, P-type Ga₂O₃Layer, N type Ga₂O₃A ZnSe fluorescent layer, a visible light reflecting layer, a source electrode, a drain electrode and a second BN film layer,

the flexible substrate, the first BN thin film layer, the Ga₂O₃Substrate and P-type Ga₂O₃Layer of the N-type Ga₂O₃The layer, the ZnSe fluorescent layer and the visible light reflecting layer are sequentially arranged from bottom to top;

the source electrode and the drain electrode are respectively positioned in the P-type Ga₂O₃Layer of the N-type Ga₂O₃Two sides of a laminated structure formed by the layer, the ZnSe fluorescent layer and the visible light reflecting layer, and the lower surfaces of the source electrode and the drain electrode and the Ga₂O₃An upper surface contact of the substrate;

the second BN thin film layer is arranged on the upper surfaces of the source electrode, the drain electrode and the visible light reflecting layer.

In one embodiment of the present invention, the P-type Ga₂O₃The doping element of the layer is B or N element with doping concentration of 1 × 10²²-3×10²²cm^-3(ii) a The N-type Ga₂O₃The doping element of the layer is P element with doping concentration of 1 × 10²³-4×10²³cm^-3。

In one embodiment of the present invention, the first BN thin film layer and the second BN thin film layer include 5 to 10 BN thin films, respectively, with a thickness of 5 to 10 nm.

Compared with the prior art, the invention has the beneficial effects that:

1. double-junction Ga of the present invention₂O₃The device comprises Ga₂O₃Substrate, Ga₂O₃The high-voltage-resistant high-voltage transformer has a wide band gap and is more stable and resistant to high temperature due to unique physical properties; optically, Ga₂O₃The response to ultraviolet light is very quick and has ultrahigh response coefficient, so that the prepared double-junction Ga₂O₃The device has excellent chip performance, can bear higher temperature and voltage, and can be applied to equipment and scenes with large voltage and high power.

2. Double-junction Ga of the present invention₂O₃The device is provided with the PET flexible substrate, so that the device can be used as a piezoelectric wearable sensor, the number of polarization charges in the device can be effectively increased by the double PN junctions, the polarization rate of the device is increased after strain, and the essential piezoelectric performance is enhanced, so that the calendaring electrical property of the device can be greatly improved, and the performance of the device as a piezoelectric sensor is improved.

3. The double-junction Ga₂O₃The device is covered with thin BN films on the top of the device and above the PET substrate, and the BN films and the device can generate an electron channel, so that the mobility is improved, and the stability and the electrical property of the device are improved.

The present invention will be described in further detail with reference to the accompanying drawings and examples.

Drawings

FIG. 1 shows a double-junction Ga according to an embodiment of the present invention₂O₃A flow chart of a method for manufacturing a device;

FIGS. 2a to 2g show a double-junction Ga according to an embodiment of the present invention₂O₃The preparation process of the device is shown schematically.

Description of reference numerals:

1-a flexible substrate; 2-a first BN thin film layer; 3-Ga₂O₃A substrate; 4-P type Ga₂O₃A layer; 5-ZnSe fluorescent layer; 6-visible light reflecting layer; 7-a source electrode; 8-a drain electrode; 9-a drain electrode; 10-secondAnd two BN thin film layers.

Detailed Description

To further illustrate the technical means and effects of the present invention for achieving the predetermined objects, a double-junction Ga according to the present invention is provided in the following with reference to the accompanying drawings and the detailed description₂O₃The device and the method for manufacturing the same are explained in detail.

The foregoing and other technical matters, features and effects of the present invention will be apparent from the following detailed description of the embodiments, which is to be read in connection with the accompanying drawings. The technical means and effects of the present invention adopted to achieve the predetermined purpose can be more deeply and specifically understood through the description of the specific embodiments, however, the attached drawings are provided for reference and description only and are not used for limiting the technical scheme of the present invention.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or device that comprises a list of elements does not include only those elements but may include other elements not expressly listed. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of additional like elements in the article or device comprising the element.

Example one

Referring to fig. 1, fig. 1 shows a double-junction Ga according to an embodiment of the present invention₂O₃A flow chart of a method for manufacturing a device. The double-junction Ga₂O₃The preparation method of the device comprises the following steps:

s1: and selecting a flexible substrate.

The flexible substrate is a PET (Polyethylene terephthalate) flexible substrate with the thickness of 1-2mm, the length of 2-3cm and the width of 2-3 cm. The thickness of the flexible substrate is selected to ensure that when strained, strain energy is accurately imparted to the device.

S2: covering a plurality of layers of BN films on the upper surface of the flexible substrate to form a first BN film layer.

Specifically, a square BN film with 5-10 layers, a total thickness of 5-10nm and a size of about 80-120 μm is transferred and placed on the center of the upper surface of the PET flexible substrate by using a transfer platform. The BN film has 5-10 layers, thus not influencing the whole thickness of the device and effectively improving the electron mobility of the device.

S3: providing Ga on the first BN thin film layer₂O₃The substrate is heated to cause Ga₂O₃The substrate is closely attached to the first BN film layer.

Specifically, 150-200 μm thick Ga grown epitaxially using a transfer platform₂O₃The substrate is transferred to the first BN film layer and heated at the temperature of 150-₂O₃The substrate is tightly attached to the BN film.

S4: using a fully automatic ion implanter in Ga₂O₃Carrying out doping element ion implantation on the substrate to form P-type Ga₂O₃And (3) a layer.

Formed P-type Ga₂O₃The doping element of the layer is B or N element with doping concentration of 1 × 10²²-3×10²²cm^-3The thickness is 5-10 μm.

S5: using a fully automatic ion implanter in P-type Ga₂O₃Implanting ions of doping elements on the layer to form N-type Ga₂O₃Layer of and N-type Ga₂O₃The thickness of the layer being less than that of P-type Ga₂O₃The thickness of the layer.

Specifically, N-type Ga₂O₃The doping element of the layer is P element with doping concentration of 1 × 10²³-4×10²³cm^-3The thickness is 2-5 μm.

S6: in the N-type Ga₂O₃And growing a ZnSe fluorescent layer on the upper surface of the layer at 700 ℃ by using a single-temperature-zone tubular furnace, wherein the thickness of the ZnSe fluorescent layer is 60-100 nm.

S7: and coating a visible light reflecting layer on the upper surface of the ZnSe fluorescent layer at a speed of 10nm/s by using a metal vapor deposition instrument, wherein the visible light reflecting layer is made of Ag and has a thickness of 10-15 mu m.

S8: respectively etching and manufacturing a source electrode and a drain electrode on two sides of the upper surface of the visible light reflecting layer, so that the lower surfaces of the source electrode and the drain electrode are respectively equal to Ga₂O₃An upper surface contact of the substrate;

specifically, the device is divided into an etching area and a non-etching area through photoetching, etching is carried out on two sides of the upper surface of the visible light reflecting layer through an etching process to form a source electrode groove and a drain electrode groove, then a source electrode and a drain electrode are respectively manufactured through a metal vapor deposition instrument, the electrode material is gold, the thickness is 20-25 mu m, and the lower surfaces of the source electrode and the drain electrode and Ga are respectively equal₂O₃The upper surface of the substrate is in contact.

S9: and covering a plurality of BN thin films on the upper surfaces of the source electrode, the drain electrode and the visible light reflecting layer to form a second BN thin film layer.

Specifically, a square BN thin film with the thickness of 5-10 layers, the total thickness of 5-10nm and the size of about 80-120 mu m is transferred and placed on the upper surface of the whole device by using a transfer platform so as to cover the upper surfaces of the source electrode, the drain electrode and the visible light reflecting layer.

Double junction type Ga of the present example₂O₃The device comprises Ga₂O₃Substrate, Ga₂O₃The high-voltage-resistant high-voltage transformer has a wide band gap and is more stable and resistant to high temperature due to unique physical properties; optically, Ga₂O₃The response to ultraviolet light is very quick and has ultrahigh response coefficient, so that the prepared double-junction Ga₂O₃The device has excellent chip performance, can bear higher temperature and voltage, and can be applied to equipment and scenes with large voltage and high power.

Example two

On the basis of the first embodiment, this embodiment describes in detail a double-junction Ga₂O₃A method for manufacturing a device. Referring to fig. 2a to fig. 2g, fig. 2a to fig. 2g are schematic views illustrating a manufacturing process of a double-junction Ga2O3 device according to an embodiment of the present invention. Book (I)The preparation method of the embodiment comprises the following steps:

step 1: selecting a flexible substrate 1, wherein the flexible substrate is a PET flexible substrate with the thickness of 2mm, the length of 3cm and the width of 3 cm.

Step 2: a square BN film having a thickness of 5 layers, a total thickness of 5nm, and a size of about 100 μm was transferred to the center of the above PET flexible substrate by using a transfer stage to form a first BN film layer 2, as shown in fig. 2 a.

And step 3: 150 thick Ga to be epitaxially grown using a transfer platform₂O₃The substrate 3 was transferred to a BN film and heated at 200 ℃ to cause Ga to be formed₂O₃The substrate 3 is closely attached to the first BN thin film layer 2 as shown in fig. 2 b.

And 4, step 4: in Ga₂O₃Performing ion implantation on the substrate to form P-type Ga₂O₃Layer 4, P-type Ga formed₂O₃The doping element of the layer 4 is B or N with a doping concentration of 2X 10²²cm^-3The thickness was 6 μm, as shown in FIG. 2 c.

And 5: in P-type Ga₂O₃Ion implantation is performed on the layer 4 to form N-type Ga₂O₃Layer 5, N-type Ga₂O₃The doping element of the layer 5 is P element with a doping concentration of 1 × 10²³cm^-3The thickness was 3 μm, as shown in FIG. 2 d.

Step 6: in the N-type Ga₂O₃And growing a ZnSe fluorescent layer 6 on the upper surface of the layer 5, wherein the thickness of the ZnSe fluorescent layer 6 is 80 nm.

And 7: and coating a visible light reflecting layer 7 on the upper surface of the ZnSe fluorescent layer 6, wherein the visible light reflecting layer 7 is made of Ag and has a thickness of 10 μm, as shown in FIG. 2 e.

And 8: respectively etching and manufacturing a source electrode 8 and a drain electrode 9 on two sides of the upper surface of the visible light reflecting layer 7, so that the lower surfaces of the source electrode 8 and the drain electrode 9 are respectively equal to Ga₂O₃The upper surface of the substrate 3 is contacted;

specifically, a source electrode 8 and a drain electrode 9 are respectively manufactured on two sides of the upper surface of the visible light reflecting layer 7 through photoetching and etching processes, the electrode material is gold, the thickness is 20 microns, and the source electrode8 and the lower surface of the drain electrode 9 are both in contact with Ga₂O₃The upper surface of the substrate 3 is contacted as shown in fig. 2 f.

And step 9: transferring a square BN thin film with the thickness of 5 layers, the total thickness of 5nm and the size of about 100 mu m to the upper surface of the whole device by using a transfer platform so as to cover the upper surfaces of the source electrode 8, the drain electrode 9 and the visible light reflecting layer 7, thereby completing the double-junction Ga₂O₃Preparation of the device, as shown in fig. 2 g.

Inventive double-junction Ga prepared in this example₂O₃The device is provided with the PET flexible substrate, so that the device can be used as a piezoelectric wearable sensor, the number of polarization charges in the device can be effectively increased by the double PN junctions, the polarization rate of the device is increased after strain, and the essential piezoelectric performance is enhanced, so that the calendaring electrical property of the device can be greatly improved, and the performance of the device as a piezoelectric sensor is improved.

EXAMPLE III

On the basis of the above embodiments, the present embodiment provides a double-junction Ga₂O₃A device. As shown in FIG. 2g, the double-junction type Ga₂O₃The device comprises a flexible substrate 1, a first BN thin film layer 2 and Ga₂O₃Substrate 3, P-type Ga₂O₃Layer 4, N-type Ga₂O₃A layer 5, a ZnSe fluorescent layer 6, a visible light reflecting layer 7, a source electrode 8, a drain electrode 9 and a second BN thin film layer 10, wherein the flexible substrate 1, the first BN thin film layer 2 and Ga₂O₃Substrate 3, P-type Ga₂O₃Layer 4, N-type Ga₂O₃The layer 5, the ZnSe fluorescent layer 6 and the visible light reflecting layer 7 are sequentially arranged from bottom to top; the source electrode 8 and the drain electrode 9 are respectively positioned in the P-type Ga₂O₃Layer 4, N-type Ga₂O₃The layer 5, the ZnSe fluorescent layer 6 and the visible light reflecting layer 7 were formed on both sides of the laminated structure, and the lower surfaces of the source electrode 8 and the drain electrode 9 were all in contact with Ga₂O₃The upper surface of the substrate 3 is contacted; the second BN thin film layer 10 is provided on the upper surfaces of the source electrode 8, the drain electrode 9, and the visible light reflective layer 7.

Further, P-type Ga₂O₃Doping element of layer 4Is B or N element with doping concentration of 1 × 10²²-7×10²²cm^-3The thickness is 5-10 μm; n type Ga₂O₃The doping element of the layer 5 is P element with a doping concentration of 1 × 10²³-8×10²³cm^-3The thickness is 2-5 μm.

Further, the flexible substrate is a PET (Polyethylene terephthalate) flexible substrate with the thickness of 1-2mm, the length of 2-3cm and the width of 2-3 cm; the first BN film layer 2 and the second BN film layer 10 respectively comprise 5-10 BN films, and the thickness is 5-10 nm.

Furthermore, the thickness of the ZnSe fluorescent layer is 60-100nm, the material of the visible light reflecting layer is Ag, the thickness is 10-15 μm, and the material of the electrode of the source electrode and the drain electrode is gold, and the thickness is 20-25 μm.

Double-junction Ga of the embodiment of the invention₂O₃The device is provided with the PET flexible substrate, so that the device can be used as a piezoelectric wearable sensor, and the double PN junctions of the device greatly improve the piezooptical electrical performance of the device and improve the performance of the device as the piezoelectric sensor. The double-junction Ga₂O₃The device is covered with thin BN films on the top of the device and above the PET substrate, and the BN films and the device can generate an electron channel, so that the mobility is improved, and the stability and the electrical property of the device are improved.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.