Preparation method of a box-shaped indirect heating phase change switching device

Abstract

A method for preparing a box-shaped, indirectly heated phase-change switching device belongs to the technical fields of microwave electronics and microwave switching devices. The present invention provides a method for preparing a box-shaped, indirectly heated phase-change switching device. This method utilizes photolithography and magnetron sputtering to form a four-end, indirect heating device, effectively achieving full enclosure of the phase-change layer by the heating material. When the heating layer material generates Joule heat under the control of an electric pulse, the heating layer material heats up rapidly and evenly, compared to conventional phase-change switching devices. This significantly shortens the information processing cycle time of the phase-change switch, making the operating state of the phase-change material more stable and enabling rapid state switching.

Description

Technical Field

[0001] The invention belongs to the technical field of microwave electronics and microwave switching devices, and particularly relates to a method for preparing a box-shaped indirect heating type phase change switching device. Background Art

[0002] Switching devices are an indispensable component of circuit systems and are widely used in digital logic circuits, storage computing, and radio frequency transmitter systems for signal reception or transmission. Phase-change switches are a special type of electronic switch primarily used to switch or modulate signals in radio frequency and microwave circuits. Because radio frequency and microwave signals are characterized by high frequency, high speed, and high precision, phase-change switches must exhibit fast, precise, and reliable switching performance. With the continued advancement of device design and application research, the fabrication methods of phase-change switches are expected to become a key technology in the electronic device field.

[0003] Currently, PIN diode switches offer advantages such as fast switching speed and small size, but they require a bias current to maintain their on-state, which results in high power consumption. FETs offer the advantage of good isolation between DC and RF circuits, low power consumption, simple manufacturing processes, and ease of integration. However, to reduce their on-resistance, the width of the transistor channel needs to be increased, which increases the parasitic (drain-source) capacitance of the switch, thereby reducing the isolation of the switch and resulting in a lower cutoff frequency. RF-MEMS switches can achieve extremely low insertion loss, high isolation, and linearity, offering broad application prospects. However, RF-MEMS switches also have issues such as the need for a high drive voltage to maintain mechanical movement, low switching speeds, contact degradation, difficulty integrating with CMOS, and high packaging costs.

[0004] The operating principle of devices made using phase change materials (PCMs) is based on the material's ability to change from a high-resistivity (amorphous) state to a low-resistivity (crystalline) state, and vice versa, under the influence of a short-duration heat pulse. Its DC power consumption is negligible. With the application of nanosecond voltage pulses, PCMs can provide resistance changes exceeding six orders of magnitude, making this technology ideal for low-loss, high-speed switching at microwave and millimeter-wave frequencies.

[0005] However, current phase change switches have problems that need to be solved urgently, such as slow heating speed and uneven heating. Summary of the Invention

[0006] The purpose of the present invention is to address the problems of difficult and uneven heating of existing phase change switches in the background art, and to propose a method for preparing a box-shaped indirect heating phase change switch device.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing a box-shaped indirect heating phase change switching device comprises the following steps:

[0009] Step 1: forming a substrate isolation layer on the substrate;

[0010] Step 2: performing photolithographic patterning on the substrate isolation layer and magnetron sputtering a heating layer thin film to form a first heating layer; the first heating layer is rectangular, and the first heating layer and the substrate isolation layer are concentric rectangles;

[0011] Step 3: Forming a first heating isolation layer on the substrate isolation layer and on both sides of the first heating layer using a photolithography process and a deposition process; one end of the first heating isolation layer is flush with the edge of the substrate isolation layer, and the other end is closely attached to the first heating layer, and the width of the first heating isolation layer is smaller than the width of the first heating layer;

[0012] Step 4: forming a second heating isolation layer on the first heating layer using a photolithography process and a deposition process; the second heating isolation layer is in the shape of a long strip, perpendicular to the first heating isolation layer, and its two ends are flush with the two ends of the substrate isolation layer, and the second heating isolation layer does not completely cover the first heating layer;

[0013] Step 5: Using photolithography and magnetron sputtering, a phase change layer is formed on the second heating isolation layer; the phase change layer is rectangular, the phase change layer and the first heating layer are concentric rectangles, and the overlapping area of ​​the first heating layer and the second heating isolation layer completely covers the phase change layer;

[0014] Step 6: Using photolithography and magnetron sputtering, a signal transmission electrode layer is formed on both sides of the phase change layer. The signal transmission electrode layer includes a first signal transmission electrode located on one side of the phase change layer and a second signal transmission electrode located on the other side of the phase change layer. One end of the first signal transmission electrode and the second signal transmission electrode are flush with the edge of the second heating isolation layer, and the other end is in close contact with the phase change layer.

[0015] Step 7: using a photolithography lift-off process and magnetron sputtering to form a third heating isolation layer on the phase change layer; the third heating isolation layer completely covers the phase change layer;

[0016] Step 8: Deposit a heating layer film on the third heating isolation layer, the first heating isolation layer and part of the first heating layer as a second heating layer; the second heating layer is connected to the first heating layer to fully surround the phase change material; the obtained structure is subjected to annealing and other process treatments to obtain the phase change switch device.

[0017] Furthermore, the substrate is silicon (Si), gallium arsenide (GaAs) or sapphire (Al2O3), etc.; the substrate isolation layer is an electrical insulating material such as silicon dioxide (SiO2), aluminum nitride (AlN), silicon nitride (Si3N4), etc.

[0018] Furthermore, the first heating layer and the second heating layer are made of nickel-chromium-silicon (NiCrSi), nickel-chromium (NiCr), tungsten (W) or titanium-tungsten (TiW).

[0019] Furthermore, the materials of the first heating isolation layer, the second heating isolation layer and the third heating isolation layer are Si3N4, AlN, diamond (C) and the like.

[0020] Furthermore, the phase change layer material is a chalcogenide compound such as germanium telluride (GeTe), germanium antimony telluride (GeSbTe) or germanium selenide telluride (GeSeTe).

[0021] Furthermore, the material of the signal transmission electrode layer is gold (Au), copper (Cu) or aluminum (Al).

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention provides a method for preparing a box-shaped indirect heating phase change switch device, which adopts photolithography and magnetron sputtering to form a four-end surrounded indirect heating device, that is, the heating material fully surrounds the phase change layer; when the heating layer material generates Joule heat under the control of electric pulses, compared with ordinary phase change switch devices, it will achieve rapid temperature rise and can evenly heat the phase change layer material, greatly shortening the information processing cycle time of the phase change switch, making the working state of the phase change material more stable, and can quickly switch states. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic flow chart of a method for preparing a box-shaped indirect heating phase change switch device provided by the present invention;

[0025] Figure 2 Schematic diagram of a longitudinal cross-section of a structure after a substrate isolation layer is grown on a substrate; 1 is a substrate, and 2 is a substrate isolation layer;

[0026] Figure 3 For Figure 2 A longitudinal cross-sectional diagram of a structure after photolithographic patterning is performed on the basis of FIG; wherein 1 is a substrate, 2 is a substrate isolation layer, and 7 is a photoresist;

[0027] Figure 4 For Figure 3 A longitudinal cross-sectional diagram of a structure after growing a heating layer material on the basis of FIG. 1 ; wherein 1 is a substrate, 2 is a substrate isolation layer, 3 is a heating layer material, and 7 is a photoresist;

[0028] Figure 5 For the general Figure 4 A cross-sectional view of the structure after the photoresist of the structure is stripped; wherein 3-1 is the first heating layer;

[0029] Figure 6 for Figure 5 A top view of the structure;

[0030] Figure 7 4-1 is a longitudinal cross-sectional diagram of a structure after a first heating isolation layer is grown on a substrate isolation layer;

[0031] Figure 8 for Figure 7 A top view of the structure;

[0032] Figure 9 For Figure 7 A schematic longitudinal cross-sectional view of the structure after photolithographic patterning is performed on the structure;

[0033] Figure 10 For Figure 9 A schematic longitudinal cross-sectional view of the structure after a second heating and isolating layer is grown on the structure; wherein 4-2 is the material of the second heating and isolating layer;

[0034] Figure 11 for Figure 10 a cross-sectional view of the structure after photoresist removal;

[0035] Figure 12 for Figure 11 A top view of the structure;

[0036] Figure 13 For Figure 10 Schematic cross-sectional view of the structure after a phase change layer is grown on the structure; wherein 5 is the phase change layer;

[0037] Figure 14 for Figure 13 A top view of the structure;

[0038] Figure 15 For Figure 13 A top view of the structure after a signal transmission electrode layer is grown on the structure; wherein 6-1 is a first signal transmission electrode, and 6-2 is a second signal transmission electrode;

[0039] Figure 16 For Figure 15 A schematic longitudinal cross-sectional view of the structure after the third heating and insulating layer is formed on the structure; wherein 4-3 is the material of the third heating and insulating layer;

[0040] Figure 17 for Figure 16 A top view of the structure;

[0041] Figure 18 For Figure 16 Schematic diagram of the structure after the second heating layer is grown on the structure; wherein 3-2 is the second heating layer;

[0042] Figure 19 for Figure 18 A top view of the structure;

[0043] Figure 20 This is a schematic diagram of a three-dimensional model of the boxed indirect heating phase change switch device proposed by the present invention. DETAILED DESCRIPTION

[0044] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0045] Example

[0046] Phase change material films have two states: crystalline and amorphous. When the phase change material film is in the crystalline state, a narrow and high voltage (current) pulse is applied to the heating layer for local heating, and the phase change material film is heated to above the melting temperature. The quenching changes the crystal state of the material, making the phase change material amorphous. At this time, it is in a high resistance state, and the switch is in the "off" state; when the film is in the amorphous state, a continuous wide and low voltage (current) pulse is applied to heat the phase change material film to above the crystallization temperature to achieve the transition from amorphous to crystalline state. At this temperature, the growth and nucleation of crystalline particles are achieved, thereby converting the phase change material from the amorphous state to the crystalline state, and from the high resistance state to the low resistance state. At this time, the switch is in the "on" state. When the switch is in the "on" state, the signal can be transmitted from the input end of the signal transmission electrode through the phase change layer material of the switching device to the output port of the signal transmission electrode to realize signal transmission. When the switch is in the "off" state, the signal cannot pass through the phase change layer material and the signal cannot be transmitted.

[0047] A method for preparing a box-shaped indirect heating phase change switch device comprises the following steps:

[0048] Step 1: Clean the substrate in acetone, ethanol and deionized water in sequence, blow dry, and then place it in a plasma cleaning machine for cleaning;

[0049] Step 2: A substrate isolation layer is formed on the cleaned substrate using a plasma enhanced chemical vapor deposition (PECVD) method. Figure 2 As shown;

[0050] Step 3: Perform photolithography patterning on the substrate isolation layer to form a photoresist 7, such as Figure 3 As shown;

[0051] Step 4: Sputter a heating layer film 3 on the structure obtained in step 3, and the heating layer film covers the photoresist and the exposed substrate isolation layer, as shown in FIG. Figure 4 As shown;

[0052] Step 5: Remove the photoresist and the heating layer film on the photoresist to form a first heating layer, such as Figure 5 As shown; the first heating layer is a rectangle, and the first heating layer and the substrate isolation layer are concentric rectangles, as shown Figure 6 As shown;

[0053] Step 6: Using photolithography and plasma enhanced chemical vapor deposition (PECVD) process to form a first heating isolation layer on the substrate isolation layer and on both sides of the first heating layer, as shown in FIG. Figure 7 As shown; one end of the first heating isolation layer is flush with the edge of the substrate isolation layer, and the other end is close to the first heating layer. The width of the first heating isolation layer is smaller than the width of the first heating layer, as shown Figure 8 As shown;

[0054] Step 7: Photolithography is performed on the first heating isolation layer. The photoresist 7 covers the first heating isolation layer and both ends of the first heating layer, exposing the pattern of the second heating isolation layer. Figure 9 As shown;

[0055] Step 8: Deposit a heating isolation layer material on the structure formed in step 7 to obtain a structure such as Figure 10 As shown;

[0056] Step 9: stripping the photoresist and forming a second heating isolation layer on the first heating layer. Figure 11 As shown; the second heating isolation layer is a long strip, the second heating isolation layer is perpendicular to the first heating isolation layer, and its two ends are flush with the upper and lower ends of the substrate isolation layer, and the second heating isolation layer does not completely cover the first heating layer, as shown Figure 12 As shown;

[0057] Step 10: Using photolithography and magnetron sputtering, a phase change layer is formed on the second heating isolation layer, such as Figure 13 As shown; the phase change layer is a rectangle, the phase change layer and the first heating layer are concentric rectangles, and the overlapping area of ​​the first heating layer and the second heating isolation layer completely covers the phase change layer, the width of the phase change layer is less than the width of the second heating isolation layer, and the length is equal to the width of the first heating isolation layer, as shown Figure 14 As shown;

[0058] Step 11: Use photolithography and magnetron sputtering to form signal transmission electrode layers on both sides of the phase change layer. The signal transmission electrode layer includes a first signal transmission electrode 6-1 located on one side of the phase change layer and a second signal transmission electrode 6-2 located on the other side of the phase change layer, which are used for signal transmission. One end of the first signal transmission electrode and the second signal transmission electrode are flush with the edge of the second heating isolation layer, and the other end is close to the phase change layer. Figure 15 As shown;

[0059] Step 12: Using photolithography and magnetron sputtering, a third heating isolation layer is formed on the phase change layer. Figure 16 As shown; the third heating isolation layer completely covers the phase change layer, the length of the third heating isolation layer is equal to the length of the phase change layer, and the width is greater than the width of the phase change layer, as shown Figure 17 As shown;

[0060] Step 13: depositing a heating layer thin film on the third heating isolation layer, the first heating isolation layer and part of the first heating layer as the second heating layer, such as Figure 18-19 As shown, the length of the second heating layer is equal to the length of the substrate, and the width is equal to the width of the first heating isolation layer; the second heating layer is connected to the first heating layer to fully surround the phase change material; after the obtained structure is annealed, the phase change switch device can be obtained. The schematic diagram of the three-dimensional structural model of the obtained phase change switch device is shown in Figure 20 shown.

Claims

1. A method for preparing a box-shaped indirect heating phase change switching device, characterized in that: The following steps are involved: Step 1: forming a substrate isolation layer on the substrate; Step 2: performing photolithographic patterning on the substrate isolation layer and magnetron sputtering a heating layer thin film to form a first heating layer; the first heating layer is rectangular, and the first heating layer and the substrate isolation layer are concentric rectangles; Step 3: Forming a first heating isolation layer on the substrate isolation layer and on both sides of the first heating layer using a photolithography process and a deposition process; one end of the first heating isolation layer is flush with the edge of the substrate isolation layer, and the other end is closely attached to the first heating layer, and the width of the first heating isolation layer is smaller than the width of the first heating layer; Step 4: forming a second heating isolation layer on the first heating layer using a photolithography process and a deposition process; the second heating isolation layer is in the shape of a long strip, perpendicular to the first heating isolation layer, and its two ends are flush with the two ends of the substrate isolation layer, and the second heating isolation layer does not completely cover the first heating layer; Step 5: Using photolithography and magnetron sputtering, a phase change layer is formed on the second heating isolation layer; the phase change layer is rectangular, the phase change layer and the first heating layer are concentric rectangles, and the overlapping area of ​​the first heating layer and the second heating isolation layer completely covers the phase change layer; Step 6: Using photolithography and magnetron sputtering, a signal transmission electrode layer is formed on both sides of the phase change layer. The signal transmission electrode layer includes a first signal transmission electrode located on one side of the phase change layer and a second signal transmission electrode located on the other side of the phase change layer. One end of the first signal transmission electrode and the second signal transmission electrode are flush with the edge of the second heating isolation layer, and the other end is in close contact with the phase change layer. Step 7: Using a photolithography lift-off process and a deposition process, a third heating isolation layer is formed on the phase change layer; the third heating isolation layer completely covers the phase change layer; Step 8: Deposit a heating layer film on the third heating isolation layer, the first heating isolation layer and part of the first heating layer as a second heating layer; the second heating layer is connected to the first heating layer to fully surround the phase change material; the obtained structure is annealed to obtain the phase change switching device.

2. The method for preparing a box-shaped indirect heating type phase change switching device according to claim 1, characterized in that: The substrate is made of silicon, gallium arsenide or sapphire, and the substrate isolation layer is made of silicon dioxide, aluminum nitride or silicon nitride.

3. The method for preparing a box-shaped indirect heating type phase change switch device according to claim 1, characterized in that: The materials of the first heating layer and the second heating layer are nickel-chromium-silicon, nickel-chromium, tungsten or titanium-tungsten.

4. The method for preparing a box-shaped indirect heating type phase change switch device according to claim 1, characterized in that: The materials of the first heating isolation layer, the second heating isolation layer and the third heating isolation layer are Si3N4, AlN or diamond.

5. The method for preparing a box-shaped indirect heating phase change switching device according to claim 1, wherein: The phase change layer material is GeTe, GeSbTe or GeSeTe.

6. The method for preparing a box-shaped indirect heating type phase change switch device according to claim 1, characterized in that: The material of the signal transmission electrode layer is Au, Cu or Al.

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