Low-current high-power chip, design method thereof and semiconductor laser

Abstract

The invention relates to a low-current high-power chip and a design method thereof, and a semiconductor laser, which are used for solving the technical problems that a rectifying circuit of an existing handheld medical beauty device is relatively complicated in design, relatively large in overall size, relatively high in cost and the like. The low-current high-power chip comprises an N-type substrate layer, a quantum well module and a P-type contact layer which are sequentially arranged from bottom to top, the N-type substrate layer is used for providing a substrate for the quantum well module; the quantum well module comprises n layers of quantum well units, the structural size and performance parameter of each layer of quantum well unit are the same, and n is greater than or equal to 2 and less than or equal to 5; two adjacent layers of quantum well units are connected in series through trap tunnel junctions; the quantum well unit at the bottommost layer is connected in series with the N-type substrate layer, and the quantum well unit at the topmost layer is connected in series with the P-type contact layer; the P-type contact layer is used for improving the stability of the device. Compared with an existing chip with the same power, the current of the chip is remarkably reduced.

Description

Technical Field

[0001] The invention relates to a semiconductor laser device, and in particular to a low-current high-power chip, a design method and a semiconductor laser. Background Art

[0002] With the development of technology, lasers have been fully applied in various fields, especially semiconductor lasers, which have been widely used in medical cosmetology, material processing, laser communication and other fields due to their advantages such as small size, low cost and easy integration.

[0003] At present, handheld medical aesthetic devices for medical aesthetics mostly use single quantum well chip epitaxial structures, which often need to match a larger input current when outputting a certain fixed power, and a larger input current requires a corresponding larger capacity source battery or the use of a current amplifier, which makes the design of the rectifier circuit of the power supply more complicated, increases the overall size of the device, and increases the design cost, greatly hindering its application in the field of medical aesthetics. Therefore, how to design a small device with high power semiconductor laser device has become an urgent problem to be solved. Summary of the invention

[0004] The purpose of the present invention is to solve the technical problems of the existing high-power laser device, such as the complex rectification circuit design, large overall size and high cost, and to provide a low-current high-power chip, design method and semiconductor laser.

[0005] In order to achieve the above objectives, the technical solutions provided by the present invention are as follows:

[0006] A low current, high power chip that is special in that:

[0007] It includes an N-type substrate layer, a quantum well module and a P-type contact layer arranged in sequence from bottom to top;

[0008] The N-type substrate layer is used to provide a base for the quantum well module and is used to connect to the positive electrode of an external power source;

[0009] The quantum well module comprises n layers of quantum well units placed in a stacked manner, and the structural dimensions and performance parameters of each layer of quantum well units are the same, wherein 2≤n≤5; two adjacent layers of quantum well units are connected in series via trap tunnel junctions; the quantum well unit at the bottom layer is connected in series with the N-type substrate layer, and the quantum well unit at the top layer is connected in series with the P-type contact layer;

[0010] The P-type contact layer is used to improve the stability of the device and is used to connect to the negative electrode of an external power source.

[0011] Furthermore, the number of the quantum well units is 3 layers.

[0012] The present invention also provides a design method for the above-mentioned low-current high-power chip, comprising the following steps:

[0013] Step 1: Based on the output power required by the semiconductor laser device, the number of quantum well units required in the chip is calculated and determined;

[0014] Step 2, prepare the substrate layer, the contact layer, and the corresponding number of quantum well units calculated in step 1, and stack the quantum well units of each layer in sequence;

[0015] Step 3, connecting two adjacent layers of quantum well units in series through trap tunnel junctions to obtain a quantum well module;

[0016] Step 4: Connect the substrate layer, quantum well module, and contact layer in series from bottom to top to obtain a low-current, high-power chip.

[0017] Furthermore, step 1 is specifically to calculate and obtain the output current of the semiconductor laser device based on the output power required by the semiconductor laser device, and then calculate and obtain the number of quantum well units in the semiconductor laser device chip based on the output current.

[0018] In addition, the present invention also provides a low-current high-power semiconductor laser, which is special in that:

[0019] It includes a power module and the above-mentioned low-current high-power chip connected to the power module;

[0020] The positive electrode of the power module is connected to the N-type substrate layer, and the negative electrode is connected to the P-type contact layer, which is used to supply power to the chip and drive the chip to work.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. A low-current high-power chip proposed in the present invention includes an N-type substrate layer, a quantum well module and a P-type contact layer, wherein the quantum well module includes n layers of quantum well units arranged in a stacked manner, 2≤n≤5, and the number of quantum well units can be adjusted as needed. Compared with existing chips with the same power, the current is significantly reduced.

[0023] 2. The present invention proposes a design method for a low-current high-power chip. Based on the output power required by the semiconductor laser device, by reasonably controlling the number of quantum well units in the chip, the working current of the semiconductor laser device is reduced exponentially when the same power is achieved, thereby greatly reducing the design cost, and the structure of the overall device is simpler and the size is more compact.

[0024] 3. The low-current high-power semiconductor laser proposed in the present invention removes the rectification control unit on the basis of the existing structure, and only requires a power module to drive the chip to work. Therefore, the manufacturing cost is significantly reduced, and the device size is greatly reduced, making the semiconductor laser more competitive in the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The figure is a schematic structural diagram of a low current high power chip embodiment of the present invention.

[0026] Figure 2 The figure is a schematic diagram of the circuit structure of a low current high power semiconductor laser embodiment of the present invention. DETAILED DESCRIPTION

[0027] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Reference Figure 1 This embodiment provides a low-current high-power chip, including an N-type substrate layer, a quantum well module and a P-type contact layer arranged in sequence from bottom to top; wherein the N-type substrate layer is connected to the positive pole of an external power supply and is used to provide a base for the quantum well module, and the P-type contact layer is connected to the negative pole of the external power supply and is used to improve the stability of the device.

[0029] The quantum well module includes n layers of quantum well units placed in a stacked manner, and the structural dimensions and performance parameters of each layer of quantum well units are the same, where 2≤n≤5; two adjacent layers of quantum well units are connected in series through trap tunnel junctions; the quantum well unit at the bottom layer is connected in series with the N-type substrate layer, and the quantum well unit at the top layer is connected in series with the P-type contact layer.

[0030] This embodiment is specifically explained by taking three-layer quantum well units as an example. The chip of the present invention adds two layers of quantum well units on the original single quantum well structure, and the two adjacent layers of quantum well units are connected in series with trap tunnel junctions. When the same power is achieved, the working current will be reduced exponentially. The improved chip only needs 1 / 3 of the current of the original chip.

[0031] Specifically, it has been found that adding P-type doping will effectively reduce the voltage of a single junction, thereby maintaining the photoelectric conversion efficiency of the chip. Here, a multi-quantum well structure is used, such as the above-mentioned triple quantum well structure (i.e., a structure including three layers of quantum well units). Under the same power, the current will be reduced. The following is an example using the formula P = UI:

[0032] For a single quantum well, that is, there is only one light-emitting area, assuming that a current of 8A is supplied, a power output of 8W can be achieved. For a triple quantum well structure, since the three quantum wells are in series, that is, each of the three light-emitting areas has a current of 8A, it is possible to achieve a power output of 8W times 3, or 24W. Conversely, if the triple quantum well structure is to achieve a power output of 8W, the current only needs 8 / 3A. It can be seen that the current of the chip using this structure is significantly reduced. According to the test results of the chip with a triple quantum well structure, the voltage of the triple quantum well is three times that of the single quantum well. This result also once again verifies the effectiveness of this solution.

[0033] The specific design structure and parameters of the three-layer quantum well unit of this embodiment are shown in Table 1:

[0034] Table 1 Structure and parameters of each quantum well unit

[0035]

[0036]

[0037] In addition, in this embodiment, the main function of the P-type contact layer is to improve the performance and reliability of gallium nitride (GaN)-based devices. The P-type contact layer, as an important semiconductor structure, plays a key role in improving the performance and reliability of GaN-based devices. Especially in lasers operating at high current density, the impact of the P-type ohmic contact is particularly significant. By adopting a specific contact layer structure and metal deposition technology, a low-resistance P-type ohmic contact can be obtained, which is crucial for reducing the specific contact resistivity and improving the conductivity of the device.

[0038] The design and optimization of the P-type contact layer not only involves the selection of materials and the control of doping concentration, but also includes surface treatment technology and optimization of the contact interface. Through these measures, the conductivity and stability of the P-type contact layer can be significantly improved, thereby improving the performance of the entire GaN-based device.

[0039] The two adjacent quantum well units are connected in series through a trap tunnel junction. The functions of the trap tunnel junction are: first, the trap tunnel junction is used to modulate the light field lased from the two adjacent quantum wells; second, to connect the adjacent quantum well units and connect the quantum well structures of the lasing wavelength in series through the trap tunnel junction.

[0040] The present invention also provides a design method for a low-current high-power chip, comprising the following steps:

[0041] Step 1: Based on the output power required by the semiconductor laser device, calculate and obtain its output current, and then calculate and determine the number of quantum well units required in its chip based on the output current.

[0042] Regarding the calculation of the number of quantum well units, there is no fixed formula to accurately calculate it because there are many complex influencing factors such as design materials and processes, but it can be determined by the following method.

[0043] First, let us introduce a concept - current density. Current density refers to the current intensity on the electrode per unit area. Its magnitude is equal to the amount of electricity passing through a unit area per unit time (current intensity), that is, J = I / S, where J represents current density, I represents current intensity, and S represents area.

[0044] Since the shape of the chip is generally a rectangular structure, it has length, width, and height. The length (i.e., the cavity length of the chip) does not affect the design of the quantum well. The width and height need to be considered. The width is the strip width of the chip, and the height direction is the design point of the quantum well. For example, if you need to design a chip that can achieve 10W power at a current of 10A. Assuming that the chip is designed with a strip width of 100μm, and 3 quantum well units are designed, each with a size of 4.5μm, the height of the chip is (4.5×3)μm, and the cross-sectional area of ​​the chip is (4.5×3×100)μm. 2 At this time, the current density J = 10A / (4.5×3×100)μm 2 ≈0.074(MA / cm 2 ). Similarly, when the chip width remains unchanged, a single quantum well is designed, and the current density J = 10A / (4.5×100)μm 2 ≈0.22(MA / cm 2 ).

[0045] According to empirical values, the above current density value should not exceed 14 (MA / cm 2 ), therefore, the size, number and chip width of each quantum well unit can be adjusted according to actual needs, so that the current density value can be designed to be 10 (MA / cm 2 ) to meet the design requirements. Because coating is an important step in the semiconductor laser process and affects production efficiency, the current density value has a greater impact on the coating quality. If it exceeds the above empirical value (i.e. 14 (MA / cm 2 )) or far below this value, a low-quality coating layer will be produced. The significance of designing the multi-quantum well in this embodiment is to effectively reduce the current density and the pressure on the coating layer when achieving the same power, thereby effectively improving production efficiency.

[0046] Step 2: prepare the substrate layer, the contact layer, and the corresponding number of quantum well units calculated in step 1, and stack the quantum well units in sequence.

[0047] Step 3: connect two adjacent layers of quantum well units in series through trap tunnel junctions to obtain a quantum well module.

[0048] Step 4: Connect the substrate layer, quantum well module, and contact layer in series from bottom to top to obtain a low-current, high-power chip.

[0049] Reference Figure 2 This embodiment also provides a low-current high-power semiconductor laser, including a power module and a low-current high-power chip connected to the power module. The positive electrode of the power module is connected to the N-type substrate layer, and the negative electrode is connected to the P-type contact layer, which is used to power the chip and drive the chip to work.

[0050] The semiconductor laser of this embodiment removes the rectifier control unit in the power control part, and only needs power drive; at the same time, the power supply selects a relatively mature standard product on the market with a lower price. Therefore, the overall manufacturing cost is significantly reduced, and the size of the device is greatly reduced. In addition, the handheld medical beauty device using the chip of this embodiment has a higher light intensity and a wider width, and has stronger market competitiveness.

[0051] Although the above embodiments have described the present invention in detail, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the present invention.

Claims

1. A low current high power chip, characterized in that: It includes an N-type substrate layer, a quantum well module and a P-type contact layer arranged in sequence from bottom to top; The N-type substrate layer is used to provide a base for the quantum well module and is used to connect to the positive electrode of an external power source; The quantum well module comprises n layers of quantum well units placed in a stacked manner, and the structural dimensions and performance parameters of each layer of quantum well units are the same, wherein 2≤n≤5; two adjacent layers of quantum well units are connected in series via trap tunnel junctions; the quantum well unit at the bottom layer is connected in series with the N-type substrate layer, and the quantum well unit at the top layer is connected in series with the P-type contact layer; The P-type contact layer is used to improve the stability of the device and is used to connect to the negative electrode of an external power source.

2. The low current high power chip according to claim 1, characterized in that: The number of the quantum well units is 3.

3. A design method for a low current high power chip according to claim 1 or 2, characterized in that: The following steps are involved: Step 1: Based on the output power required by the semiconductor laser device, the number of quantum well units required in the chip is calculated and determined; Step 2, prepare the substrate layer, the contact layer, and the corresponding number of quantum well units calculated in step 1, and stack the quantum well units of each layer in sequence; Step 3, connecting two adjacent layers of quantum well units in series through trap tunnel junctions to obtain a quantum well module; Step 4: Connect the substrate layer, quantum well module, and contact layer in series from bottom to top to obtain a low-current, high-power chip.

4. The design method of the low current high power chip according to claim 1, characterized in that: Step 1 specifically includes calculating and obtaining the output current of the semiconductor laser device based on the output power required by the semiconductor laser device, and then calculating and obtaining the number of quantum well units in the semiconductor laser device chip based on the output current.

5. A low current high power semiconductor laser, characterized in that: A low-current high-power chip according to claim 1 or 2, comprising a power module and the power module; The positive electrode of the power module is connected to the N-type substrate layer, and the negative electrode is connected to the P-type contact layer, which is used to supply power to the chip and drive the chip to work.

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