CN115133403A - Low-power-loss semiconductor laser and preparation method thereof - Google Patents

Low-power-loss semiconductor laser and preparation method thereof Download PDF

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CN115133403A
CN115133403A CN202210754306.0A CN202210754306A CN115133403A CN 115133403 A CN115133403 A CN 115133403A CN 202210754306 A CN202210754306 A CN 202210754306A CN 115133403 A CN115133403 A CN 115133403A
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doping
semiconductor laser
power loss
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郑婉华
徐传旺
齐爱谊
渠红伟
周旭彦
王天财
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Institute of Semiconductors of CAS
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/30—Structure or shape of the active region; Materials used for the active region
    • H01S5/305—Structure or shape of the active region; Materials used for the active region characterised by the doping materials used in the laser structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/04—Processes or apparatus for excitation, e.g. pumping, e.g. by electron beams
    • H01S5/042—Electrical excitation ; Circuits therefor
    • H01S5/0421—Electrical excitation ; Circuits therefor characterised by the semiconducting contacting layers

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Abstract

The present disclosure provides a low power loss semiconductor laser and a method for manufacturing the same, the device comprising: the semiconductor substrate layer, and an N-type limiting layer, an N-type waveguide layer, an active layer, a P-type waveguide layer, a P-type limiting layer and an ohmic contact layer which are sequentially stacked and extended on the semiconductor substrate layer; the P-type limiting layer comprises a first P-type sub-limiting layer and a second P-type sub-limiting layer which are stacked, and the first P-type sub-limiting layer is close to the P-type waveguide layer; the doping concentrations of the semiconductor substrate layer, the N-type limiting layer, the second P-type sub-limiting layer and the ohmic contact layer are kept unchanged along the thickness change along the epitaxial direction, the change of the doping gas flow along with time is a constant, the doping concentrations and the thicknesses of the N-type waveguide layer, the P-type waveguide layer and the first P-type sub-limiting layer all meet a quadratic function relationship, and the change of the doping gas flow along with time all meets the quadratic function relationship. The device can achieve very low power loss.

Description

Low-power-loss semiconductor laser and preparation method thereof
Technical Field
The disclosure relates to the technical field of semiconductor lasers, in particular to a low-power-loss semiconductor laser and a preparation method thereof.
Background
The semiconductor laser has the advantages of high power, strong reliability, long service life, small volume, low cost and the like, and is widely applied to the fields of pumping, medical treatment, communication and the like.
The low power loss and high electro-optic conversion efficiency are important performance indexes for researching high-power semiconductor lasers, which means less energy loss, and the stability and reliability of the devices are greatly improved.
After the thickness and the material of each layer in the epitaxial direction of the semiconductor laser are determined, the doping concentration greatly influences the performance of the device. The excessively high doping concentration can effectively reduce the series resistance of the device and reduce the joule heat loss caused by the series resistance. However, too high a doping concentration also increases the absorption loss of carriers. It is therefore important to select the appropriate doping concentration.
Disclosure of Invention
In view of the above technical problem, a first aspect of the present disclosure provides a low power loss semiconductor laser including: the semiconductor substrate layer, and an N-type limiting layer, an N-type waveguide layer, an active layer, a P-type waveguide layer, a P-type limiting layer and an ohmic contact layer which are sequentially stacked and extended on the semiconductor substrate layer; the P-type limiting layer comprises a first P-type sub-limiting layer and a second P-type sub-limiting layer which are stacked, and the first P-type sub-limiting layer is close to the P-type waveguide layer; the doping concentrations of the semiconductor substrate layer, the N-type limiting layer, the second P-type sub-limiting layer and the ohmic contact layer are kept unchanged along the thickness change along the epitaxial direction, the change of the doping gas flow along with time is a constant, the doping concentrations and the thicknesses of the N-type waveguide layer, the P-type waveguide layer and the first P-type sub-limiting layer all meet a quadratic function relationship, and the change of the doping gas flow along with time all meets the quadratic function relationship.
According to the embodiment of the disclosure, the doping concentration of the semiconductor substrate layer and the N-type limiting layer along the epitaxial direction is 2 multiplied by 10 18 cm -3 。
In the epitaxial direction, according to an embodiment of the present disclosureThe doping concentration of the two P-type sub-confinement layers and the ohmic contact layer is 10 19 cm -3 。
According to the embodiment of the disclosure, the corresponding characteristic optical field intensity of the subdivision points of the N-type waveguide layer, the P-type waveguide layer and the first P-type sub-confinement layer along the epitaxial direction is more than 10 -7 。
According to the embodiment of the disclosure, the characteristic optical field intensity of the semiconductor substrate layer, the N-type confinement layer, the second P-type sub-confinement layer and the ohmic contact layer corresponding to the subdivision point along the epitaxial direction is less than 10 -7 。
According to an embodiment of the present disclosure, the active layer is undoped.
According to the embodiment of the disclosure, the quadratic function relation of the change of the doping gas flow of the N-type waveguide layer, the P-type waveguide layer and the first P-type sub-confinement layer along with time is determined by the doping concentration and the growth rate of the corresponding layers.
According to the embodiment of the disclosure, the N-type waveguide layer comprises a plurality of stacked N-type sub-waveguide layers, the doping concentration and the thickness of each N-type sub-waveguide layer satisfy a quadratic function relationship, and the change of the doping gas flow along with the time is a quadratic function relationship.
According to an embodiment of the present disclosure, the thickness of the active layer is less than 100 nm.
A second aspect of the present disclosure provides a method for manufacturing a low power loss semiconductor laser, including: the N-type limiting layer, the N-type waveguide layer, the active layer, the P-type waveguide layer, the P-type limiting layer and the ohmic contact layer are sequentially arranged on the semiconductor substrate layer in an epitaxial and laminated mode; the P-type confinement layer comprises a first P-type sub-confinement layer and a second P-type sub-confinement layer which are stacked, and the first P-type sub-confinement layer is close to the P-type waveguide layer; in the epitaxial process, along the epitaxial direction, the doping concentrations of the semiconductor substrate layer, the N-type limiting layer, the second P-type sub-limiting layer and the ohmic contact layer are kept unchanged along the thickness change, the change of the doping gas flow along with time is a constant, the doping concentrations and the thicknesses of the N-type waveguide layer, the P-type waveguide layer and the first P-type sub-limiting layer all meet the quadratic function relationship, and the change of the doping gas flow along with time all meets the quadratic function relationship.
According to the low-power-loss semiconductor laser provided by the embodiment of the disclosure, at least the following beneficial effects are achieved:
each layer of the semiconductor laser is split along the epitaxial direction, and proper doping concentration is selected at each split point, so that the doping concentrations of the semiconductor substrate layer, the N-type limiting layer, the second P-type sub-limiting layer and the ohmic contact layer are kept unchanged along the thickness change, the change of the doping gas flow along with time is constant, the doping concentrations and the thicknesses of the N-type waveguide layer, the P-type waveguide layer and the first P-type sub-limiting layer all meet the quadratic function relationship, the change of the doping gas flow along with time all meets the quadratic function relationship, the power loss of the semiconductor laser is further minimized, and the performance of the semiconductor laser is improved.
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The above and other objects, features and advantages of the present disclosure will become more apparent from the following description of embodiments of the present disclosure with reference to the accompanying drawings, in which:
fig. 1 schematically illustrates an idea diagram for solving an optimal doping curve according to an embodiment of the present disclosure.
Fig. 2 schematically shows a block diagram of a low power loss semiconductor laser according to an embodiment of the present disclosure.
Fig. 3 schematically illustrates a graph of optimized doping curve piecewise fit for a low power loss target in accordance with an embodiment of the disclosure.
Fig. 4A schematically illustrates an optical field profile calculated from a refractive index profile of a semiconductor laser in an epitaxial direction and a conventional doping profile according to an embodiment of the disclosure.
Fig. 4B schematically illustrates a calculated optical field profile and a calculated optimized doping profile of a refractive index profile of a semiconductor laser in an epitaxial direction according to an embodiment of the disclosure.
Figure 5A schematically illustrates a graph of the integral of series resistance in the epitaxial direction calculated corresponding to the conventional doping of figure 4A, in accordance with an embodiment of the present disclosure.
Fig. 5B schematically illustrates a graph of the integral of the series resistance in the epitaxial direction calculated after doping optimized for low power loss corresponding to fig. 4B, in accordance with an embodiment of the disclosure.
Fig. 6A schematically illustrates a graph of the integral of the internal loss in the epitaxial direction corresponding to the conventional doping calculation of fig. 4A, in accordance with an embodiment of the present disclosure.
Fig. 6B schematically shows a graph of the integral of the calculated internal loss in the epitaxial direction after doping optimized for low power loss, corresponding to fig. 4B, in accordance with an embodiment of the present disclosure.
Fig. 7A schematically illustrates a plot of the integral of power loss in the epitaxial direction for the conventional doping calculation of fig. 4A, in accordance with an embodiment of the present disclosure.
Fig. 7B schematically shows a graph of the integral of power loss in the epitaxial direction calculated after doping optimized for low power loss corresponding to fig. 4B, in accordance with an embodiment of the disclosure.
Detailed Description
For the purpose of promoting a better understanding of the objects, aspects and advantages of the present disclosure, reference is made to the following detailed description taken in conjunction with the accompanying drawings. It is to be understood that the described embodiments are only a few, and not all, of the disclosed embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The terms "comprises," "comprising," and the like, as used herein, specify the presence of stated features, steps, operations, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, or components.
In the present disclosure, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integral; can be mechanically connected, electrically connected or can communicate with each other; either directly or indirectly through intervening media, either internally or in any other suitable relationship. The specific meaning of the above terms in the present disclosure can be understood by those of ordinary skill in the art as appropriate.
In the description of the present disclosure, it is to be understood that the terms "longitudinal," "length," "circumferential," "front," "rear," "left," "right," "top," "bottom," "inner," "outer," and the like are used in the orientation or positional relationship indicated in the drawings for convenience in describing the present disclosure and for simplicity in description, and are not intended to indicate or imply that the referenced subsystems or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present disclosure.
Throughout the drawings, like elements are represented by like or similar reference numerals. Conventional structures or constructions will be omitted when they may obscure the understanding of the present disclosure. And the shapes, sizes and positional relationships of the components in the drawings do not reflect the actual sizes, proportions and actual positional relationships. In addition, in the present disclosure, any reference signs placed between parentheses shall not be construed as limiting the present disclosure.
Similarly, in the above description of exemplary embodiments of the disclosure, various features of the disclosure are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various disclosed aspects. Reference to the description of the terms "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the disclosure. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present disclosure, "a plurality" means at least two, e.g., two, three, etc., unless explicitly defined otherwise.
In order to solve the problems in the prior art, the embodiments of the present disclosure perform further analysis and research on the relevant parameters of the semiconductor laser, which are as follows.
The series resistance of a semiconductor laser can be expressed as:
Figure BDA0003719054710000051
wherein h is the total thickness of the epitaxial layer of the semiconductor laser, q is the electron charge amount, μ (y) is the majority carrier mobility of each layer in the epitaxial direction, dop (y) is the doping concentration of each layer in the epitaxial direction (the default doping concentration is the carrier concentration), W is the stripe width of the semiconductor laser, and L is the cavity length of the semiconductor laser.
The carrier mobility of a semiconductor laser can be expressed as:
Figure BDA0003719054710000052
from this, it is understood that the mobility of carriers is related to the doping concentration, and the higher the doping concentration is, the lower the mobility is.
The internal loss of a semiconductor laser can be expressed as:
Figure BDA0003719054710000053
wherein, I j (y) is the optical field intensity in the epitaxial direction, and σ (y) is the absorption cross-sectional coefficient of the carriers in each layer in the epitaxial direction.
Absorption cross section coefficient of carrier:
Figure BDA0003719054710000061
it can be seen that the absorption cross-section coefficient of the carriers is related to the mobility, which is related to the doping concentration. The higher the doping concentration, the lower the carrier mobility and the higher the absorption cross-sectional coefficient.
The power loss of a semiconductor laser is mainly composed of joule heat loss caused by series resistance and loss caused by carrier absorption:
P loss ＝I 2 R s +P 0 Lα i
wherein I is the working current of the semiconductor laser, P 0 L is the cavity length of the semiconductor laser (irrespective of the variation of internal loss with current) for the average power in the laser cavity.
It can be seen from the above formula that the doping concentration affects the mobility, absorption cross-sectional coefficient, series resistance, and internal loss of carriers, and further affects the power loss of the semiconductor laser, so it is particularly important to select a suitable doping concentration.
Total power loss P due to direct solution loss The doping concentration dop (y) distribution function reaching the minimum is difficult, but after the epitaxial direction thickness is split, the total power loss is equal to the sum of the power losses of each split point, which can be expressed as:
P loss ＝∑p loss (j)＝∑I 2 r s (j)+P 0 Lα i (j)
P loss is a monotonically increasing function of the change in epitaxial thickness, the total power loss P loss Minimum value of (i.e. minimum power loss p per subdivision point) loss (j) The sum is added. Thus, a direct solution can be made to the total power loss P loss Converting into solving to realize power loss p of each subdivision point loss (j) The minimum doping concentration, the solving process is simplified, and the total power loss P of the semiconductor laser device can be accurately solved loss Corresponding to the minimum doping concentration.
In order to better illustrate the solution idea of the doping concentration of the semiconductor laser, the idea is better described in detail with reference to the schematic diagram of fig. 1.
Fig. 1 schematically illustrates a graph of a semiconductor laser solving for optimal doping for a low power loss target according to an embodiment of the disclosure.
As shown in fig. 1, the axis of abscissa is the thickness in the epitaxial direction, and the axis of ordinate is the power loss at each division point. The left graph shows the power loss curves corresponding to the two doping modes, where x is 0, x is h, and the area enclosed by the abscissa axis is the total power loss. When x is more than or equal to 0 and less than or equal to m, the doping mode dop 2 The power loss caused by each point is less than that of the dop mode dop 1 When m is more than x and less than or equal to h, the doping mode dop 1 The power loss caused by each point is less than that of the dop mode dop 2 . In order to realize the minimum total power loss, namely the minimum enclosed area, the dopping mode dop can be adopted by x is more than or equal to 0 and less than or equal to m 2 M is more than x and less than or equal to h, and dop is adopted 1 The implementation is realized, and the optimized doping curve is shown in the right graph. Therefore, the method can be analogized that when a plurality of doping modes exist, in order to realize the minimum total power loss, only the doping concentration with the minimum power loss at each subdivision point needs to be found, and the combined doping concentration is the optimal doping curve.
When the material and the thickness of each layer in the epitaxial direction of the semiconductor laser are determined, the optical field (Ij (y)) in the epitaxial direction is basically determined. The optical field distribution is not affected much by the doping concentration.
Therefore, based on the above analysis, the embodiment of the present disclosure divides the thickness in the epitaxial direction by the preset thickness, calculates the doping concentration that minimizes the power loss of the division point, and performs doping by using the doping concentration, thereby obtaining the semiconductor laser with low total power loss. A low-loss semiconductor laser will be described below.
Figure 2 schematically shows a block diagram of a low power loss semiconductor laser according to an embodiment of the present disclosure.
As shown in fig. 2, in the present embodiment, the low power loss semiconductor laser may include, for example: the semiconductor substrate layer 100 is sequentially stacked with an N-type confinement layer 200, an N-type waveguide layer 300, an active layer 400, a P-type waveguide layer 500, a P-type confinement layer 600 and an ohmic contact layer 700 which are epitaxial on the semiconductor substrate layer 100.
The P-type confinement layer 600 may include a first P-type sub-confinement layer 601 and a second P-type sub-confinement layer 602 stacked, the first P-type sub-confinement layer being adjacent to the P-type waveguide layer 500. In the epitaxial direction, the doping concentrations of the semiconductor substrate layer 100, the N-type confinement layer 200, the second P-type sub-confinement layer 602 and the ohmic contact layer 700 are all kept unchanged along the thickness variation, the variation of the doping gas flow along with time is a constant, the doping concentrations and the thicknesses of the N-type waveguide layer 300, the P-type waveguide layer 500 and the first P-type sub-confinement layer 601 all satisfy a quadratic function relationship, and the variation of the doping gas flow along with time satisfies a quadratic function relationship.
In an embodiment of the disclosure, the corresponding characteristic optical field intensity of the subdivision points of the N-type waveguide layer 300, the P-type waveguide layer 500 and the first P-type sub-confinement layer 601 along the epitaxial direction is greater than 10 -7 . The characteristic optical field intensity of the semiconductor substrate layer 100, the N-type confinement layer 200, the second P-type sub-confinement layer 602 and the ohmic contact layer 700 corresponding to the subdivision point along the epitaxial direction is less than 10 -7 。
In an embodiment of the present disclosure, the N-type region subdivision point characteristic light field I j (y) less than 10 -7 The region of (2 x 10) may have a uniform doping concentration 18 cm -3 For example, the doping concentrations of the semiconductor substrate layer 100 and the N-type confinement layer 200 are 2 × 10 18 cm -3 。
In an embodiment of the present disclosure, the P-type region subdivision point characteristic light field I j (y) less than 10 -7 The uniform doping concentration may be 10 19 cm -3 For example, the doping concentration of the second P-type sub-confinement layer 602 and the ohmic contact layer 700 is 10 19 cm -3 。
In an embodiment of the present disclosure, the N-type region subdivision point characteristic light field I j (y) is greater than 10 -7 Each split point having a doping concentration of 10 16 cm -3 -2*10 18 cm -3 Based on this, the doping concentration that minimizes the split point power loss is determined. For example, the N-type waveguide layer 300 may be selected to have a doping concentration of 10 at each split point 16 cm -3 -2*10 18 cm -3 Radical ofA specific quadratic dependence of the doping concentration of the N-type waveguide layer 300 on the thickness along the epitaxial thickness direction is determined. That is, the coefficients of the quadratic function satisfied by the doping concentration of the N-type waveguide layer 300 are determined by the calculated optimum doping concentration specific values.
Further, the N-type waveguide layer 300 includes a plurality of N-type sub-waveguide layers stacked one on another, and the doping concentration and the thickness of each N-type sub-waveguide layer satisfy a quadratic function relationship, and the change of the doping gas flow rate with time is a quadratic function relationship. In this embodiment, the N-type waveguide layer 300 is divided into 6 sub-waveguide layers, including: a first N type sub-waveguide layer 301, a second N type sub-waveguide layer 302, a third N type sub-waveguide layer 303, a fourth N type sub-waveguide layer 304, a fifth N type sub-waveguide layer 305, and a sixth N type sub-waveguide layer 306. The quadratic function coefficients met by the doping concentration of each N-type sub-waveguide layer are determined by the calculated specific value of the optimal doping concentration, and the quadratic function coefficients can be the same or different and can be specifically determined according to the actual application requirements.
In an embodiment of the present disclosure, the P-type region subdivision point characteristic light field I j (y) is greater than 10 -7 Each split point having a doping concentration of 10 16 cm -3 -10 19 cm -3 Based on this, the doping concentration that minimizes the split point power loss is determined. For example, the doping concentration of each split point of the P-type waveguide layer 500 and the first P-type sub-confinement layer 601 is 10 16 cm -3 -10 19 cm -3 Based on this, the specific quadratic function relationship of the doping concentration and the thickness of the P-type waveguide layer 500 and the first P-type sub-confinement layer 601 along the epitaxial thickness direction is determined. That is, the coefficients of the quadratic function satisfied by the doping concentrations of the P-type waveguide layer 500 and the first P-type sub-confinement layer 601 are determined by the calculated optimum doping concentration specific values.
In the disclosed embodiment, the active region 400 of the semiconductor laser may be generally less than 100nm thick with less overall series resistance. Since a large amount of carriers are injected into the active region, which will inevitably cause large carrier absorption, the active region is selected to be undoped in order to reduce power loss caused by the active region.
Based on the doping concentration pattern, the present embodiment provides a doping pattern for each layer of the semiconductor laser.
Fig. 3 schematically illustrates a graph of optimized doping curve piecewise fit for a low power loss target in accordance with an embodiment of the disclosure.
As shown in fig. 3, the doping concentration of each layer may be specifically as follows:
the semiconductor substrate layer 100 has a doping concentration of 2 x 10 18 cm -3 Corresponding to the source Gas Gas of the doped Gas 100 (t) the change of the flow rate with time satisfies Gas 100 (t)＝C 100 Wherein, C 100 Is a constant.
The doping concentration of the N-type confinement layer 200 is 2 x 10 18 cm -3 Corresponding to the source Gas Gas of the doped Gas 200 (t) the change of the flow rate with time satisfies Gas 200 (t)＝C 200 Wherein, C 200 Is a constant.
The doping concentration of the first N-type sub-waveguide layer 301 is obtained by fitting the calculated optimized doping function with a quadratic function:
Dop 301 (y)＝a 1 y 2 +b 1 y+c 1 corresponding to the source Gas of the doped Gas 301 (t) the change of the flow rate with time satisfies Gas 301 (t)＝A 1 t 2 +B 1 t+C 1 ；
The doping concentration of the second N-type sub-waveguide layer 302 is calculated using a quadratic function fit to obtain an optimized doping function:
Dop 302 (y)＝a 2 y 2 +b 2 y+c 2 corresponding to the source Gas Gas of the doped Gas 302 (t) the change of the flow rate with time satisfies Gas 302 (t)＝A 2 t 2 +B 2 t+C 2 ；
The doping concentration of the third N-type sub-waveguide layer 303 is obtained by fitting the calculated optimized doping function with a quadratic function:
Dop 303 (y)＝a 3 y 2 +b 3 y+c 3 corresponding to the source Gas Gas of the doped Gas 303 (t) the change of the flow rate with time satisfies Gas 303 (t)＝A 3 t 2 +B 3 t+C 3 ；
The doping concentration of the fourth N-type sub-waveguide layer 304 is obtained by fitting the calculated optimized doping function with a quadratic function:
Dop 304 (y)＝a 4 y 2 +b 4 y+c 4 corresponding to the source Gas Gas of the doped Gas 304 (t) the change of the flow rate with time satisfies Gas 304 (t)＝A 4 y 2 +B 4 y+C 4 ；
The doping concentration of the fifth N-type sub-waveguide layer 305 is obtained by fitting the calculated optimized doping function with a quadratic function:
Dop 305 (y)＝a 5 y 2 +b 5 y+c 5 corresponding to the source Gas Gas of the doped Gas 305 (t) the change of the flow rate with time satisfies Gas 305 (t)＝A 5 y 2 +B 5 y+C 5 ；
The doping concentration of the sixth N-type sub-waveguide layer 306 is obtained by fitting the calculated optimized doping function with a quadratic function:
Dop 306 (y)＝a 6 y 2 +b 6 y+c 6 corresponding to the source Gas Gas of the doped Gas 306 (t) a flow rate over time satisfies Gas 306 (t)＝A 6 y 2 +B 6 y+C 6 。
The active layer 400 is undoped.
The doping concentration of the P-type waveguide layer 500 is obtained by fitting the calculated optimized doping function with a quadratic function:
Dop 500 (y)＝a 7 y 2 +b 7 y+c 7 corresponding to the source Gas of the doped Gas 500 (t) the change of the flow rate with time satisfies Gas 500 (t)＝A 7 y 2 +B 7 y+C 7 。
The doping concentration of the first P-type sub-confinement layer 601 is obtained by fitting an optimized doping function calculated by a quadratic function:
Dop 601 (y)＝a 8 y 2 +b 8 y+c 8 corresponding to the source Gas of the doped Gas 601 (t) the change of the flow rate with time satisfies GaS 601 (t)＝A 8 y 2 +B 8 y+C 8 。
The doping concentration of the second P-type sub-confinement layer 602 is 10 19 cm -3 Corresponding to the source Gas of the doped Gas 602 (t) the change of the flow rate with time satisfies Gas 602 (t)＝C 602 。
The ohmic contact layer 700 has a doping concentration of 10 19 cm -3 Corresponding to the source Gas Gas of the doped Gas 700 (t) the change of the flow rate with time satisfies Gas 700 (t)＝C 700 。
Based on the unified inventive concept, the embodiments of the present disclosure further provide a method for manufacturing a low power loss semiconductor laser, where the method for manufacturing the low power loss semiconductor laser may include:
the semiconductor substrate layer 100 is sequentially and epitaxially stacked with an N-type confinement layer 200, an N-type waveguide layer 300, an active layer 400, a P-type waveguide layer 500, a P-type confinement layer 600 and an ohmic contact layer 700. The P-type confinement layer 600 includes a first P-type sub-confinement layer 601 and a second P-type sub-confinement layer 602 stacked on top of each other, and the first P-type sub-confinement layer is close to the P-type waveguide layer 500.
In the epitaxial process, along the epitaxial direction, the doping concentrations of the semiconductor substrate layer 100, the N-type confinement layer 200, the second P-type confinement sub-layer 602 and the ohmic contact layer 700 are all kept unchanged along the thickness variation, the variation of the doping gas flow along with time is a constant, the doping concentrations and the thicknesses of the N-type waveguide layer 300, the P-type waveguide layer 500 and the first P-type confinement sub-layer 601 all satisfy a quadratic function relationship, and the variation of the doping gas flow along with time all satisfy the quadratic function relationship.
It should be noted that, parts of the method embodiment that are not described in detail are similar to or identical to parts of the device embodiment, and specific reference is made to the parts of the device embodiment, which are not described herein again.
In order to further verify that the low power consumption semiconductor laser device provided by the embodiment of the present disclosure has low power consumption, the embodiment of the present disclosure also provides some experimental data for proving.
Fig. 4A schematically illustrates an optical field profile calculated from a refractive index profile of a semiconductor laser in an epitaxial direction and a conventional doping profile according to an embodiment of the disclosure.
Fig. 4B schematically illustrates a calculated optical field profile and a calculated optimized doping profile for a refractive index profile of a semiconductor laser in the epitaxial direction according to an embodiment of the disclosure.
Figure 5A schematically illustrates a graph of the integral of series resistance in the epitaxial direction calculated corresponding to the conventional doping of figure 4A, in accordance with an embodiment of the present disclosure.
Fig. 5B schematically illustrates a graph of the integral of the series resistance in the epitaxial direction calculated after doping optimized for low power loss corresponding to fig. 4B, in accordance with an embodiment of the disclosure.
As shown in fig. 4A-5B, based on conventional doping, the total resistance of the semiconductor laser is 15.98m Ω, and with the optimized doping method, the total resistance of the semiconductor laser is 6.35m Ω, and after doping optimization, the series resistance of the semiconductor laser is reduced by 9.63m Ω.
Fig. 6A schematically illustrates a graph of the integral of the internal loss in the epitaxial direction corresponding to the conventional doping calculation of fig. 4A, in accordance with an embodiment of the present disclosure.
Fig. 6B schematically shows a graph of the integral of the calculated internal loss in the epitaxial direction after doping optimized for low power loss, corresponding to fig. 4B, in accordance with an embodiment of the present disclosure.
As shown in FIGS. 6A-6B, the total internal loss of the semiconductor laser is 0.39cm based on conventional doping -1 The total internal loss of the semiconductor laser is 0.57cm by adopting the optimized doping mode -1 After the doping optimization, the internal loss of the semiconductor laser is increased by 0.18cm -1 。
Fig. 7A schematically illustrates a graph of the integral of power loss in the epitaxial direction corresponding to the conventional doping calculation of fig. 4A, in accordance with an embodiment of the present disclosure.
Fig. 7B schematically shows a graph of the integral of power loss in the epitaxial direction calculated after doping optimized for low power loss corresponding to fig. 4B, in accordance with an embodiment of the disclosure.
As shown in fig. 7A-7B, the total power loss of the semiconductor laser is 7.95W based on the conventional doping, and the total power loss of the semiconductor laser is 4.82W by using the optimized doping method, which is reduced by 3.13W after the doping optimization.
Electro-optical conversion efficiency of semiconductor laser:
Figure BDA0003719054710000111
wherein eta is i For internal quantum efficiency, alpha m For surface loss of cavity, U 0 To turn on the voltage, I th Is the threshold current. Substituting various parameters of the semiconductor structure of the embodiment of the disclosure into the formula, and calculating the electro-optic conversion efficiency of the semiconductor laser to be 67% at a current of 20A when the conventional doping curve corresponding to FIG. 4A is adopted; when the optimized doping curve corresponding to fig. 4B is adopted, the electro-optic conversion efficiency of the semiconductor laser is calculated to be 73% at a current of 20A. After doping optimization, the electro-optic conversion efficiency of the semiconductor laser is increased by 6%.
To sum up, in the low power semiconductor laser device provided by the embodiment of the present disclosure, each layer of the semiconductor laser is split along the epitaxial direction, and an appropriate doping concentration is selected at each split point, so that the doping concentrations of the semiconductor substrate layer, the N-type confinement layer, the second P-type sub-confinement layer and the ohmic contact layer are all kept unchanged along the thickness variation, the doping gas flow rate is constant along with the time variation, the doping concentrations and the thicknesses of the N-type waveguide layer, the P-type waveguide layer and the first P-type sub-confinement layer all satisfy the quadratic function relationship, and the doping gas flow rate all satisfies the quadratic function relationship along with the time variation, thereby minimizing the power loss of the semiconductor laser and improving the performance of the semiconductor laser.
The above-mentioned embodiments are intended to illustrate the objects, aspects and advantages of the present disclosure in further detail, and it should be understood that the above-mentioned embodiments are only illustrative of the present disclosure and are not intended to limit the present disclosure, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present disclosure should be included in the scope of the present disclosure.

Claims (10)

1. A low power loss semiconductor laser, comprising:
the waveguide structure comprises a semiconductor substrate layer (100), and an N-type limiting layer (200), an N-type waveguide layer (300), an active layer (400), a P-type waveguide layer (500), a P-type limiting layer (600) and an ohmic contact layer (700) which are sequentially stacked and extended on the semiconductor substrate layer (100); the P-type limiting layer (600) comprises a first P-type sub-limiting layer (601) and a second P-type sub-limiting layer (602) which are stacked, and the first P-type sub-limiting layer (601) is close to the P-type waveguide layer (500);
along the epitaxial direction, the doping concentrations of the semiconductor substrate layer (100), the N-type limiting layer (200), the second P-type sub-limiting layer (602) and the ohmic contact layer (700) are kept unchanged along the thickness change, the change of the doping gas flow along with time is a constant, the doping concentrations and the thicknesses of the N-type waveguide layer (300), the P-type waveguide layer (500) and the first P-type sub-limiting layer (601) all satisfy a quadratic function relationship, and the change of the doping gas flow along with time satisfies a quadratic function relationship.
2. Low power loss semiconductor laser according to claim 1, characterized in that the doping concentration of the semiconductor substrate layer (100) and the N-type confinement layer (200) is 2 x 10 in the epitaxial direction 18 cm -3 。
3. A low power loss semiconductor laser as claimed in claim 1 wherein the doping concentration of the second P-type sub-confinement layer (602) and the ohmic contact layer (700) is 10 along the epitaxial direction 19 cm -3 。
4. A low power loss semiconductor laser as claimed in claim 1 wherein the corresponding characteristic optical field intensity of the splitting point of the N-type waveguide layer (300), the P-type waveguide layer (500) and the first P-type sub-confinement layer (601) along the epitaxial direction is greater than 10 -7 。
5. A low power loss semiconductor laser as claimed in claim 1, wherein the semiconductor substrate layer (100),The characteristic optical field intensity corresponding to the subdivision points of the N-type confinement layer (200), the second P-type sub-confinement layer (602) and the ohmic contact layer (700) along the epitaxial direction is less than 10 -7 。
6. A low power loss semiconductor laser as claimed in claim 1, wherein the active layer (400) is undoped.
7. A low power lossy semiconductor laser according to claim 1, wherein the quadratic dependence of the variation with time of the doping gas flow of the N-type waveguide layer (300), the P-type waveguide layer (500) and the first P-type sub-confinement layer (601) is determined by the doping concentration and the growth rate of the corresponding layers.
8. A low power loss semiconductor laser as claimed in claim 1 wherein the N-type waveguide layer (300) comprises a stack of N-type sub-waveguide layers, each N-type sub-waveguide layer having a doping concentration and a thickness that satisfy a quadratic relationship, the flow of the doping gas varying with time as a function of time.
9. A low power loss semiconductor laser as claimed in claim 1, wherein the thickness of the active layer (400) is less than 100 nm.
10. A method for fabricating a low power loss semiconductor laser, comprising:
the semiconductor substrate layer (100) is sequentially and epitaxially laminated with an N-type limiting layer (200), an N-type waveguide layer (300), an active layer (400), a P-type waveguide layer (500), a P-type limiting layer (600) and an ohmic contact layer (700); the P-type confinement layer (600) comprises a first P-type sub-confinement layer (601) and a second P-type sub-confinement layer (602) which are stacked, and the first P-type sub-confinement layer (601) is close to the P-type waveguide layer (500);
in the epitaxial process, along the epitaxial direction, the doping concentrations of the semiconductor substrate layer (100), the N-type limiting layer (200), the second P-type sub-limiting layer (602) and the ohmic contact layer (700) are kept unchanged along the thickness change, the change of the doping gas flow along with time is a constant, the doping concentrations and the thicknesses of the N-type waveguide layer (300), the P-type waveguide layer (500) and the first P-type sub-limiting layer (601) all meet the quadratic function relationship, and the change of the doping gas flow along with time all meets the quadratic function relationship.
CN202210754306.0A 2022-06-28 2022-06-28 Low-power-loss semiconductor laser and preparation method thereof Pending CN115133403A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116937331A (en) * 2023-09-15 2023-10-24 材料科学姑苏实验室 Semiconductor laser and preparation method thereof
CN117175347A (en) * 2023-09-01 2023-12-05 安徽格恩半导体有限公司 Semiconductor laser

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117175347A (en) * 2023-09-01 2023-12-05 安徽格恩半导体有限公司 Semiconductor laser
CN117175347B (en) * 2023-09-01 2024-04-26 安徽格恩半导体有限公司 Semiconductor laser
CN116937331A (en) * 2023-09-15 2023-10-24 材料科学姑苏实验室 Semiconductor laser and preparation method thereof
CN116937331B (en) * 2023-09-15 2023-12-12 材料科学姑苏实验室 Semiconductor laser and preparation method thereof

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