Isochronal transient superposition method and apparatus for photogenerated carrier field distribution

Abstract

The present disclosure provides a method and device for isochronous transient superposition of photogenerated carrier field distribution, which can be applied to the fields of silicon-based optoelectronic technology and photoelectric detection technology. The method comprises: discretizing the motion duration of photogenerated carriers in the intrinsic absorption region of a material to obtain a discrete slice family; iteratively determining the photogenerated carrier distribution information of each discrete slice in the discrete slice family one by one until the photogenerated carriers in all discrete slices in the discrete slice family are completely swept out by the electric field; and superimposing the photogenerated carrier distribution information at any first target position in the intrinsic absorption region of the material to obtain target field distribution information of the photogenerated carriers.

Description

Technical Field

[0001] This disclosure relates to the fields of silicon-based optoelectronic technology and photoelectric detection technology, and in particular to an isochronous transient superposition method and apparatus for photogenerated carrier field distribution. Background Technology

[0002] The actual growth of materials often differs from the simulated growth, which can lead to uneven material composition distribution or gradual changes in the material growth interface during the growth process. For devices composed of materials exhibiting such phenomena, relevant technologies generally employ field simulation or introduce differential equations to determine the field distribution of photogenerated carriers in such devices.

[0003] The field simulation techniques of related technologies oversimplify the handling of photogenerated carrier properties, making it difficult to interpret and control the state of photogenerated carriers in devices. Furthermore, the methods used in these techniques to determine photogenerated carriers using differential equations introduce significant complexity and computational time due to the need to solve these equations. Overall, because these techniques struggle to efficiently and easily determine the distribution of photogenerated carriers in materials exhibiting the aforementioned phenomena, it is difficult to provide feedback and adjustments to the simulation results, leading to low simulation efficiency and inaccurate simulation results. Therefore, there is a need for a method that can easily and quickly determine the distribution of photogenerated carriers in materials exhibiting this phenomenon, thereby improving the accuracy of material simulation results. Summary of the Invention

[0004] In view of the above problems, this disclosure provides an isochronous transient superposition method and apparatus for determining the photogenerated carrier field distribution in a non-uniform material.

[0005] One aspect of this disclosure provides an isochronous transient superposition method for the field distribution of photogenerated carriers, comprising: discretizing the motion time of photogenerated carriers in the intrinsic absorption region of a material to obtain a family of discrete slices; iteratively determining the photogenerated carrier distribution information of each discrete slice in the family of discrete slices until the photogenerated carriers in all discrete slices of the family of discrete slices are completely swept out by the electric field; and superimposing the photogenerated carrier distribution information at any first target location in the intrinsic absorption region of the material to obtain the target field distribution information of the photogenerated carriers.

[0006] According to embodiments of this disclosure, the discrete slices have discrete time periods; the iterative determination of the photogenerated carrier distribution information of each discrete slice in the discrete slice family includes: determining the generation rate information and recombination rate information of the photogenerated carriers in absolute coordinates; and calculating the photogenerated carrier distribution information of the discrete slices in absolute coordinates based on the generation rate information in absolute coordinates, the recombination rate information of the photogenerated carriers, and the discrete time periods of the discrete slices.

[0007] According to embodiments of this disclosure, the method further includes: obtaining the absolute starting position coordinates of the discrete slice in the absolute coordinates; performing coordinate transformation on the absolute starting position coordinates according to the relative coordinates and the relative coordinate vector in the absolute coordinates to obtain the relative starting position coordinates of the discrete slice in the relative coordinates; constructing the generation rate information and recombination rate information of the photogenerated carriers in the relative coordinates based on the relative starting position coordinates; and calculating the photogenerated carrier distribution information of the discrete slice in the relative coordinates based on the generation rate information, the recombination rate information of the photogenerated carriers, and the discrete time period of the discrete slice.

[0008] According to an embodiment of this disclosure, the superposition of the photogenerated carrier distribution information at the first target location includes: calling a superposition function for photogenerated carriers; determining a discrete slice at the first target location; inputting the photogenerated carrier distribution information of the discrete slice into the superposition function; and outputting the target field distribution information of the photogenerated carriers.

[0009] According to embodiments of this disclosure, the discrete slices include photogenerated carrier line density information; the method further includes: irradiating any discrete slices in the family of discrete slices with pulsed light to change the photogenerated carrier line density information and the shape of the discrete slices by the pulsed light, wherein the discrete slices irradiated by the pulsed light are designated as irradiated slices; determining the photogenerated carrier distribution information of the irradiated slices based on the changed photogenerated carrier line density information and the shape of the discrete slices; and constructing a photogenerated carrier field distribution model under the pulsed light irradiation condition based on the photogenerated carrier distribution information of the irradiated slices.

[0010] According to an embodiment of this disclosure, the method further includes: determining a set of target locations in the intrinsic absorption region of the material where continuous light irradiation occurs; and for all second target locations in the set of target locations, superimposing the photogenerated carrier distribution information at each of the second target locations to obtain a photogenerated carrier field distribution model under continuous light irradiation.

[0011] According to embodiments of this disclosure, the method further includes: obtaining a family of damped discrete slices by applying damping to the velocity of the photogenerated carriers; iteratively determining the photogenerated carrier distribution information of each damped discrete slice in the family of damped discrete slices until the photogenerated carriers of all damped discrete slices in the family of damped discrete slices are completely swept out by the electric field; and superimposing the photogenerated carrier analysis information of the damped discrete slices at any third target location in the intrinsic absorption region to construct a photogenerated carrier field distribution model under damping conditions.

[0012] According to an embodiment of this disclosure, the method further includes: sequentially removing the photogenerated carrier distribution information of the discrete slice from the target field distribution information of the photogenerated carriers to construct a photogenerated carrier field distribution model under illumination-off conditions.

[0013] According to embodiments of this disclosure, the shape of the discrete slice is related to the type of material, and the shape of the discrete slice includes at least one of the following: a smooth curve shape for a material with graded composition, a step shape for a stepped material, and a serrated shape for a quantum well material.

[0014] Another aspect of this disclosure provides an isochronous transient superposition device for the field distribution of photogenerated carriers, comprising: a discretization module for discretizing the motion time of photogenerated carriers in the intrinsic absorption region of a material to obtain a family of discrete slices; a first iteration module for iteratively determining the photogenerated carrier distribution information of each discrete slice in the family of discrete slices until the photogenerated carriers of the last discrete slice in the family of discrete slices are completely swept out by the electric field; and a first superposition module for superimposing the photogenerated carrier distribution information at any first target location in the intrinsic absorption region to obtain the target field distribution information of the photogenerated carriers.

[0015] According to the isochronous transient superposition method and apparatus for photogenerated carrier field distribution provided in this disclosure, the motion time of photogenerated carriers in the intrinsic absorption region of the material is discretized to obtain a family of discrete slices; the photogenerated carrier distribution information of each discrete slice in the family of discrete slices is determined iteratively until the photogenerated carriers of all discrete slices in the family of discrete slices are completely swept out by the electric field; at any first target position in the intrinsic absorption region of the material, the photogenerated carrier distribution information at the first target position is superimposed to obtain the target field distribution information of photogenerated carriers. Since the motion time of photogenerated carriers is discretized and the photogenerated carrier distribution information of each discrete slice is determined in the process of determining the photogenerated carrier field distribution information, when it is necessary to determine the photogenerated carrier field distribution at any target position, the photogenerated carrier distribution information of the discrete slices at that target position can be superimposed to eliminate the time process of extracting carriers when the material composition distribution is not uniform, and the method can obtain the field distribution information of photogenerated carriers without solving a system of differential equations, thus avoiding the time consumption of solving a system of differential equations. This method is relatively simple and at least partially overcomes the problem of difficulty in efficiently and easily determining the distribution of photogenerated carriers in materials in related technologies. It can efficiently and easily determine the field distribution information of photogenerated carriers under the phenomena of uneven material composition distribution or gradual changes in the material growth interface. This can provide more accurate feedback and debugging for the simulation of device materials, thereby improving the simulation efficiency and accuracy of material simulation results. Attached Figure Description

[0016] The foregoing contents, as well as other objects, features, and advantages of this disclosure, will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0017] Figure 1 A flowchart illustrating an isochronous transient superposition method for photogenerated carrier field distribution according to an embodiment of the present disclosure is schematically shown.

[0018] Figure 2 A schematic diagram illustrating the shape of a discrete slice according to an embodiment of the present disclosure is shown.

[0019] Figure 3 A schematic diagram of a timing transient superposition algorithm according to an embodiment of the present disclosure is shown;

[0020] Figure 4A A schematic diagram illustrating the superposition process according to an embodiment of the present disclosure is shown.

[0021] Figure 4B The illustration shows a schematic diagram of the overlay using a script according to an embodiment of the present disclosure;

[0022] Figure 5AA schematic diagram illustrating the target field distribution information of photogenerated carriers according to an embodiment of the present disclosure is shown.

[0023] Figure 5B A schematic diagram illustrating the target field distribution information of photogenerated carriers according to another embodiment of this disclosure is shown; and

[0024] Figure 6 A schematic block diagram of an isochronous transient superposition device for photogenerated carrier field distribution according to an embodiment of the present disclosure is shown. Detailed Implementation

[0025] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0026] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0027] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0028] When using expressions such as "at least one of A, B, and C", they should generally be interpreted in accordance with the meaning that is commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B, and C, etc.).

[0029] In the technical solution disclosed herein, the user information (including but not limited to user personal information, user image information, user device information, such as location information) and data (including but not limited to data used for analysis, stored data, and displayed data) involved are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, storage, use, processing, transmission, provision, disclosure, and application of the relevant data all comply with the relevant laws, regulations, and standards of the relevant countries and regions, necessary confidentiality measures have been taken, and they do not violate public order and good morals. Corresponding operation entry points are provided for users to choose to authorize or refuse.

[0030] Because the actual growth results of materials often differ from the simulation design results, and because the actual growth process frequently involves gradual interface changes and material inhomogeneity, this poses significant challenges to engineering debugging in common field simulation schemes. Furthermore, common field simulations oversimplify the handling of photogenerated carrier properties, making it difficult to interpret and debug the state of photogenerated carriers in devices containing that material. Deviating from field simulation and using discretized differential equations to model inhomogeneous materials introduces enormous complexity.

[0031] In view of this, embodiments of this disclosure propose a method of extracting photogenerated carriers by performing stationary-state slicing and then superimposing the slices. Based on observation and modeling of slices for each time period, the distribution of photogenerated carriers can be well simulated. By discretizing in time and then superimposing the stationary-state slices, the time process of non-uniformly distributed extracted carriers is eliminated. Based on the deformation of the stationary-state slices, it can be used to simulate the high saturation phenomenon of photogenerated carriers. Therefore, for the change in field distribution after superposition, only the information of the slices needs to be processed to approximately estimate the carrier transport phenomenon. The method of embodiments of this disclosure does not require solving differential equations, thereby reducing computation time. The simplicity and low computation time of this method can improve the efficiency and accuracy of simulation. Furthermore, by appropriately modifying this method, photogenerated carrier distribution models under conditions such as pulsed light irradiation, continuous light irradiation, large light irradiation conditions, and off-conditions can also be constructed. The method of embodiments of this disclosure and the photogenerated carrier distribution models under various modified conditions will be described in detail below.

[0032] Figure 1 A flowchart illustrating an isochronous transient superposition method for photogenerated carrier field distributions according to an embodiment of the present disclosure is shown schematically.

[0033] like Figure 1 As shown, the isochronous transient superposition method for the photogenerated carrier field distribution in this embodiment may include operations S110 to S130.

[0034] In operation S110, the motion time of photogenerated carriers in the intrinsic absorption region of the material is discretized to obtain a family of discrete slices.

[0035] In operation S120, the photogenerated carrier distribution information of each discrete slice in the discrete slice family is determined iteratively until the photogenerated carriers of all discrete slices in the discrete slice family are completely swept out by the electric field.

[0036] In operation S130, at any first target location in the intrinsic absorption region of the material, the distribution information of photogenerated carriers at the first target location is superimposed to obtain the target field distribution information of photogenerated carriers.

[0037] According to embodiments of this disclosure, the motion duration can be represented by T, and the value of T should be greater than the longest motion duration of photogenerated carriers. When discretizing the motion duration T, the motion duration can be discretized as finely as possible, so that the number N of discrete slices in the discrete slice family is sufficiently large. Optionally, discretizing the motion duration sufficiently finely can mean that the discrete time periods represented by multiple discrete slices can achieve an approximately continuous state.

[0038] Optionally, each discrete slice in the discrete slice family can be numbered, for example, sequentially numbered 1, 2, 3, ..., N.

[0039] Figure 2 A schematic diagram of the shape of a discrete slice according to an embodiment of the present disclosure is shown.

[0040] Figure 2 The absolute coordinates are shown. Information about a discrete slice can include two parts: one part can be the slice's own properties, which can include the physical scale and the linear density of photogenerated carriers, for example... Figure 2 In the relative coordinate system, the x-axis represents the defined physical scale, and the y-axis represents the linear density of photogenerated carriers. Another portion of the information in the discrete slice can be properties of relative motion, such as velocity, acceleration, and the starting coordinate A in absolute coordinates. i End point coordinates B i The dynamic quantities of charge carriers are related to the electric field they are in, and the electric field distribution can be E(x).

[0041] According to embodiments of this disclosure, the acquisition of discrete slices is closely related to the absorption coefficient distribution of the material. For example, if the absorption coefficient of the material is large at a certain location, the photogenerated carrier density at that location on the discrete slice will be high. Initially, the physical scale of the discrete slice is consistent with the scale of the intrinsic absorption region of the material.

[0042] Optionally, the size of the photogenerated carriers in the x-direction can be expressed as d. iThis means that i can be equal to 1, 2, 3, ..., N.

[0043] According to embodiments of this disclosure, the parameters of the stationary slice can be varied, and the specific influencing factors of the relevant parameters are as follows.

[0044] The physical scale in its own properties, its size d i The degree of obstruction can vary depending on the discrete time point. For example, where photogenerated carriers accumulate, the electric field is insufficient to drive the movement of the slice, causing carrier obstruction. This obstruction will lead to a decrease in the size d. i The shorter the slice, the greater the degree of blockage, and the greater the shortening. Meanwhile, the number of photogenerated carriers in a discrete slice is constant, but if the slice moves to a point where there is an increase (avalanche) or decrease (non-radiative recombination) in photogenerated carriers, this will cause the linear carrier density on the discrete slice to decrease at that point.

[0045] The changes in the absolute properties of a stationary slice are mainly affected by empirical parameters of the test, such as the material mobility. The initial coordinate values ​​are related to the observation time of the slice, and the final coordinates are the starting coordinates plus the physical scale in its own properties. The acceleration is related to the electric field in the system.

[0046] The linear density of photogenerated carriers is related to the absorption coefficient of the material and the light power at that point. Higher light power and a larger absorption coefficient result in a higher density of photogenerated carriers at that point. The density of photogenerated carriers is also related to the duration of the time represented by the stationary state slice.

[0047] Optional, Figure 2 The schematic relative coordinates can be used in the subsequent coordinate transformation process, as well as to solve for the photogenerated carrier distribution information after the coordinate transformation process.

[0048] According to embodiments of this disclosure, the shape of the discrete slice is related to the type of material. Specifically, the shape of the discrete slice may include at least one of the following: a smooth curve shape for a material with graded composition, a step shape for a stepped material, and a serrated shape for a quantum well material, etc.

[0049] Optionally, as described above, the number of discrete slices N can be large enough. However, a large number of discrete slices N may result in different photogenerated carrier densities for the discrete time periods represented by the discrete slices. Furthermore, the initial velocities of the carriers in each slice are the same, but the dynamic parameters are different. Therefore, the state of each discrete slice needs to be iteratively calculated for each photogenerated carrier distribution information until the last slice of the carrier distribution map is completely removed (the carriers are completely swept out by the electric field).

[0050] According to the embodiments of this disclosure, after the photogenerated carrier distribution information of all discrete slices has been calculated, the time variable is eliminated in the superposition of each discrete slice. By superimposing and solving for each observation position (any first target position), the target field distribution information of photogenerated carriers can be obtained.

[0051] In general, after obtaining the light absorption coefficient of the material, the shape of the slice under uniform illumination can be plotted. After slicing the motion time of the photogenerated carriers (each slice is called a stationary discrete slice), the position and velocity of the photogenerated carrier distribution map of each discrete slice are calculated and analyzed, iterating one by one until the last carrier distribution map slice is completely removed (the carriers are completely swept out by the electric field). The information of the corresponding discrete slices in the discrete slices at each time observation position is superimposed to calculate the target field distribution information of photocarriers under small signal (low power, such as less than 10mW).

[0052] According to the isochronous transient superposition method and apparatus for photogenerated carrier field distribution provided in this disclosure, the motion time of photogenerated carriers in the intrinsic absorption region of the material is discretized to obtain a family of discrete slices; the photogenerated carrier distribution information of each discrete slice in the family of discrete slices is determined iteratively until the photogenerated carriers of all discrete slices in the family of discrete slices are completely swept out by the electric field; at any first target position in the intrinsic absorption region of the material, the photogenerated carrier distribution information at the first target position is superimposed to obtain the target field distribution information of photogenerated carriers. Since the motion time of photogenerated carriers is discretized and the photogenerated carrier distribution information of each discrete slice is determined in the process of determining the photogenerated carrier field distribution information, when the photogenerated carrier field distribution at any target position is required, the photogenerated carrier information distribution information of the discrete slice at the target position can be superimposed to eliminate the time process of extracting carriers when the material composition distribution is uneven, and the method can obtain the field distribution information of photogenerated carriers without solving a system of differential equations, thus avoiding the time consumption of solving a system of differential equations. This method is relatively simple and at least partially overcomes the problem of difficulty in efficiently and easily determining the distribution of photogenerated carriers in materials in related technologies. It can efficiently and easily determine the field distribution information of photogenerated carriers under the phenomena of uneven material composition distribution or gradual changes in the material growth interface. This can provide more accurate feedback and debugging for the simulation of device materials, thereby improving the simulation efficiency and accuracy of material simulation results.

[0053] According to embodiments of this disclosure, the discrete time intervals of the discrete slices described above can be Δ1, Δ2, Δ3, ..., Δ... NThis indicates that operation S120 may include the following operations: determining the generation rate information and recombination rate information of photogenerated carriers in absolute coordinates; and calculating the photogenerated carrier distribution information of the discrete slice in absolute coordinates based on the generation rate information in absolute coordinates, the recombination rate information of photogenerated carriers, and the discrete time period of the discrete slice.

[0054] According to embodiments of this disclosure, the generation rate information of photogenerated carriers can be represented by G(x), and the coincidence rate information of photogenerated carriers can be represented by R(x). Both G(x) and R(x) can be determined using related techniques.

[0055] Taking the i-th discrete slice as the analysis object, its represented discrete time period is Δ. i The carrier distribution information in a discrete slice in absolute coordinates can be represented by Y. i (x)=[G(x)+R(x)]·Δ i .

[0056] Alternatively, in addition to calculating the carrier distribution information in absolute coordinates, we can also calculate the carrier distribution information in relative coordinates.

[0057] For example, obtain the absolute starting position coordinates of the discrete slice in absolute coordinates; perform coordinate transformation on the absolute starting position coordinates according to the relative coordinate vectors in relative coordinates and absolute coordinates to obtain the relative starting position coordinates of the discrete slice in relative coordinates; construct the generation rate information and recombination rate information of photogenerated carriers in relative coordinates based on the relative starting position coordinates; calculate the distribution information of photogenerated carriers of the discrete slice in relative coordinates based on the generation rate information, the recombination rate information of photogenerated carriers, and the discrete time period of the discrete slice.

[0058] According to embodiments of this disclosure, the relative coordinate variable relative to the absolute coordinate can be l, and this relative coordinate vector is used to determine the absolute starting position coordinates (A). i After performing a coordinate transformation, we can obtain x = l + A i , which serves as the relative starting position coordinate of the discrete slice in the relative coordinate system.

[0059] The generation rate information of photogenerated carriers in relative coordinates can be constructed based on the relative initial position coordinates, which can be G(l+A). i The constructed composite rate information can be R(l+A) i )

[0060] Based on the generation rate information in the relative coordinates, the recombination rate information of photogenerated carriers, and the discrete time interval of the discrete slice, Y can be obtained. i (x)=[G(l+A i )+R(l+Ai )]·Δ i This serves as information on the distribution of photogenerated carriers in relative coordinates for a discrete slice.

[0061] Alternatively, the velocity of photogenerated carriers can be calculated using dynamic methods, such as by... We obtain, where v0 can be the initial velocity of the photogenerated carriers, n is the number of discrete slices, and Δ n Let be the discrete time interval of the nth discrete slice, and a be the acceleration of the photogenerated carriers.

[0062] Alternatively, the velocity of photogenerated carriers can also be calculated using the law of conservation of energy, for example, by... Where, m * Let v be the equivalent mass of the photogenerated carrier, v0 be the initial velocity of the photogenerated carrier, x0 be the initial position of the photogenerated carrier, v be the velocity of the photogenerated carrier reaching position x, E(x) be the electric field strength, and q be the charge. By solving for the velocity of the photogenerated carrier, any first target position in the intrinsic region of the material can be determined, thereby obtaining the target field distribution information of the photogenerated carrier at that first target position.

[0063] Optionally, the distribution information of photogenerated carriers on discrete slices can be calculated one by one. These discrete slices are the equivalent states of photogenerated carriers observed over time in each time period. At any first position, the distribution information of photogenerated carriers on the corresponding discrete slices at that position can be superimposed to obtain the target field distribution information of photogenerated carriers at that first position.

[0064] Optionally, obtaining the target field distribution information of photogenerated carriers at the first location may include the following operations: calling the superposition function of photogenerated carriers; determining the discrete slice at the first target location; inputting the photogenerated carrier distribution information of the discrete slice into the superposition function, and outputting the target field distribution information of photogenerated carriers.

[0065] The superposition function is, for example: Where n is the number of discrete slices, n can be equal to 1, 2, 3, ..., N. By using each Y at the first target position... n (x) can be input into the superposition function to obtain the target field distribution information of photogenerated carriers at the first target location.

[0066] Optionally, the process of determining the photogenerated carrier field distribution information has already been described in the morning. The following will describe the photogenerated carrier distribution model under various deformation conditions.

[0067] For a model of the photogenerated carrier field distribution under pulsed light illumination, each discrete slice represents the evolution of the initial state of the photogenerated carriers over a certain period of time. Observing the slices sequentially provides a silhouette of the photogenerated carriers transiting through the absorption region. Therefore, the family of stationary slices forms the path of the photogenerated carrier transit states along the time axis. Thus, changing the photogenerated carrier linear density information and the shape of any discrete slice along the path can represent the influence of carrier states at different positions and times. Therefore, by considering each discrete slice separately, the device can be modeled under pulsed light illumination.

[0068] Optionally, based on the above operations, constructing a photogenerated carrier field distribution model under pulsed light illumination can include the following operations: illuminating any discrete slice in the discrete slice family with pulsed light to change the photogenerated carrier linear density information and the shape of the discrete slice through the pulsed light, wherein the discrete slice illuminating the pulsed light is called the illuminating slice; determining the photogenerated carrier distribution information of the illuminating slice based on the changed photogenerated carrier linear density information and the shape of the discrete slice; and constructing a photogenerated carrier field distribution model under pulsed light illumination based on the photogenerated carrier distribution information of the illuminating slice.

[0069] According to embodiments of this disclosure, the process of determining the photogenerated carrier distribution information of the irradiated slice based on the altered photogenerated carrier linear density information and the shape of the discrete slice can also employ the same iterative process as operation S120; the process of superimposing the photogenerated carrier information of the irradiated slice can employ the same superposition process as operation S130.

[0070] For the photogenerated carrier field distribution model under continuous illumination, we can view the discrete slice family holistically. This involves extracting and superimposing the photogenerated carrier distribution information at each location, transforming the time-varying calculus problem into a time-dependent path problem. This allows us to model the device under continuous illumination.

[0071] Optionally, based on the above operations, constructing a photogenerated carrier field distribution model under continuous illumination may include the following operations: determining a set of target locations in the intrinsic absorption region of the material where continuous illumination exists; for all second target locations in the target location set, superimposing the photogenerated carrier distribution information at each second target location to obtain a photogenerated carrier field distribution model under continuous illumination.

[0072] According to embodiments of this disclosure, the process of superimposing the photogenerated carrier distribution information at the second target location can employ the same superposition process as operation S130.

[0073] For the damped photogenerated carrier field distribution model, the congestion phenomenon of photogenerated carriers can be approximated by applying damping to the velocity. Alternatively, the stable field distribution of carriers after timed transient superposition can be iterated for each discrete slice, with each subsequent field distribution influenced by the previous one, gradually finding the state of the field distribution to model the device under congestion conditions. Optionally, since high illumination (e.g., illumination greater than 10mW) generally leads to photogenerated carrier congestion, the modeling under congestion conditions can also be modeling under high illumination conditions.

[0074] Optionally, based on the above operations, constructing a photogenerated carrier field distribution model under damping conditions may include the following operations: obtaining a family of damped discrete slices by applying damping to the velocity of the photogenerated carriers; iteratively determining the photogenerated carrier distribution information of each damped discrete slice in the family of damped discrete slices until the photogenerated carriers of all damped discrete slices in the family of damped discrete slices are completely swept out by the electric field; and superimposing the photogenerated carrier analysis information of the damped discrete slices at any third target position in the intrinsic absorption region to construct a photogenerated carrier field distribution model under damping conditions.

[0075] According to embodiments of this disclosure, the process of iteratively determining the photogenerated carrier distribution information of each damped discrete slice in the damped discrete slice family can refer to the iterative process of operation S120; the process of superimposing the photogenerated carrier analysis information of the damped discrete slice at the third target position can refer to the superposition process of operation S130.

[0076] According to embodiments of this disclosure, the first target position, the second target position, and the third target position can all refer to the same or different positions. The terms "first," "second," and "third" are merely to distinguish positions under different conditions. For example, the first target position can be a position that does not require a specific scenario, the second target position can be a position that requires continuous illumination, and the third target position can be a position that requires damping.

[0077] For the photogenerated carrier field distribution model under illumination-off conditions, the field distribution after discrete slice stacking or after iteration is sequentially stripped of the discrete slices. By subtracting elements, we can model the device under conditions where illumination is off.

[0078] Optionally, based on the above operations, constructing a photogenerated carrier field distribution model under illumination-off conditions may include the following operations: sequentially removing the photogenerated carrier distribution information of discrete slices from the target field distribution information of photogenerated carriers to construct a photogenerated carrier field distribution model under illumination-off conditions. For example, for... Figure 3In the fourth observation period, the photogenerated carrier distribution information of the discrete slices can be removed sequentially from left to right to obtain the photogenerated carrier field distribution information under the condition of illumination off.

[0079] According to embodiments of this disclosure, by applying different operations to discrete slices, photogenerated carrier field distribution models under pulsed light irradiation, continuous light irradiation, heavy light irradiation, and light-off conditions can be obtained respectively. This method is not only simple, but also improves the diversity of information on the distribution of photogenerated carrier fields.

[0080] To illustrate, the following embodiment will be used to further describe the isochronous transient superposition method of the above-mentioned photogenerated carrier field distribution.

[0081] This embodiment can be configured with the following prerequisites:

[0082] Under continuous illumination, the light field is stable and the electro-optic conversion of the device is stable. Time is uniformly discretized (each discrete slice represents the same time period), and the center point of each time period is equivalent to the time of a discrete slice, named the observation time period of that discrete slice. Under low illumination conditions, it is assumed that no congestion occurs, and only the distribution of charge carriers is considered. A uniform electric field approximation is used, the absorption region is intrinsic material, and there are no polarization charges or net residual charges. The motion and position states of charge carriers in each discrete slice are known. Furthermore, the charge carriers satisfy the non-degenerate approximation (consistent with low illumination conditions). The number of charge carriers in each discrete slice is constant, assuming that charge carriers do not recombine or generate, and a linear approximation is applied.

[0083] Given the above prerequisites, the following operations can be performed:

[0084] The intrinsic absorption region thickness D is set to 600 cm, the initial velocity (Speed) of the photogenerated carriers is 1 m / s, the total simulation time is 100 s, ΔT is 0.01 s, the number of discrete slices is 100 s / 0.01 s = 10000; %number = 100; initialize the starting position (Position) and ending position (Position_end) of the photogenerated carriers.

[0085] Parameter settings for discrete slicing: Slice point selection, point_0 equals 0; slice height or slice carrier linear density (High) = 40 + 40 × point_0; slice width d i (whith) = 100.

[0086] Calculate the discrete slices: the acceleration of photogenerated carriers a_accelerate = 15; for any i-th discrete slice, loop as follows with i between 1 and number, with a step size of 1: set the time observation position T_T = ΔT × i; set Position(i) = Speed ​​× T_T + 0.5 × a_accelerate × T_T × T_T; set Position_end(i) = Position(i) + whith; determine if Position_end(i) is greater than D. If Position_end(i) is not greater than D, loop the above operations of setting Position(i) and setting Position_end(i) until Position_end(i) = D, then end the loop, indicating that the slice has been discretized and the slice family is obtained.

[0087] Calculation of the target field distribution information of photogenerated carriers at the target location:

[0088] Set X = linspace(0, D, 200) to take points in the intrinsic absorption region of the material; initialize the number of charge carriers E_TOTAL = []; initialize the target position diff_0 = []; initialize the number of discrete slices count = [].

[0089] For i = 1:1:length(X), perform the following loop:

[0090] Calculate the target position: E_TOTAL(i) = 0; count(i) = 0

[0091] For the loop `for j = 1:1:number`, the following loop is executed:

[0092] In the cases of (X(i)>Position(j)||X(i)==Position(j)) and X(i)<Position_end(j):

[0093] Set diff_0(i, j) = X(i) - Position(j);

[0094] High = 800 / 3 + 150 - 1 * diff_0(i, j); % Slice height description

[0095] E_TOTAL(i)=E_TOTAL(i)+High;

[0096] count(i) = count(i) + 1, and the above loop ends when i reaches length(X).

[0097] Finally, the target field distribution information of photogenerated carriers at the target location is output. This information can be combined with... The results were the same.

[0098] It is understandable that the above process can be implemented using programming software with relevant technologies to write relevant script code. The result obtained using the above operations can be shown below.

[0099] Figure 3 A schematic diagram of a timing transient superposition algorithm according to an embodiment of the present disclosure is shown.

[0100] like Figure 3 As shown, the first observation period represents the state of the charge carriers when they are not moving. The second observation period represents the state of the charge carriers after a movement time of ΔT. The third observation period represents the state of the charge carriers after a movement time of 2ΔT. The fourth observation period represents the state of the charge carriers after a movement time of 3ΔT. And so on, the nth observation period represents the state of the charge carriers after a movement time of n-1ΔT.

[0101] Figure 4A A schematic diagram illustrating the superposition process according to an embodiment of the present disclosure is shown. Figure 4B The illustration shows a schematic diagram of the overlay using a script according to an embodiment of the present disclosure.

[0102] like Figure 4A As shown, the superposition of N slices represents the field distribution of charge carriers under continuous illumination. Figure 4B This is a diagram created by iterating and overlaying using a script. It shows that under ideal conditions... Figure 4A and Figure 4B The curves shown have the same trend, and the superposition results are consistent.

[0103] Figure 5A A schematic diagram illustrating the target field distribution information of photogenerated carriers according to an embodiment of the present disclosure is shown. Figure 5B A schematic diagram illustrating the target field distribution information of photogenerated carriers according to another embodiment of the present disclosure is shown.

[0104] Furthermore, in the shape of discrete slices such as Figure 2 In the case shown, and when the carriers are accelerated, the target field distribution information of the photogenerated carriers can be as follows: Figure 5A As shown, the target field distribution of photogenerated carriers gradually stabilizes with increasing duration.

[0105] Furthermore, in the shape of discrete slices such as Figure 2In the case shown, and when carriers are accelerated, if the length of the discrete slice is shorter than the transit length of the carriers (simulating a situation where the material partially absorbs and partially does not absorb), the target field distribution information of the photogenerated carriers can be as follows: Figure 5B As shown, a spike-shaped charge layer exists at the boundary between absorption and non-absorption, which increases the difficulty of carrier extraction. Furthermore, the target field distribution of photogenerated carriers gradually stabilizes with increasing time.

[0106] This disclosure provides an isochronous transient superposition method for the field distribution of photogenerated carriers, enabling the prediction and analysis of the saturation mechanism of light-matter interaction. This algorithm transforms a time-varying calculus problem into an isochronous functional problem to explain the high saturation phenomenon of photogenerated carriers. This method is relatively simple; compared to solving a system of differential equations, it does not incur significant computational time. Therefore, it can efficiently and easily determine the field distribution information of photogenerated carriers under conditions of non-uniform material composition distribution or gradual changes in the material growth interface. This allows for more accurate feedback and adjustment of the simulation of device materials, thereby improving the simulation efficiency and accuracy of the simulation results.

[0107] It should be noted that, unless it is explicitly stated that there is a sequential order of execution between different operations, or that there is a sequential order of execution between different operations in terms of technical implementation, the execution order between multiple operations may not be significant, and multiple operations may be executed simultaneously.

[0108] Based on the aforementioned isochronous transient superposition method for photogenerated carrier field distribution, this disclosure also provides an isochronous transient superposition device for photogenerated carrier field distribution. The following will be combined with... Figure 6 The device is described in detail.

[0109] Figure 6 A schematic block diagram of an isochronous transient superposition device for photogenerated carrier field distribution according to an embodiment of the present disclosure is shown.

[0110] like Figure 6 As shown, the isochronous transient superposition device 600 for the photogenerated carrier field distribution in this embodiment includes a discrete module 610, a first iteration module 620, and a first superposition module 630.

[0111] Discretization module 610 is used to discretize the motion time of photogenerated carriers in the intrinsic absorption region of the material to obtain a family of discrete slices.

[0112] The first iteration module 620 is used to iteratively determine the photogenerated carrier distribution information of each discrete slice in the discrete slice family until the photogenerated carriers of all discrete slices in the discrete slice family are completely swept out by the electric field.

[0113] The first superposition module 630 is used to superimpose the photogenerated carrier distribution information at any first target location in the intrinsic absorption region of the material to obtain the target field distribution information of the photogenerated carriers.

[0114] According to the isochronous transient superposition method and apparatus for photogenerated carrier field distribution provided in this disclosure, the motion time of photogenerated carriers in the intrinsic absorption region of the material is discretized to obtain a family of discrete slices; the photogenerated carrier distribution information of each discrete slice in the family of discrete slices is determined iteratively until the photogenerated carriers of all discrete slices in the family of discrete slices are completely swept out by the electric field; at any first target position in the intrinsic absorption region of the material, the photogenerated carrier distribution information at the first target position is superimposed to obtain the target field distribution information of photogenerated carriers. Since the motion time of photogenerated carriers is discretized and the photogenerated carrier distribution information of each discrete slice is determined in the process of determining the photogenerated carrier field distribution information, when the photogenerated carrier field distribution at any target position is required, the photogenerated carrier information distribution information of the discrete slice at the target position can be superimposed to eliminate the time process of extracting carriers when the material composition distribution is uneven, and the method can obtain the field distribution information of photogenerated carriers without solving a system of differential equations, thus avoiding the time consumption of solving a system of differential equations. This method is relatively simple and at least partially overcomes the problem of difficulty in efficiently and easily determining the distribution of photogenerated carriers in materials in related technologies. It can efficiently and easily determine the field distribution information of photogenerated carriers under the phenomena of uneven material composition distribution or gradual changes in the material growth interface. This can provide more accurate feedback and debugging for the simulation of device materials, thereby improving the simulation efficiency and accuracy of material simulation results.

[0115] According to embodiments of this disclosure, the first iteration module may include a first determining unit and a second determining unit.

[0116] The first determining unit is used to determine the generation rate information and recombination rate information of photogenerated carriers in absolute coordinates.

[0117] The second determining unit is used to calculate the distribution information of photogenerated carriers in the absolute coordinates based on the generation rate information in the absolute coordinates, the recombination rate information of photogenerated carriers, and the discrete time period of the discrete slice.

[0118] According to embodiments of this disclosure, the isochronous transient superposition device for photogenerated carrier field distribution may further include an acquisition unit, a coordinate transformation unit, a construction unit, and a calculation unit.

[0119] The acquisition unit is used to obtain the absolute starting position coordinates of the discrete slice in absolute coordinates.

[0120] The coordinate transformation unit is used to perform coordinate transformation on the absolute starting position coordinates based on the relative coordinate vector in the relative coordinates and absolute coordinates, so as to obtain the relative starting position coordinates of the discrete slice in the relative coordinates.

[0121] The building unit is used to construct the generation rate information and recombination rate information of photogenerated carriers in relative coordinates based on the relative starting position coordinates.

[0122] The calculation unit is used to calculate the distribution information of photogenerated carriers in the relative coordinates based on the generation rate information in the relative coordinates, the recombination rate information of photogenerated carriers, and the discrete time period of the discrete slice.

[0123] According to embodiments of this disclosure, the first overlay module may include a calling unit, a third determining unit, and an input unit.

[0124] The calling unit is used to call the superposition function of photogenerated carriers.

[0125] The third determining unit is used to determine the discrete slice at the location of the first target.

[0126] The input unit is used to input the distribution information of photogenerated carriers of discrete slices into the superposition function and output the target field distribution information of photogenerated carriers.

[0127] According to embodiments of this disclosure, the isochronous transient superposition device for photogenerated carrier field distribution may further include an illumination module, a first determining module, and a construction module.

[0128] The irradiation module is used to irradiate any discrete slice in the discrete slice family with pulsed light, so as to change the photogenerated carrier line density information and the shape of the discrete slice through the pulsed light. The discrete slice irradiated by the pulsed light is called the irradiated slice.

[0129] The first determining module is used to determine the photogenerated carrier distribution information of the irradiated slice based on the changed photogenerated carrier linear density information and the shape of the discrete slice.

[0130] The module is used to construct a photogenerated carrier field distribution model under pulsed light irradiation based on the photogenerated carrier distribution information of the irradiated slice.

[0131] According to embodiments of this disclosure, the isochronous transient superposition device for photogenerated carrier field distribution may further include a second determining module and a second superposition module.

[0132] The second determining module is used to determine the set of target locations in the intrinsic absorption region of the material where continuous light irradiation occurs.

[0133] The second overlay module is used to overlay the photogenerated carrier distribution information at each of the second target locations in the target location set, thereby obtaining a photogenerated carrier field distribution model under continuous illumination.

[0134] According to embodiments of this disclosure, the isochronous transient superposition device for photogenerated carrier field distribution may further include a damping application module, a second iteration module, and a third superposition module.

[0135] A damping application module is used to obtain a family of damped discrete slices when damping is applied to the velocity of photogenerated charge carriers.

[0136] The second iteration module is used to iteratively determine the photogenerated carrier distribution information of each damped discrete slice in the damped discrete slice family, until the photogenerated carriers of all damped discrete slices in the damped discrete slice family are completely swept out by the electric field.

[0137] The third overlay module is used to overlay the photogenerated carrier analysis information of the damped discrete slice at any third target location in the intrinsic absorption region, and to construct a photogenerated carrier field distribution model under damping conditions.

[0138] According to embodiments of this disclosure, the isochronous transient superposition device for photogenerated carrier field distribution may further include a removal module.

[0139] The removal module is used to sequentially remove the photogenerated carrier distribution information of discrete slices from the target field distribution information of photogenerated carriers in order to construct a photogenerated carrier field distribution model under illumination-off conditions.

[0140] According to embodiments of this disclosure, any plurality of modules among discrete module 610, first iteration module 620, and first superposition module 630 can be merged into one module, or any one of these modules can be split into multiple modules. Alternatively, at least a portion of the functionality of one or more of these modules can be combined with at least a portion of the functionality of other modules and implemented in one module. According to embodiments of this disclosure, at least one of discrete module 610, first iteration module 620, and first superposition module 630 can be at least partially implemented as hardware circuitry, such as field-programmable gate array (FPGA), programmable logic array (PLA), system-on-a-chip, system-on-a-substrate, system-on-package, application-specific integrated circuit (ASIC), or implemented by any other reasonable means of integrating or packaging circuitry, or implemented in any one of software, hardware, and firmware, or in a suitable combination of any of these. Alternatively, at least one of discrete module 610, first iteration module 620, and first superposition module 630 can be at least partially implemented as a computer program module, which, when run, can perform corresponding functions.

[0141] It should be noted that the isochronous transient superposition device part of the photogenerated carrier field distribution in the embodiments of this disclosure corresponds to the isochronous transient superposition method part of the photogenerated carrier field distribution in the embodiments of this disclosure. For a detailed description of the isochronous transient superposition device part of the photogenerated carrier field distribution, please refer to the isochronous transient superposition method part of the photogenerated carrier field distribution, which will not be repeated here.

[0142] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatuses and methods according to various embodiments of the present disclosure. In this regard, each block in a flowchart or block diagram may represent a portion of a module containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0143] Those skilled in the art will understand that the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0144] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A method for isochronous transient superposition of photogenerated carrier field distributions, comprising: The motion time of photogenerated carriers in the intrinsic absorption region of the material is discretized to obtain a family of discrete slices; The distribution information of photogenerated carriers in each discrete slice in the discrete slice family is determined iteratively until the photogenerated carriers in all discrete slices in the discrete slice family are completely swept out by the electric field. At any first target location in the intrinsic absorption region of the material, the distribution information of the photogenerated carriers at the first target location is superimposed to obtain the target field distribution information of the photogenerated carriers.

2. The method according to claim 1, wherein, The discrete slice has discrete time periods; The step of iteratively determining the photogenerated carrier distribution information for each discrete slice in the discrete slice family includes: Determine the generation rate information and recombination rate information of the photogenerated carriers in absolute coordinates; Based on the generation rate information in the absolute coordinates, the recombination rate information of the photogenerated carriers, and the discrete time period of the discrete slice, the photogenerated carrier distribution information of the discrete slice in the absolute coordinates is calculated.

3. The method according to claim 2, further comprising: Obtain the absolute starting position coordinates of the discrete slice in the absolute coordinate system; Based on the relative coordinates and the relative coordinate vector in the absolute coordinates, the absolute starting position coordinates are transformed to obtain the relative starting position coordinates of the discrete slice in the relative coordinates; Based on the relative starting position coordinates, construct the generation rate information and recombination rate information of the photogenerated carriers in the relative coordinates; Based on the generation rate information in the relative coordinates, the recombination rate information of the photogenerated carriers, and the discrete time period of the discrete slice, the photogenerated carrier distribution information of the discrete slice in the relative coordinates is calculated.

4. The method according to claim 1, wherein, The superposition of the photogenerated carrier distribution information at the first target location includes: Call the superposition function of photogenerated carriers; Determine the discrete slice at the first target location; The photogenerated carrier distribution information of the discrete slice is input into the superposition function, and the target field distribution information of the photogenerated carrier is output.

5. The method according to claim 1, wherein, The discrete slice includes photogenerated carrier line density information; The method further includes: Any discrete slice in the discrete slice family is irradiated with pulsed light to change the photogenerated carrier line density information and the shape of the discrete slice, wherein the discrete slice irradiated by the pulsed light is called the irradiated slice; Based on the altered photogenerated carrier linear density information and the shape of the discrete slice, the photogenerated carrier distribution information of the irradiated slice is determined; Based on the photogenerated carrier distribution information of the irradiated slice, a photogenerated carrier field distribution model under pulsed light irradiation is constructed.

6. The method according to claim 1, further comprising: Determine the set of target locations where continuous light irradiation occurs within the intrinsic absorption region of the material; For all second target locations in the target location set, the photogenerated carrier distribution information at each second target location is superimposed to obtain the photogenerated carrier field distribution model under continuous illumination.

7. The method according to claim 1, further comprising: By applying damping to the velocity of the photogenerated carriers, a family of damped discrete slices is obtained; The photogenerated carrier distribution information of each damped discrete slice in the damped discrete slice family is determined iteratively until the photogenerated carriers of all damped discrete slices in the damped discrete slice family are completely swept out by the electric field. At any third target location in the intrinsic absorption region, the photogenerated carrier analysis information of the damped discrete slice at the third target location is superimposed to construct a photogenerated carrier field distribution model under damping conditions.

8. The method according to claim 1, further comprising: In the target field distribution information of the photogenerated carriers, the photogenerated carrier distribution information of the discrete slices is removed in sequence to construct a photogenerated carrier field distribution model under the condition of illumination off.

9. The method according to claim 1, wherein, The shape of the discrete slice is related to the type of material, and the shape of the discrete slice includes at least one of the following: a smooth curve shape for materials with graded composition, a step shape for stepped materials, and a serrated shape for quantum well materials.

10. A time-transient superposition device for photogenerated carrier field distribution, comprising: The discrete module is used to discretize the motion time of photogenerated carriers in the intrinsic absorption region of the material, resulting in a family of discrete slices; The first iteration module is used to iteratively determine the photogenerated carrier distribution information of each discrete slice in the discrete slice family until the photogenerated carriers of the last discrete slice in the discrete slice family are completely swept out by the electric field. The first superposition module is used to superimpose the photogenerated carrier distribution information at any first target location in the intrinsic absorption region to obtain the target field distribution information of the photogenerated carriers.

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