A device epitaxial layer parameter estimation method, system and power device structure

Abstract

The present application relates to a kind of device epitaxial layer parameter estimation method, system, power device structure in the field of semiconductor technology, comprising the following steps: calculating the total volume of device depletion region-depth function relationship formula;Based on total volume-depletion depth function relationship formula, obtain the capacitance-voltage function relationship formula of device, and based on capacitance-voltage function relationship formula, generate the apparent doping concentration-epitaxial depth function relationship formula of epitaxial layer;Through experimental test, obtain the capacitance-voltage characteristic data of device, and based on capacitance-voltage characteristic data, calculate the apparent doping concentration-epitaxial depth data of epitaxial layer;Using curve fitting method, fit apparent doping concentration-epitaxial depth function relationship formula and apparent doping concentration-epitaxial depth data, obtain the actual doping concentration and epitaxial thickness of device epitaxial layer, solve the problem of accurately calculating the doping concentration and thickness of device epitaxial layer without damaging device.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and specifically to a method, system, and power device structure for estimating epitaxial layer parameters. Background Technology

[0002] Power semiconductor devices are core components in power electronics technology. The doping concentration and thickness of their epitaxial layers are among the most important parameters, as they largely determine the device's on-resistance and breakdown voltage. Various methods exist for extracting the doping concentration distribution along depth in semiconductor materials, with secondary ion mass spectroscopy (SIMS) and capacitance-voltage (CV) methods being the two most common.

[0003] Among them, the SIMS method, which involves peeling off the sample surface layer by layer with an ion beam and measuring the concentration of the target doped impurities in each layer, is the most direct measurement method. However, this method requires specialized equipment and specially prepared test samples, resulting in high cost and low efficiency. Furthermore, the method has limited accuracy, only measuring the total doping concentration and unable to distinguish the concentration of activated dopants. Additionally, this method is destructive and unsuitable for pre-fabricated devices.

[0004] The capacitance-voltage (CV) method measures the capacitance-voltage characteristics of a device using electrical methods and calculates the change in doping concentration with depth within the epitaxial layer based on the relationship between reverse bias, depletion region width, and junction capacitance. As a purely electrical and non-destructive testing method, it has a wide range of applications and is very suitable for analyzing fabricated devices; therefore, it is the most commonly used method for measuring epitaxial layer parameters.

[0005] However, power semiconductor devices experience high blocking voltages in the blocking state, resulting in high electric field strength within their epitaxial layers. This electric field is more concentrated at the edges of the active region, where the field strength is higher than inside the active region, potentially leading to premature breakdown. To mitigate this field concentration at the device edges, termination structures are typically present around the active region of power devices. These structures reduce the electric field strength at the edges by modulating the electric field distribution. However, the presence of these termination structures causes the depletion region to expand in a manner deviating from the typical parallel planar junction pattern under reverse bias, thus affecting the device's capacitance-voltage characteristics. This leads to deviations when using the CV method to calculate epitaxial layer parameters.

[0006] Specifically, junction extension is one of the commonly used termination structures for power devices. Junction extension is a lightly doped region of the same conductivity type that naturally extends from the main junction towards the device edge. When the device is subjected to a blocking voltage, the junction extension region is completely depleted, and the fixed charge within it redistributes the electric field based on Gauss's law, thereby easing the electric field and reducing its intensity. Like other types of termination, junction extension also alters the device's capacitance-voltage characteristics, leading to deviations in the epitaxial parameters calculated using the CV method. Summary of the Invention

[0007] This invention addresses the shortcomings of existing technologies by providing a method, system, and power device structure for estimating epitaxial layer parameters, solving the problem of accurately calculating the doping concentration and thickness of the epitaxial layer without damaging the device.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0009] A method for estimating parameters of an epitaxial layer of a device includes the following steps:

[0010] The total volume of the device's depletion region versus the depletion depth function is calculated.

[0011] The capacitance-voltage function of the device is obtained based on the total volume-depletion depth function, and the apparent doping concentration-epitaxy depth function of the epitaxial layer is generated based on the capacitance-voltage function.

[0012] Through experimental testing, the capacitance-voltage characteristic data of the device were obtained, and the apparent doping concentration-epitaxy depth data of the epitaxial layer were calculated based on the capacitance-voltage characteristic data.

[0013] By using a curve fitting method, the apparent doping concentration-epipolar depth function relationship is fitted to the apparent doping concentration-epipolar depth data to obtain the actual doping concentration and epitaxial thickness of the device epitaxial layer.

[0014] Optionally, the total volume of the device's depletion region versus the depletion depth function is calculated, including the following steps:

[0015] In the device blocking state, the depletion region of the epitaxial layer of the device is treated as an approximate geometry;

[0016] By repeatedly changing the applied voltage, the dimensional change parameters of the device depletion region under different applied voltages are obtained;

[0017] Based on the aforementioned size variation parameters, a function relating the total volume to the depletion depth of the device's depletion region is generated.

[0018] Optionally, obtaining the capacitance-voltage function of the device based on the total volume-depletion depth function includes the following steps:

[0019] By obtaining the relationship between voltage and depletion depth under different applied voltages, the voltage-depletion depth function is obtained;

[0020] Based on the definition of capacitance, the voltage-depletion depth function relationship, and the total volume-depletion depth function relationship, a capacitance-voltage function relationship is generated.

[0021] Optionally, the total volume-depletion depth function relationship is:

[0022]

[0023] Among them, M tot (y epi ) represents the total volume, A represents the active area of ​​the device, and y represents the total volume. epi L represents the depth of the depletion region below the P+ region of the device. JTE x is the length of the junction termination extension structure of the device. JTE x represents the width of the depletion region within the junction termination extension structure of the device. epi To extend the width of the depletion region inside the epitaxial layer of the device, y P+ The depth of the P+ region;

[0024] The capacitance-voltage function relationship is as follows:

[0025]

[0026] Where C is capacitance, q is charge, and N is... epi V represents the actual doping concentration of the epitaxial layer of the device. R The potential at the cathode of the device. N JTE The doping concentration of the junction-terminated extended structure, ε s Let a be the dielectric constant of the semiconductor. 32 a 21 a 10 a 00 b 53 b 42 b 32 b 31 b 21 b 20 b 10 b 00 All are undetermined coefficients.

[0027] Optionally, generating the apparent doping concentration-epitaxy depth function relationship of the epitaxial layer based on the capacitance-voltage function relationship includes the following steps:

[0028] Based on the parallel planar junction model, the apparent doping concentration-capacitance relationship is derived.

[0029] Based on the apparent doping concentration-capacitance relationship and the capacitance-voltage function relationship, the apparent doping concentration-epitaxy depth function relationship is obtained.

[0030] Optionally, the apparent doping concentration-epipolar depth function relationship is:

[0031]

[0032] Optionally, the capacitance-voltage characteristic data of the device is acquired, and the apparent doping concentration-epitaxy depth data of the epitaxial layer is calculated based on the capacitance-voltage characteristic data, including the following steps:

[0033] The capacitance-voltage characteristic data of the measuring device is obtained by measuring the capacitance-voltage characteristic data.

[0034] Based on the capacitance-voltage characteristic data and the apparent doping concentration-capacitance relationship, the apparent doping concentration-epitaxy depth data of the epitaxial layer is obtained.

[0035] Optionally, fitting the apparent doping concentration-epitaxy depth function relationship with the apparent doping concentration-epitaxy depth data includes the following steps:

[0036] Define the curve distance and establish a functional relationship between the curve distance and the actual doping concentration and epitaxial thickness of the epitaxial layer.

[0037] Wherein, the curve distance is the distance between the curve corresponding to the apparent doping concentration-epipolar depth function and the curve corresponding to the apparent doping concentration-epipolar depth data.

[0038] Optionally, obtaining the actual doping concentration and epitaxial thickness of the device epitaxial layer includes the following steps:

[0039] The minimum value of the curve distance is obtained, and based on the minimum value, the actual doping concentration and epitaxial thickness of the epitaxial layer are obtained.

[0040] A device epitaxial layer parameter estimation system, wherein the device epitaxial layer parameter estimation system performs the device epitaxial layer parameter estimation method as described in any one of the above, including a function relationship generation unit one, a function relationship generation unit two, a function relationship generation unit three, and a fitting unit;

[0041] The function relationship generation unit is used to calculate the function relationship between the total volume and depletion depth of the device's depletion region.

[0042] The second function relationship generation unit is used to obtain the capacitance-voltage function relationship of the device based on the total volume-depletion depth function relationship, and to generate the apparent doping concentration-epitaxy depth function relationship of the epitaxial layer based on the capacitance-voltage function relationship.

[0043] The third function relationship generation unit is used to obtain the capacitance-voltage characteristic data of the device through experimental testing, and to calculate the apparent doping concentration-epitaxy depth data of the epitaxial layer based on the capacitance-voltage characteristic data.

[0044] The fitting unit is used to fit the apparent doping concentration-epipolar depth function relationship with the apparent doping concentration-epipolar depth data using a curve fitting method, so as to obtain the actual doping concentration and epitaxial thickness of the device epitaxial layer.

[0045] A computer-readable storage medium storing a computer program, which, when executed by a processor, performs the device epitaxial layer parameter estimation method described in any of the preceding claims.

[0046] A power device structure, wherein the power device structure uses the device epitaxial layer parameter estimation method as described in any one of the above to obtain the actual doping concentration and epitaxial thickness of the device epitaxial layer.

[0047] Compared with the prior art, the technical solution provided by this invention has the following advantages:

[0048] By obtaining capacitance-voltage characteristic data of the device through electrical testing and combining it with model calculations, high-precision estimation of the actual doping concentration and epitaxial thickness of the device epitaxial layer can be achieved, which greatly improves the estimation efficiency, is low in cost, and avoids the damage caused by the traditional SIM method of peeling off the sample surface layer by layer with ion beam and measuring the concentration of target doped impurities in each layer. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a flowchart of a device epitaxial layer parameter estimation method proposed in Embodiment 1;

[0051] Figure 2This is a cross-sectional view of the terminal region of a power device structure with a junction termination extension structure proposed in Embodiments 1 and 3.

[0052] Figure 3 This is a top view of a power device structure with a junction termination extension structure proposed in Embodiment 1.

[0053] Figure 4 This is a schematic diagram illustrating the principle of deriving the apparent doping concentration-epipolar depth function relationship proposed in Embodiment 1.

[0054] Reference numerals: 01, anode; 02, cathode; 03, passivation structure; 04, epitaxial layer; 05, substrate layer; 10, P+ region; 20, junction termination extension structure. Detailed Implementation

[0055] The present invention will be further described in detail below with reference to the embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0056] Example 1

[0057] like Figure 1 As shown, a method for estimating parameters of an epitaxial layer of a device includes the following steps: calculating the total volume-depletion depth function relationship of the device depletion region, specifically including the following steps: under the device blocking state, approximating the geometry of the depletion region of the device epitaxial layer 04; repeatedly changing the applied voltage to obtain the size change parameters of the device depletion region under different applied voltages; and generating the total volume-depletion depth function relationship of the device depletion region based on the size change parameters.

[0058] Specifically, the first step is to derive the relationship between critical dimensions as the device depletion region expands, such as... Figure 2 As shown, the AB connection represents the PN junction formed between the P+ region 10 and the epitaxial layer 04, and the BJK connection represents the PN junction formed between the junction termination extension structure 20 and the epitaxial layer 04. Assume the actual doping concentration of the epitaxial layer 04 is N. epi Thickness is t epi The depth of region P+10 is y. P+ The doping concentration is much higher than that of epitaxial layer 04 and junction termination extension structure 20; the doping concentration of junction termination extension structure 20 is N. JTE The length is L JTE Assuming the device is in a blocking state, the potentials applied to the anode 01 and cathode 02 are 0 and V, respectively. RThe ABCDEKFGHI connection region is the depletion region below the termination region. It extends on both sides of the BJK connection in the PN junction. Specifically, the depletion region in the junction termination extension structure 20 is the BCDEKJ region, and the depletion region in the epitaxial layer 04 is the BJKFGH region. The depth of the depletion region below the P+ region 10, i.e., the length of the AI ​​connection, is y. epi The depth of the depletion region inside the terminal extension structure 20, i.e., the length of the BC connection, is y. JTE The width of the depletion region inside the terminal extension structure 20, i.e., the length of the EK connection, is x. JTE The width of the depletion region inside epitaxial layer 04, i.e., the length of KF, is x. epi Below the junction terminal extension structure 20, a portion of the depletion region approximates the straight line HG, with a length of L. JTE -x JTE The other part approximates the elliptical arc GF.

[0059] Since the fixed charge contained in the depletion region on both sides of the BJK connection of the PN junction should satisfy the law of charge conservation, we have the following formula:

[0060] The area S of the BJKFGH region epi ×N epi = Area S of region BCDEKJ JTE ×N JTE Equation (1).

[0061] according to Figure 2 Based on the geometric relationships, the areas of regions BJKFGH and BCDEKJ can be obtained as follows:

[0062]

[0063] Substituting equation (2) into equation (1), we get:

[0064]

[0065] Assuming the depletion region expansion pattern on both sides of PN junction 21 approximates a parallel planar junction, then we have Substituting into equation (3), we get:

[0066]

[0067] Assume x epi With y epi The two are directly proportional, i.e., x epi =ky epi and set Then we have:

[0068]

[0069] The above expresses several key dimensions of the depletion region as the depletion region thickness y. epi The function completes the derivation of the relationship between critical dimensions when the device depletion region expands.

[0070] Furthermore, the total volume-depletion depth function relationship of the device's depletion region is derived, as follows: Figure 3 As shown, the active region ABCD of the device is a square with an area of ​​A. Horizontally, the depletion region extends outwards from the active region, forming four side regions BFGC, DCHI, KADJ, and LABE, and four corner regions BEF, CGH, JDI, and LAK. Below the active region, the depletion region extends only within the epitaxial layer 04, with a depth of y. epi The corresponding volume is:

[0071] M1(y epi ) = Ay epi Equation (6).

[0072] Four lateral depletion regions (BFGC, DCHI, KADJ, LABE) and four corner depletion regions (BEF, CGH, JDI, LAK) extend within epitaxial layer 04 and junction termination extension structure 20, respectively. The depletion regions beneath the four lateral depletion regions (BFGC, DCHI, KADJ, LABE) are columnar, with a cross-section of [missing information]. Figure 2 The BJKFGH region shown has a corresponding cross-sectional area of ​​S. epi (Equation (2)), therefore, the sum of the volumes of the four side depletion regions BFGC, DCHI, KADJ, and LABE is:

[0073]

[0074] The four corner depletion regions BEF, CGH, JDI, and LAK exhibit the shape of a solid of revolution, with their rotation axes being... Figure 2 The cross section of the BH line shown is... Figure 2 The volume of the BJKFGH region shown is:

[0075]

[0076] Among them, M1(y epi M2(y) epi M3(y) epi Adding them together gives the total volume of the device's depletion region as a function of depletion depth:

[0077]

[0078] Furthermore, the capacitance-voltage function of the device is obtained based on the total volume-depletion depth function relationship, specifically including the following steps: obtaining the relationship between voltage and depletion depth of the depletion region under different applied voltages to obtain the voltage-depletion depth function relationship; and generating the capacitance-voltage function relationship based on the capacitance definition, the voltage-depletion depth function relationship, and the total volume-depletion depth function relationship.

[0079] Specifically, assume that the expansion of the depletion region below the active region follows the parallel planar junction rule, that is, when the depletion region expands, the boundary of the depletion region is parallel to the main junction, and the whole expands downwards. Let be the case where the depletion region is denoted as . Then we have the voltage-depletion depth function relationship:

[0080]

[0081] Based on the definition of capacitance and the total volume-depletion depth function relationship (9), we have:

[0082] According to equation (5), we can obtain:

[0083] Substituting the above equation into equations (6), (7), and (8), we get:

[0084]

[0085] Among them are:

[0086]

[0087] Substituting equations (13) and (14) into equation (11), we obtain the capacitance-voltage function relationship:

[0088]

[0089] Where, ε s Let a be the dielectric constant of the semiconductor. 32 a 21 a 10 a 00 b 53 b 42 b 32 b 31 b 21 b 20 b 10 b 00 All are undetermined coefficients.

[0090] Furthermore, based on the capacitance-voltage function relationship, the apparent doping concentration-epitaxy depth function relationship of epitaxial layer 04 is generated, specifically including the following steps: based on the parallel planar junction model, the apparent doping concentration-capacitance relationship is derived; based on the apparent doping concentration-capacitance relationship and the capacitance-voltage function relationship, the apparent doping concentration-epitaxy depth function relationship is obtained.

[0091] Specifically, such as Figure 4 As shown, the device is considered as a parallel planar junction. Assume the active region area of ​​the device is A, and the reverse bias voltage is V. R The depth of the depletion region is y epi The total capacitance of the device is C. When the reverse bias voltage V R Add dV R At that time, the depth of the depletion region is y epi Add dy epi If the charge Q stored in the junction capacitance is increased by dQ, then:

[0092] dQ=C·dV R =qN(y epi A·dy epi Equation (16).

[0093] Therefore:

[0094] Due to consideration Therefore, the apparent doping concentration-capacitance relationship is obtained:

[0095]

[0096] Substituting equation (15) into the above equation, we obtain the functional relationship between apparent doping concentration and epitaxial depth:

[0097]

[0098] Furthermore, through experimental testing, the capacitance-voltage characteristic data of the device is obtained, and the apparent doping concentration-epitaxy depth data of epitaxial layer 04 is calculated based on the capacitance-voltage characteristic data. Specifically, the following steps are included: measuring the capacitance-voltage characteristic data of the device to obtain capacitance-voltage characteristic data; and obtaining the apparent doping concentration-epitaxy depth data of epitaxial layer 04 based on the capacitance-voltage characteristic data and the apparent doping concentration-capacitance relationship.

[0099] Specifically, an electrical test platform is selected or constructed, and the anode 01 and cathode 02 of the device are connected to the test platform respectively; the frequency of the AC small signal is selected, zero voltage is applied to the anode 01, and a high voltage V gradually increasing from zero is applied to the cathode 02. RThe device is placed in a blocking state; then the test begins. After the test is completed, the device capacitance C is read as a function of the voltage applied to the cathode O2. R Data set {V R,i C i}, where i = 1, 2, ..., m (m is the total number of data points), which is the capacitance-voltage characteristic data of the device under test.

[0100] Then, based on the capacitance-voltage characteristic data of the device under test, the apparent doping concentration-epitaxial depth data of the device are calculated, as follows:

[0101] Capacitance C and depletion region depth y epi There are:

[0102]

[0103] Substituting the above equation into equation (16), we get:

[0104]

[0105] The capacitance-voltage characteristic data of the device under test {V R,i C i Substituting into the above equation, we get:

[0106]

[0107] The result obtained by the above formula is {y epi,i N i}, where i = 1, 2, ..., m-1, which is the experimental data of epitaxial depth-apparent doping concentration of the device under test.

[0108] Furthermore, a curve fitting method is used to fit the apparent doping concentration-epicentric depth function relationship with the apparent doping concentration-epicentric depth data to obtain the actual doping concentration and epitaxial thickness of the epitaxial layer 04. Specifically, this includes the following steps: setting the curve distance and establishing a function relationship between the curve distance and the actual doping concentration and epitaxial thickness of the epitaxial layer 04, where the curve distance is the distance between the curve corresponding to the apparent doping concentration-epicentric depth function relationship and the curve corresponding to the apparent doping concentration-epicentric depth data; obtaining the minimum value of the curve distance, and based on the minimum value, obtaining the actual doping concentration and epitaxial thickness of the epitaxial layer 04.

[0109] Specifically, the experimental data of epitaxial depth versus apparent doping concentration of the device under test {y epi,i N i} itself constitutes a known function Ni = F(y epi，i A value passing through all data points {y} can be obtained through interpolation. epi,i N iThe known curve N = F(y) epi The apparent doping concentration-epitaxy depth function relationship can be viewed as an undetermined curve N = N(y). epi N epi ,k,α,L JTE The distance function between F and G can be defined as:

[0110]

[0111] The idea behind curve fitting is to select undetermined coefficients k, α, and LJTE to minimize the distance between the curve and Dist(F, G) in the above equation. Based on the method for finding the extrema of multivariate functions, a system of equations and inequalities can be established, resulting in:

[0112]

[0113] The solution that satisfies the above set of equations and inequalities is the actual doping concentration and epitaxial thickness of the device under test.

[0114] Example 2

[0115] A device epitaxial layer parameter estimation system, which executes the device epitaxial layer parameter estimation method as described in Embodiment 1, includes a function relationship generation unit 1, a function relationship generation unit 2, a function relationship generation unit 3, and a fitting unit;

[0116] The first function relationship generation unit is used to calculate the total volume-depletion depth function relationship of the device's depletion region.

[0117] The second function relationship generation unit is used to obtain the capacitance-voltage function relationship of the device based on the total volume-depletion depth function relationship, and to generate the apparent doping concentration-epitaxy depth function relationship of the epitaxial layer based on the capacitance-voltage function relationship.

[0118] The third function relationship generation unit is used to obtain the capacitance-voltage characteristic data of the device through experimental testing, and to calculate the apparent doping concentration-epitaxy depth data of the epitaxial layer based on the capacitance-voltage characteristic data;

[0119] The fitting unit is used to fit the apparent doping concentration-epipolar depth function relationship and the apparent doping concentration-epipolar depth data using a curve fitting method, so as to obtain the actual doping concentration and epitaxial thickness of the device epitaxial layer.

[0120] A computer-readable storage medium storing a computer program, which, when executed by a processor, performs the device epitaxial layer parameter estimation method described in Embodiment 1.

[0121] More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wire segments, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0122] In this application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in connection with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wireless segments, wire segments, optical cables, RF, etc., or any suitable combination thereof.

[0123] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of modules, units, or units is merely a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units, modules, or components may be combined or integrated into another device, or some features may be ignored or not executed.

[0124] The units may or may not be physically separate. The components shown as units can be one or more physical units, meaning they can be located in one place or distributed in multiple different locations. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0125] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0126] In particular, according to embodiments disclosed in this invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of this disclosure include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication component, and / or installed from a removable medium. When the computer program is executed by a central processing unit (CPU), it performs the functions defined in the methods of this application. It should be noted that the computer-readable medium described above in this application can be a computer-readable signal medium or a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof.

[0127] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code 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 the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can 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.

[0128] Example 3

[0129] A power device structure is provided, wherein the device epitaxial layer parameter estimation method described in Example 1 is used to obtain the actual doping concentration and epitaxial thickness of the device epitaxial layer.

[0130] Specifically, the power device structure includes a substrate layer 05, an epitaxial layer 04, a passivation structure 03, a P+ region 10, a junction termination extension structure 20, an anode layer 01, and a cathode layer 02. The epitaxial layer 04 is disposed on the substrate layer 05. The passivation structure 03 is disposed on the other end face of the epitaxial layer 04. The anode layer 01 is also disposed on the other end face of the epitaxial layer 04. The anode layer 01 is in contact with the passivation structure 03. The cathode layer 02 is disposed on the end face of the substrate layer 05 away from the epitaxial layer 04. The P+ region 10 is disposed within the epitaxial layer 04 and is in contact with the anode layer 01. The junction termination extension structure 20 is also disposed within the epitaxial layer 04 and is in contact with both the junction termination extension structure 20 and the P+ region 10.

[0131] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions within the technical scope disclosed in the present invention should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for estimating parameters of an epitaxial layer of a device, characterized in that, Includes the following steps: The calculation of the total volume-depletion depth function relationship of the device depletion region specifically includes the following steps: In the device blocking state, the depletion region of the epitaxial layer is approximated as a geometric shape; the applied voltage is repeatedly changed to obtain the size change parameters of the device depletion region under different applied voltages; based on the size change parameters, the total volume-depletion depth function relationship of the device depletion region is generated, wherein the total volume-depletion depth function relationship is: ,in, Let A be the total volume and A be the area of ​​the active region of the device. This represents the depth of the depletion region below the P+ region of the device. The length of the junction termination extension structure of the device, The width of the depletion region inside the junction termination extension structure of the device. To extend the width of the depletion region inside the epitaxial layer of the device, The depth of the P+ region; The capacitance-voltage function of the device is obtained based on the total volume-depletion depth function, and the apparent doping concentration-epitaxy depth function of the epitaxial layer is generated based on the capacitance-voltage function. Specifically, obtaining the capacitance-voltage function relationship of the device based on the total volume-depletion depth function relationship includes the following steps: obtaining the relationship between voltage and depletion depth of the depletion region under different applied voltages, thus obtaining the voltage-depletion depth function relationship; and generating the capacitance-voltage function relationship based on the definition of capacitance, the voltage-depletion depth function relationship, and the total volume-depletion depth function relationship, wherein the capacitance-voltage function relationship is: Where C is capacitance and q is elementary charge. This represents the actual doping concentration of the device's epitaxial layer. The potential at the cathode of the device. , The doping concentration of the junction-terminated extended structure, , The dielectric constant of a semiconductor is _____. , , , , , , , , , , , All are undetermined coefficients; Specifically, generating the apparent doping concentration-epicentric depth function relationship of the epitaxial layer based on the capacitance-voltage function relationship includes the following steps: deriving the apparent doping concentration-capacitance relationship based on the parallel planar junction model; obtaining the apparent doping concentration-epicentric depth function relationship based on the apparent doping concentration-capacitance relationship and the capacitance-voltage function relationship, wherein the apparent doping concentration-epicentric depth function relationship is: ; Through experimental testing, the capacitance-voltage characteristic data of the device were obtained, and the apparent doping concentration-epitaxy depth data of the epitaxial layer were calculated based on the capacitance-voltage characteristic data. By using a curve fitting method, the apparent doping concentration-epipolar depth function relationship is fitted to the apparent doping concentration-epipolar depth data to obtain the actual doping concentration and epitaxial thickness of the device epitaxial layer.

2. The method for estimating epitaxial layer parameters of a device according to claim 1, characterized in that, Acquiring the capacitance-voltage characteristic data of the device and calculating the apparent doping concentration-epitaxy depth data of the epitaxial layer based on the capacitance-voltage characteristic data includes the following steps: The capacitance-voltage characteristic data of the measuring device is obtained by measuring the capacitance-voltage characteristic data. Based on the capacitance-voltage characteristic data and the apparent doping concentration-capacitance relationship, the apparent doping concentration-epitaxy depth data of the epitaxial layer is obtained.

3. The method for estimating epitaxial layer parameters of a device according to claim 1, characterized in that, Fitting the apparent doping concentration-epitaxy depth function relationship with the apparent doping concentration-epitaxy depth data includes the following steps: Define the curve distance and establish a functional relationship between the curve distance and the actual doping concentration and epitaxial thickness of the epitaxial layer. Wherein, the curve distance is the distance between the curve corresponding to the apparent doping concentration-epipolar depth function and the curve corresponding to the apparent doping concentration-epipolar depth data.

4. The method for estimating epitaxial layer parameters of a device according to claim 3, characterized in that, To obtain the actual doping concentration and epitaxial thickness of the device epitaxial layer, the following steps are included: The minimum value of the curve distance is obtained, and based on the minimum value, the actual doping concentration and epitaxial thickness of the epitaxial layer are obtained.

5. A device epitaxial layer parameter estimation system, characterized in that, The device epitaxial layer parameter estimation system executes the device epitaxial layer parameter estimation method as described in any one of claims 1-4, including a function relationship generation unit one, a function relationship generation unit two, a function relationship generation unit three, and a fitting unit; The function relationship generation unit is used to calculate the function relationship between the total volume and depletion depth of the device's depletion region. The second function relationship generation unit is used to obtain the capacitance-voltage function relationship of the device based on the total volume-depletion depth function relationship, and to generate the apparent doping concentration-epitaxy depth function relationship of the epitaxial layer based on the capacitance-voltage function relationship. The third function relationship generation unit is used to obtain the capacitance-voltage characteristic data of the device through experimental testing, and to calculate the apparent doping concentration-epitaxy depth data of the epitaxial layer based on the capacitance-voltage characteristic data. The fitting unit is used to fit the apparent doping concentration-epipolar depth function relationship with the apparent doping concentration-epipolar depth data using a curve fitting method, so as to obtain the actual doping concentration and epitaxial thickness of the device epitaxial layer.

6. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it performs the device epitaxial layer parameter estimation method according to any one of claims 1-4.

7. A power device structure, characterized in that, The power device structure uses the device epitaxial layer parameter estimation method as described in any one of claims 1-4 to obtain the actual doping concentration and epitaxial thickness of the device epitaxial layer.

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