Ultra-low temperature infrared photodiode modeling method, system and equipment

Abstract

The invention relates to the technical field of device modeling, and discloses an ultralow-temperature infrared photodiode modeling method, system and equipment. The method comprises the following steps: establishing a first target model of the ultralow-temperature infrared photodiode containing temperature parameters according to actual test data and an equivalent circuit of the ultralow-temperature infrared photodiode; matching the first simulation result of the first target model with actual test data; if the matching is successful, performing readout circuit simulation verification based on the first target model to obtain a second simulation result; and adjusting parameters of the first target model according to a matching result of the second simulation result and a preset design condition to obtain a second target model. According to the method, temperature parameters are added into parameters of an equivalent circuit, establishment of an ultralow-temperature infrared photodiode model under complete current bias is achieved, and the temperature limitation of a common model is broken through. Model parameters are adjusted and optimized based on a simulation result, and the requirement of an accurate ultralow-temperature device model in an ultralow-temperature working environment is met.

Description

Technical Field

[0001] The present invention relates to the field of device modeling technology, and in particular to a method, system and equipment for modeling an ultra-low temperature infrared photodiode. Background Art

[0002] Large-scale, highly integrated infrared focal plane devices are the core of infrared imaging and the frontier of infrared detection technology. Infrared detection photodiodes are one of the key components of focal plane arrays. Like common photodiodes, infrared detection photodiodes are also composed of P-type and N-type semiconductors. Because the radiation wavelength of infrared detectors is longer than that of visible light, the semiconductor materials used are mostly compound semiconductor materials with very small band gaps. Integrated circuits have the advantages of fast speed, low power consumption and high reliability in low temperature environments. In recent years, the low-temperature application of integrated circuits has received more and more attention and research. The SPICE model is a bridge connecting device technology and circuit design. Accurate SPICE simulation models are crucial for the design of high-performance integrated circuits.

[0003] The type, working mode and static working point of infrared detection photodiodes are related to the readout circuit, and the accuracy of their equivalent models is directly related to the correctness of the simulation results. Infrared detection photodiodes work in ultra-low temperature environments (for example, below -100°C). The working characteristics of devices in ultra-low temperature environments are different from those at normal temperatures due to the harsh temperature environment. At the same time, the low-temperature model of commonly used device models only supports simulation to -40°C. Due to the large temperature difference and the differences in device characteristics under ultra-low temperatures, the SPICE model in the process design toolkit cannot simulate ultra-low temperature circuits. Therefore, ultra-low temperature circuit design has an urgent need for the working characteristics of devices at ultra-low temperatures and accurate low-temperature device models. Summary of the invention

[0004] The main purpose of the present invention is to provide an ultra-low temperature infrared photodiode modeling method, system and equipment, aiming to solve at least one of the above-mentioned technical problems.

[0005] To achieve the above object, the present invention provides a method for modeling an ultra-low temperature infrared photodiode, comprising:

[0006] A first target model of an ultra-low temperature infrared photodiode including temperature parameters is established according to actual test data and an equivalent circuit of the ultra-low temperature infrared photodiode;

[0007] Matching a first simulation result of the first target model with the actual test data;

[0008] If the match is successful, performing a readout circuit simulation verification based on the first target model to obtain a second simulation result;

[0009] According to the matching result between the second simulation result and the preset design condition, the parameters of the first target model are adjusted to obtain the second target model.

[0010] In some embodiments, the step of establishing a first target model of an ultra-low temperature infrared photodiode including temperature parameters according to actual test data and an equivalent circuit of the ultra-low temperature infrared photodiode includes:

[0011] Obtain actual test data of ultra-low temperature infrared photodiodes;

[0012] Generate an HSPICE netlist including temperature parameters according to an equivalent circuit of an ultra-low temperature infrared photodiode and the actual test data;

[0013] Building an initial simulation model of an ultra-low temperature infrared photodiode based on the HSPICE netlist containing temperature parameters;

[0014] The parameters of the initial simulation model are adjusted according to the simulation results of the initial simulation model to obtain a first target model of the ultra-low temperature infrared photodiode.

[0015] In some embodiments, the equivalent circuit of the ultra-low temperature infrared photodiode includes: a photodiode internal series resistance, a differential equivalent resistance, and a photodiode junction capacitance; wherein,

[0016] The first end of the differential equivalent resistor is connected to the first end of the photodiode junction capacitor, the second end of the differential equivalent resistor is connected to the second end of the photodiode junction capacitor, and the second end of the differential equivalent resistor is also connected to the internal series resistor of the photodiode.

[0017] In some embodiments, generating an HSPICE netlist including temperature parameters according to the equivalent circuit of the ultra-low temperature infrared photodiode and the actual test data includes:

[0018] Determine the internal series resistance of the photodiode and the netlist parameters that affect the photodiode current based on the equivalent circuit of the ultra-low temperature infrared photodiode;

[0019] The temperature parameter is added to the resistance formula of the internal series resistance of the photodiode and the netlist parameters to obtain the HSPICE netlist of the ultra-low temperature infrared photodiode to achieve ultra-low temperature modeling under full current bias.

[0020] In some embodiments, matching the first simulation result of the first target model with the actual test data includes:

[0021] Performing simulation verification on the first target model to obtain a first simulation result;

[0022] The first simulation result is compared with the actual test data through data fitting to confirm whether the first simulation result matches the actual test data.

[0023] In some embodiments, performing readout circuit simulation verification based on the first target model to obtain a second simulation result includes:

[0024] Establishing a first version model of an ultra-low temperature infrared photodiode based on the first target model;

[0025] Create simulation schematics based on Cadence simulation software;

[0026] A readout circuit simulation verification is performed according to the simulation schematic diagram and the first version model to obtain a second simulation result.

[0027] In some embodiments, the simulation schematic diagram includes: a plurality of transistor units and an ultra-low temperature infrared photodiode; wherein,

[0028] The transistor unit includes a first transistor and a second transistor;

[0029] The cathode of the ultra-low temperature infrared photodiode is connected to the source of the first transistor, and the drain of the first transistor is connected to the drain of the second transistor.

[0030] In some embodiments, performing readout circuit simulation verification according to the simulation schematic and the first version model to obtain a second simulation result includes:

[0031] Substituting the ultra-low temperature infrared photodiode established by the first version model into the simulation schematic diagram for simulation verification;

[0032] By simulating the coupling characteristics of the ultra-low temperature infrared photodiode and the transistor of the simulation schematic diagram, circuit coupling characteristic data is obtained;

[0033] The circuit coupling characteristic data is used as a second simulation result.

[0034] In addition, to achieve the above purpose, the present invention also proposes an ultra-low temperature infrared photodiode modeling system, comprising:

[0035] A model building module, used to build a first target model of the ultra-low temperature infrared photodiode including temperature parameters according to actual test data and an equivalent circuit of the ultra-low temperature infrared photodiode;

[0036] A first matching module, used for matching a first simulation result of the first target model with the actual test data;

[0037] A coupling simulation module, configured to perform a readout circuit simulation verification based on the first target model to obtain a second simulation result if the matching is successful;

[0038] The second matching module is used to adjust the parameters of the first target model according to the matching result between the second simulation result and the preset design condition to obtain the second target model.

[0039] In addition, to achieve the above-mentioned purpose, the present invention also proposes an electronic device, which includes: a memory, a processor, and an ultra-low temperature infrared photodiode modeling program stored in the memory and runnable on the processor, and the ultra-low temperature infrared photodiode modeling program is configured to implement the ultra-low temperature infrared photodiode modeling method as described above.

[0040] The present invention provides a method for modeling an ultra-low temperature infrared photodiode, comprising: establishing a first target model of an ultra-low temperature infrared photodiode including temperature parameters according to actual test data and an equivalent circuit of the ultra-low temperature infrared photodiode; matching a first simulation result of the first target model with the actual test data; if the match is successful, performing a readout circuit simulation verification based on the first target model to obtain a second simulation result; adjusting the parameters of the first target model according to the matching result of the second simulation result with a preset design condition to obtain a second target model. In the present invention, the temperature parameter is added to the parameters of the ultra-low temperature infrared photodiode equivalent circuit to achieve the establishment of an ultra-low temperature infrared photodiode model under a complete current bias, breaking through the limitation that the low temperature model of commonly used devices only supports -40°C. In the modeling process, the working performance of the ultra-low temperature infrared photodiode in an ultra-low temperature environment is simulated and predicted, and the model parameters are continuously adjusted and optimized based on the simulation results, so as to meet the demand for an accurate ultra-low temperature device model in an ultra-low temperature working environment, which has guiding significance for the circuit design of a refrigerated infrared focal plane imaging readout circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic diagram of the structure of an electronic device in a hardware operating environment involved in an embodiment of the present invention;

[0042] Figure 2 A schematic diagram of a process of an embodiment of a method for modeling an ultra-low temperature infrared photodiode of the present invention;

[0043] Figure 3 This is an example flow chart of ultra-low temperature modeling involved in an embodiment of the present invention;

[0044] Figure 4 This is a schematic diagram of an equivalent circuit of an ultra-low temperature infrared photodiode involved in an embodiment of the present invention;

[0045] Figure 5A schematic diagram showing the comparison between the SPICE model simulation results and the actual test data of the ultra-low temperature infrared photodiode involved in the embodiment of the present invention;

[0046] Figure 6 A simulation schematic diagram of calling an ultra-low temperature infrared photodiode model in Cadence according to an embodiment of the present invention;

[0047] Figure 7 It is a schematic diagram of coupling data verification of the ultra-low temperature infrared photodiode and the transistor M1 involved in the embodiment of the present invention;

[0048] Figure 8 It is a structural block diagram of an embodiment of the ultra-low temperature infrared photodiode modeling system of the present invention.

[0049] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0052] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0053] Reference Figure 1 , Figure 1 The figure is a schematic diagram of the structure of an electronic device of the hardware operating environment involved in the embodiment of the present invention.

[0054] like Figure 1 As shown, the electronic device may include: a processor 1001, such as a central processing unit (CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. Among them, the communication bus 1002 is used to realize the connection and communication between these components. The user interface 1003 may include a display screen (Display), an input unit such as a keyboard (Keyboard), and the optional user interface 1003 may also include a standard wired interface and a wireless interface. The network interface 1004 may optionally include a standard wired interface and a wireless interface (such as a wireless fidelity (Wireless-Fidelity, Wi-Fi) interface). The memory 1005 may be a high-speed random access memory (Random Access Memory, RAM memory) or a stable non-volatile memory (Non-Volatile Memory, NVM), such as a disk memory. The memory 1005 may also be a storage device independent of the aforementioned processor 1001.

[0055] Those skilled in the art will understand that Figure 1 The structure shown in the figure does not constitute a limitation on the electronic device, and may include more or less components than shown in the figure, or combine certain components, or arrange the components differently.

[0056] like Figure 1 As shown, the memory 1005 as a storage medium may include an operating system, a network communication module, a user interface module, and an ultra-low temperature infrared photodiode modeling program.

[0057] exist Figure 1 In the electronic device shown, the network interface 1004 is mainly used for data communication with a network server; the user interface 1003 is mainly used for data interaction with a user; the processor 1001 and the memory 1005 in the electronic device of the present invention can be set in the electronic device, and the electronic device calls the ultra-low temperature infrared photodiode modeling program stored in the memory 1005 through the processor 1001, and executes the ultra-low temperature infrared photodiode modeling method provided in an embodiment of the present invention.

[0058] The present invention provides an ultra-low temperature infrared photodiode modeling method, system and equipment.

[0059] The embodiment of the present invention provides a method for modeling an ultra-low temperature infrared photodiode, referring to Figure 2 , Figure 2 It is a schematic diagram of the flow of an embodiment of the ultra-low temperature infrared photodiode modeling method of the present invention.

[0060] like Figure 2 As shown, the ultra-low temperature infrared photodiode modeling method comprises:

[0061] Step S100: establishing a first target model of an ultra-low temperature infrared photodiode including temperature parameters according to actual test data and an equivalent circuit of the ultra-low temperature infrared photodiode;

[0062] Step S200: matching the first simulation result of the first target model with the actual test data;

[0063] Step S300: If the match is successful, a readout circuit simulation verification is performed based on the first target model to obtain a second simulation result;

[0064] Step S400: adjusting the parameters of the first target model according to the matching result between the second simulation result and the preset design condition to obtain a second target model.

[0065] It should be noted that the execution subject in this embodiment may be an electronic device, which may be a computer device with data processing functions, or other devices that can achieve the same or similar functions. This embodiment does not limit this. In this embodiment, a computer device is used as an example for explanation.

[0066] In one embodiment, a first target model of an ultra-low temperature infrared photodiode including temperature parameters is established based on actual test data and an equivalent circuit of the ultra-low temperature infrared photodiode, including: acquiring actual test data of the ultra-low temperature infrared photodiode; generating an HSPICE netlist including temperature parameters based on the equivalent circuit of the ultra-low temperature infrared photodiode and the actual test data; constructing an initial simulation model of the ultra-low temperature infrared photodiode based on the HSPICE netlist including temperature parameters; adjusting the parameters of the initial simulation model according to the simulation results of the initial simulation model to obtain the first target model of the ultra-low temperature infrared photodiode.

[0067] It is understandable that this embodiment is described by taking an infrared detection photodiode associated with a readout circuit of a refrigerated infrared detector as an example. Specifically, actual test data of an ultra-low temperature infrared photodiode is obtained, and the actual test data may be wafer tape-out data. Figure 3 , Analyze data: Analyze whether the actual test data is reasonable and reliable, and whether it can be used to establish the ultra-low temperature infrared photodiode model of this embodiment.

[0068] In one embodiment, reference Figure 4The equivalent circuit of the ultra-low temperature infrared photodiode includes: a photodiode internal series resistor, a differential equivalent resistor and a photodiode junction capacitor; wherein the first end of the differential equivalent resistor is connected to the first end of the photodiode junction capacitor, the second end of the differential equivalent resistor is connected to the second end of the photodiode junction capacitor, and the second end of the differential equivalent resistor is also connected to the photodiode internal series resistor.

[0069] For example, Figure 3 As shown, write the HSPICE netlist to build the photodiode model: According to the ultra-low temperature infrared photodiode equivalent circuit (such as Figure 4 As shown), write an equivalent circuit HSPICE netlist in HSPICE. The HSPICE netlist uses code language to represent all circuit models and configuration information of the circuit models used in the circuit diagram view. The model language used in this embodiment can be SPICE language. Figure 4 As shown in the equivalent circuit diagram of the ultra-low temperature infrared photodiode, Rs is the internal series resistance of the photodiode, Rd is the differential equivalent resistance, which varies with the material and process, and also varies with the bias voltage, and Cj is the junction capacitance of the photodiode, which also varies with the bias voltage.

[0070] In one embodiment, an HSPICE netlist containing temperature parameters is generated according to an equivalent circuit of an ultra-low temperature infrared photodiode and the actual test data, including: determining the internal series resistance of the photodiode and the netlist parameters affecting the photodiode current according to the equivalent circuit of the ultra-low temperature infrared photodiode; adding the temperature parameters to the resistance formula of the internal series resistance of the photodiode and the netlist parameters to obtain the HSPICE netlist of the ultra-low temperature infrared photodiode to achieve ultra-low temperature modeling under full current bias.

[0071] In one example, part of the HSPICE netlist information for an ultra-low temperature infrared photodiode is as follows:

[0072] .temp-138-123-103

[0073] xd1 a10 dnpd

[0074] v1 a10-3

[0075] .dc v1-330.1

[0076] .print dc i(xd1.d1)i(xd1.rd1)

[0077] .print dc par1='abs(i(xd1.d1)+i(xd1.rd1))'

[0078] .subckt dnpd dp1 dn1 area=9E-10pj=0.00012

[0079] rd1 dp1 dn1'abs(min(v(dp1,dn1),0))*……'

[0080] d1 dp1 dn1 ndio area=area pj=pj temp=temp.

[0081] Specifically, based on the above-mentioned ultra-low temperature infrared photodiode HSPICE netlist, according to information such as test data conditions (such as temperature information in the netlist, etc.), the corresponding model parameters are adjusted and corrected multiple times until the target requirements are met, that is, matching fitting is achieved. In the modeling process, by adjusting the resistance formula of the parallel resistor Rd in the equivalent circuit of the ultra-low temperature infrared photodiode, the temperature parameter model of the photodiode is built into the resistance formula of the parallel resistor Rd. By adjusting the above-mentioned model parameters, a photodiode model with a temperature below -100°C can be established (the first target model of the ultra-low temperature infrared photodiode).

[0082] In one embodiment, matching the first simulation result of the first target model with the actual test data includes: performing simulation verification on the first target model to obtain a first simulation result; performing data fitting comparison between the first simulation result and the actual test data to confirm whether the first simulation result matches the actual test data.

[0083] Specifically, Figure 3 As shown, the ultra-low temperature infrared photodiode model (i.e., the first target model) is adjusted, and based on HSPICE simulation verification, the simulation results (first simulation results) are compared with the measured data of the ultra-low temperature infrared photodiode (e.g., actual test data) to confirm whether the simulation results of the ultra-low temperature infrared photodiode model match the measured data.

[0084] For example, Figure 5 As shown, point ( Figure 5 The dots, triangles and diamonds in the middle represent the measured data (actual test data), and the lines ( Figure 5 The solid line, dashed line and dashed dotted line in the figure represent the fitting simulation results. The measured data of the ultra-low temperature infrared photodiode include 135K (-138℃), 150K (-123℃) and 170K (-103℃), and the SPICE fitting model of the ultra-low temperature infrared photodiode (i.e. the first target model) also corresponds to 135K (-138℃), 150K (-123℃) and 170K (-103℃). Figure 5As shown in the figure, from the comparison between the measured data of the ultra-low temperature infrared photodiode and the simulation results of the SPICE model of the ultra-low temperature infrared photodiode, in the key area of ​​the ultra-low temperature infrared photodiode, that is, the -1v to 1v range, the measured data ( Figure 5 The circle, triangle and diamond points) and the model simulation results ( Figure 5 The solid line, dashed line and dashed dotted line in the figure are matched. Figure 3 As shown in the figure, if the model simulation results do not match the measured data, it is necessary to return to step 3 and refit and adjust the model parameters to match them.

[0085] In one embodiment, a readout circuit simulation verification is performed based on the first target model to obtain a second simulation result, including: establishing a first version model of an ultra-low temperature infrared photodiode based on the first target model; establishing a simulation schematic diagram based on Cadence simulation software; and performing a readout circuit simulation verification based on the simulation schematic diagram and the first version model to obtain a second simulation result.

[0086] In one example, Cadence software simulation is used as an example. Figure 3 As shown, after the first match, that is, after checking that the first target model matches the measured data, the ultra-low temperature infrared photodiode SPECTRE version model (i.e., the first version model) can be established. The SPECTRE version model can be used for Cadence software simulation, and then the schematic diagram can be built based on the Cadence IC617 software for simulation verification to obtain the IC617 simulation result (i.e., the second simulation result) for the second match.

[0087] It should be noted that in practical applications, after the first matching, i.e. checking that the first target model matches the measured data, multiple ultra-low temperature infrared photodiode models suitable for different simulation software can be established. For example, Figure 3 As shown, two different versions of models can be established, namely the SPECTRE version model (first version model) and the HSPICE version model (second version model). The SPECTRE version model and the HSPICE version model can set the same model parameters, and different language expressions are used to apply to different simulation software. For example, the HSPICE version model can be used for SPICE software simulation, and the SPECTRE version model can be used for Cadence software simulation. Different versions of the model can be obtained by modifying the first target model, such as adjusting parameters to increase the design margin, etc.

[0088] For example, the HSPICE version of the ultra-low temperature infrared photodiode model structure is as follows:

[0089] .subckt dnpd dp1 dn1 area=9E-10pj=0.00012

[0090] rd1 dp1 dn1'abs(min(v(dp1,dn1),0)) / (1.3402e-13*(temper-25)*(temper-25)+……'

[0091] d1 dp1 dn1 ndio area=area pj=pj temp=temp

[0092] .model ndio d

[0093] +LEVEL=3JS=5E-07JSW=1E-12

[0094] +N='(-1.7027e-2*(temper-25)+……)'

[0095] +RS='6.90476e-8*(temper-25)*(temper-25)……'

[0096] +IKR=1E6 IBV=1000nbv='-1.13514e-2*(temper-25)+……’

[0097] …

[0098] …

[0099] …

[0100] .ends dnpd

[0101] Among them, abs(min(v(dp1,dn1),0)) / (1.3402e-13*(temper-25)*(temper-25)+… is recorded as formula (1).

[0102] For example, the SPECTRE version of the ultra-low temperature infrared photodiode model structure is as follows:

[0103] subckt dnpd(dp1 dn1)

[0104] parameters area=9E-10pj=0.00012trise=0

[0105] rd1(dp1 dn1)resistor

[0106] r=abs(min(v(dp1,dn1),0)) / (1.3402e-13*(temp-25)*(temp-25)+

[0107] …

[0108] d1(dp1 dn1)ndio area=areapj=pj trise=trise

[0109] model ndio diode

[0110] +level=1

[0111] +ibv=1000ik=1e10 ikp=1e6

[0112] +is=5E-7isw=1E-12n=(-1.7027e-2*(temp-25)+……)

[0113] +ns=(-1.7027e-2*(temp-25)+……)

[0114] +rs=6.90476e-8*(temp-25)*(temp-25)+……

[0115] …

[0116] …

[0117] …

[0118] ends dnpd

[0119] In one embodiment, reference Figure 6 , the simulation schematic diagram includes: a plurality of transistor units and an ultra-low temperature infrared photodiode; wherein the transistor unit includes a first transistor M1 and a second transistor M2; the cathode of the ultra-low temperature infrared photodiode Dnpd is connected to the source of the first transistor M1, and the drain of the first transistor M1 is connected to the drain of the second transistor M2.

[0120] In one embodiment, a readout circuit simulation verification is performed according to the simulation schematic and the first version model to obtain a second simulation result, including: substituting the ultra-low temperature infrared photodiode established by the first version model into the simulation schematic for simulation verification; obtaining circuit coupling characteristic data by simulating the coupling characteristics of the ultra-low temperature infrared photodiode and the transistor of the simulation schematic; and using the circuit coupling characteristic data as the second simulation result.

[0121] Specifically, a simulation schematic diagram is established in the simulation software Cadence IC617 (simulation schematic diagram reference Figure 6 ), and call the ultra-low temperature infrared photodiode SPICE model (first version model) for simulation verification. Figure 6 The simulation schematic diagram shown in Figure 6 Dnpd is the ultra-low temperature infrared photodiode modeled in this paper. Figure 6 The transistor M1 and the transistor M2 are shown in FIG. 1 . In practical applications, the readout circuit may include a plurality of transistors arranged in rows and columns. Figure 6 Other structures are omitted.

[0122] For example, a simulation schematic diagram is established in the simulation software Cadence IC617, and the established ultra-low temperature infrared photodiode model is substituted into the following Figure 6 The Cadence simulation result (second simulation result) is obtained by simulating the coupling characteristics of the ultra-low temperature infrared photodiode Dnpd and other devices (such as MOS tube M1). It can be understood that the Cadence simulation verification includes but is not limited to verifying whether the ultra-low temperature infrared photodiode Dnpd can work normally at ultra-low temperature and the coupling characteristics of the ultra-low temperature infrared photodiode Dnpd and other devices such as transistors.

[0123] In one embodiment, the parameters of the first target model are adjusted according to the matching result between the second simulation result and the preset design condition to obtain the second target model.

[0124] Specifically, Figure 3 As shown, by comparing the Cadence simulation results with the design requirements (preset design conditions), it is confirmed whether the simulated current provided by the ultra-low temperature infrared photodiode model can make the circuit work normally at ultra-low temperatures. It should be noted that the preset design conditions include but are not limited to the photocurrent reaching the transistor turn-on range, etc. The specific preset design conditions can be set according to the actual situation, and this embodiment does not limit this.

[0125] Exemplarily, the circuit coupling characteristic data is obtained by simulating the coupling characteristics of the ultra-low temperature infrared photodiode Dnpd and other devices (such as the MOS tube M1). Figure 7 As shown, the simulated circuit coupling characteristic data is compared with the test data, where the test data may be coupling data of ultra-low temperature infrared photodiodes and MOS devices etc. for the designed circuit test.

[0126] Specifically, Figure 3 As shown, according to the comparison results, the model parameters of the ultra-low temperature infrared photodiode are adjusted and further optimized (the parameters of the first target model are adjusted) to ensure that the characteristics of the model more accurately reflect the coupling characteristic data of the circuit, thereby obtaining the second target model, that is, the final ultra-low temperature infrared photodiode model.

[0127] Exemplarily, the ductility of the simulated current and voltage provided by the ultra-low temperature infrared photodiode model in the low temperature direction is determined. If the simulation result is correct (matched), the ultra-low temperature infrared photodiode SPICE model verification is passed, and the modeling and verification process of the ultra-low temperature infrared photodiode SPICE model can be completed. If the simulation result is abnormal, it is necessary to check whether there is a problem with the previous steps, and it is necessary to simulate and verify again.

[0128] It should be noted that the modeling method of the ultra-low temperature infrared photodiode of this embodiment is described below through specific parameter examples:

[0129] Specifically, in the above modeling process, based on Figure 5 The data of the ultra-low temperature infrared photodiode in the ultra-low temperature infrared photodiode are used to adjust the resistance formula (1) of the parallel resistor Rd in the equivalent circuit of the ultra-low temperature infrared photodiode. First, the parameters of the parallel resistor Rd at 150K are extracted using the data of the target temperature 150K. Then, based on Figure 5 The different temperature data of the ultra-low temperature infrared photodiode 135K and 170K are used to build the temperature parameter model of the photodiode in the resistance formula (1) of the parallel resistor Rd. By adjusting the above model parameters, a photodiode model with a temperature below -100°C (the first target model) can be established.

[0130] Formula (1) can be regarded as Rd=R0*(1+k1*(temp-25)+k2*(temp-25)*(temp-25)), where R0 is the resistance of the parallel resistor Rd at 150K (-123°C) based on the IV characteristic data of the photodiode, and R0 is a function of the voltage across the photodiode. By adding the temperature parameters K1 and K2 of the photodiode parallel resistor to the R0 resistance parameter at 150K, adjusting the temperature parameters K1 and K2 of the photodiode parallel resistor can achieve the following: Figure 5 The model of the photodiode at 135K (-138°C) and 170K (-103°C) is established. Exemplarily, formula (1) can be: abs(min(v(dp1,dn1),0)) / (1.3402e-13*(temper-25)*(temper-25)+…'; wherein the temperature parameter K2 is 1.3402e-13, and the temperature parameter K1 is not shown. Here, the specific temperature parameters need to be set and adjusted according to the actual application design requirements, and the specific values ​​of the temperature parameters are not limited in this embodiment.

[0131] Similarly, by adding temperature parameters to the series resistance Rs of the photodiode equivalent circuit and other parameters that affect the photodiode current Id, the establishment of an ultra-low temperature infrared photodiode model under complete current bias can be achieved. Based on such an ultra-low temperature modeling model, the limitation that the low temperature model of common devices only supports -40°C can be broken. The ultra-low temperature infrared photodiode modeling method used in this embodiment can meet the requirements for the ultra-low temperature working characteristics of the photodiode and the accurate ultra-low temperature device model in the ultra-low temperature working environment of the refrigeration type photodiode.

[0132] In addition, the established ultra-low temperature photodiode model is substituted into Figure 6 The simulation is verified in the design circuit (simulation schematic diagram), and the coupling characteristics of the ultra-low temperature photodiode and other devices are simulated and compared with the coupling data of the ultra-low temperature photodiode and MOS devices tested in the design circuit (such as Figure 7 According to the comparison results, the model parameters of the ultra-low temperature photodiode are adjusted and further optimized to ensure that the characteristics of the model more accurately reflect the coupling characteristics of the circuit, which has a good guiding significance for circuit design.

[0133] In this embodiment, by studying the key technical issues of the refrigerated infrared focal plane imaging readout circuit, the HSPICE netlist is used to realize the construction of the ultra-low temperature infrared photodiode equivalent circuit in the model extraction process, and the model parameters are continuously adjusted and optimized based on the HSPICE netlist simulation results. The ultra-low temperature infrared photodiode model is verified in the existing refrigerated focal plane readout circuit, and the simulated current provided by the ultra-low temperature infrared photodiode model is ductile in the low temperature direction. In addition, the coupling characteristics of the ultra-low temperature infrared photodiode and other devices are simulated, and the working performance of the circuit in an ultra-low temperature environment is simulated and predicted by verifying the ultra-low temperature infrared photodiode SPICE model, which has guiding significance for circuit design.

[0134] It can be understood that the ultra-low temperature infrared photodiode modeling method of this embodiment can be supported and applied in all commonly used circuit simulators, EDA software, and modeling software in the industry, and the modeling is convenient, fast, accurate, and the simulation speed is fast, which can further shorten the product design cycle of integrated circuits and reduce costs.

[0135] The present embodiment provides a method for modeling an ultra-low temperature infrared photodiode, including: establishing a first target model of an ultra-low temperature infrared photodiode including temperature parameters according to actual test data and an equivalent circuit of the ultra-low temperature infrared photodiode; matching a first simulation result of the first target model with the actual test data; if the match is successful, performing a readout circuit simulation verification based on the first target model to obtain a second simulation result; adjusting the parameters of the first target model according to the matching result of the second simulation result with the preset design condition to obtain a second target model. In the present embodiment, the temperature parameter is added to the parameters of the ultra-low temperature infrared photodiode equivalent circuit to achieve the establishment of an ultra-low temperature infrared photodiode model under a complete current bias, breaking through the limitation that the low temperature model of the commonly used device only supports -40°C. In the modeling process, the working performance of the ultra-low temperature infrared photodiode in an ultra-low temperature environment is simulated and predicted, and the model parameters are continuously adjusted and optimized based on the simulation results, so as to meet the demand for an accurate ultra-low temperature device model in an ultra-low temperature working environment, which has guiding significance for the circuit design of the refrigerated infrared focal plane imaging readout circuit.

[0136] In addition, an embodiment of the present invention also proposes a storage medium, on which an ultra-low temperature infrared photodiode modeling program is stored. When the ultra-low temperature infrared photodiode modeling program is executed by a processor, the steps of the ultra-low temperature infrared photodiode modeling method described above are implemented.

[0137] Reference Figure 8 , Figure 8 It is a structural block diagram of an embodiment of the ultra-low temperature infrared photodiode modeling system of the present invention.

[0138] like Figure 8 As shown, the ultra-low temperature infrared photodiode modeling system comprises:

[0139] A model building module 10 is used to build a first target model of the ultra-low temperature infrared photodiode including temperature parameters according to actual test data and an equivalent circuit of the ultra-low temperature infrared photodiode;

[0140] A first matching module 20, used for matching a first simulation result of the first target model with the actual test data;

[0141] A coupling simulation module 30, configured to perform a readout circuit simulation verification based on the first target model to obtain a second simulation result if the matching is successful;

[0142] The second matching module 40 is used to adjust the parameters of the first target model according to the matching result between the second simulation result and the preset design condition to obtain the second target model.

[0143] In this embodiment, a temperature parameter is added to the parameters of the ultra-low temperature infrared photodiode equivalent circuit to achieve the establishment of an ultra-low temperature infrared photodiode model under complete current bias, breaking through the limitation that the low temperature model of common devices only supports -40°C. In the modeling process, the working performance of the ultra-low temperature infrared photodiode in an ultra-low temperature environment is simulated and predicted, and the model parameters are continuously adjusted and optimized based on the simulation results, thereby meeting the demand for an accurate ultra-low temperature device model in an ultra-low temperature working environment, which has guiding significance for the circuit design of a refrigerated infrared focal plane imaging readout circuit.

[0144] It should be noted that the technical details that are not described in detail in the embodiment of the ultra-low temperature infrared photodiode modeling system can be found in the ultra-low temperature infrared photodiode modeling method described above provided in any embodiment of the present invention, and will not be repeated here.

[0145] It should be understood that the above is only an example and does not constitute any limitation on the technical solution of the present invention. In specific applications, technicians in this field can make settings as needed, and the present invention does not limit this.

[0146] It should be noted that the workflow described above is merely illustrative and does not limit the scope of protection of the present invention. In practical applications, technicians in this field can select part or all of them according to actual needs to achieve the purpose of the present embodiment, and no limitation is made here.

[0147] In addition, it should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0148] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0149] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as a read-only memory (ROM) / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present invention.

[0150] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for modeling an ultra-low temperature infrared photodiode, characterized in that: include: A first target model of an ultra-low temperature infrared photodiode including temperature parameters is established according to actual test data and an equivalent circuit of the ultra-low temperature infrared photodiode; Matching a first simulation result of the first target model with the actual test data; If the match is successful, performing a readout circuit simulation verification based on the first target model to obtain a second simulation result; According to the matching result between the second simulation result and the preset design condition, the parameters of the first target model are adjusted to obtain the second target model.

2. The method according to claim 1, characterized in that The first target model of the ultra-low temperature infrared photodiode including temperature parameters is established according to the actual test data and equivalent circuit of the ultra-low temperature infrared photodiode, including: Obtain actual test data of ultra-low temperature infrared photodiodes; Generate an HSPICE netlist including temperature parameters according to an equivalent circuit of an ultra-low temperature infrared photodiode and the actual test data; Building an initial simulation model of an ultra-low temperature infrared photodiode based on the HSPICE netlist containing temperature parameters; The parameters of the initial simulation model are adjusted according to the simulation results of the initial simulation model to obtain a first target model of the ultra-low temperature infrared photodiode.

3. The method according to claim 2, characterized in that The equivalent circuit of the ultra-low temperature infrared photodiode includes: a photodiode internal series resistor, a differential equivalent resistor and a photodiode junction capacitor; wherein, The first end of the differential equivalent resistor is connected to the first end of the photodiode junction capacitor, the second end of the differential equivalent resistor is connected to the second end of the photodiode junction capacitor, and the second end of the differential equivalent resistor is also connected to the internal series resistor of the photodiode.

4. The method according to claim 2, characterized in that The generating of the HSPICE netlist including the temperature parameters according to the equivalent circuit of the ultra-low temperature infrared photodiode and the actual test data comprises: Determine the internal series resistance of the photodiode and the netlist parameters that affect the photodiode current based on the equivalent circuit of the ultra-low temperature infrared photodiode; The temperature parameter is added to the resistance formula of the internal series resistance of the photodiode and the netlist parameters to obtain the HSPICE netlist of the ultra-low temperature infrared photodiode to achieve ultra-low temperature modeling under full current bias.

5. The method according to claim 1, characterized in that The matching of the first simulation result of the first target model with the actual test data includes: Performing simulation verification on the first target model to obtain a first simulation result; The first simulation result is compared with the actual test data through data fitting to confirm whether the first simulation result matches the actual test data.

6. The method according to any one of claims 1 to 5, characterized in that The performing readout circuit simulation verification based on the first target model to obtain a second simulation result includes: Establishing a first version model of an ultra-low temperature infrared photodiode based on the first target model; Create simulation schematics based on Cadence simulation software; A readout circuit simulation verification is performed according to the simulation schematic diagram and the first version model to obtain a second simulation result.

7. The method according to claim 6, characterized in that The simulation schematic diagram includes: a plurality of transistor units and an ultra-low temperature infrared photodiode; wherein, The transistor unit includes a first transistor and a second transistor; The cathode of the ultra-low temperature infrared photodiode is connected to the source of the first transistor, and the drain of the first transistor is connected to the drain of the second transistor.

8. The method according to claim 6, characterized in that The performing readout circuit simulation verification according to the simulation schematic diagram and the first version model to obtain a second simulation result includes: Substituting the ultra-low temperature infrared photodiode established by the first version model into the simulation schematic diagram for simulation verification; By simulating the coupling characteristics of the ultra-low temperature infrared photodiode and the transistor of the simulation schematic diagram, circuit coupling characteristic data is obtained; The circuit coupling characteristic data is used as a second simulation result.

9. An ultra-low temperature infrared photodiode modeling system, characterized in that: include: A model building module, used to build a first target model of the ultra-low temperature infrared photodiode including temperature parameters according to actual test data and an equivalent circuit of the ultra-low temperature infrared photodiode; A first matching module, used for matching a first simulation result of the first target model with the actual test data; A coupling simulation module, configured to perform a readout circuit simulation verification based on the first target model to obtain a second simulation result if the matching is successful; The second matching module is used to adjust the parameters of the first target model according to the matching result between the second simulation result and the preset design condition to obtain the second target model.

10. An electronic device, characterized in that: The electronic device includes: a memory, a processor, and an ultra-low temperature infrared photodiode modeling program stored in the memory and executable on the processor, wherein the ultra-low temperature infrared photodiode modeling program is configured to implement the ultra-low temperature infrared photodiode modeling method as described in any one of claims 1 to 8.

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