Method and apparatus for obtaining drain current of gallium nitride high electron mobility transistor
By constructing a method based on Boltzmann distribution and one-dimensional Poisson equation, the drain current function of gallium nitride high electron mobility transistors is obtained, which solves the problem of limited scalability of existing models and realizes accurate description of drain current of GaN HEMT and improves circuit design.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHENGDU UNIV
- Filing Date
- 2026-03-26
- Publication Date
- 2026-05-29
AI Technical Summary
Existing drain current models for gallium nitride high electron mobility transistors (GaN HEMTs) have limited scalability. ASM-HEMT and MVSG models require refitting parameters when changing device geometry and do not conform to the physical nature of the device.
By treating the carriers in the channel of a gallium nitride high electron mobility transistor as an accumulation layer that follows a Boltzmann distribution, the charge density function of the first channel is obtained using the one-dimensional Poisson equation. The charge density function of the second channel is constructed by combining the static electrical characteristic parameters of the device. The surface potential function is solved by approximation to obtain the drain current function. The current function at any point in the channel is constructed in conjunction with the drain current function to determine the voltage and electric field functions near the gate edge. Finally, the drain current is calculated.
It achieves an accurate description of the drain current of GaN HEMT, improves design efficiency and accuracy, is suitable for circuit simulation and design, and overcomes the shortcomings of poor scalability of existing models.
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Figure CN121936394B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor device technology, specifically to a method and apparatus for obtaining the drain current of a gallium nitride high electron mobility transistor. Background Technology
[0002] The drain current model of gallium nitride high electron mobility transistors (GaN HEMTs) quantifies the electrical characteristics of the device, transforming complex physical mechanisms into mathematical expressions suitable for circuit simulation. It serves as a crucial bridge connecting device physics and circuit design. This model is not only the core technological foundation for the engineering application of GaN HEMTs, but also plays a vital role in promoting the integration of GaN technology into standardized design processes.
[0003] In existing technologies, there are two mainstream GaN HEMT drain current models: the Advanced Integrated Circuit Simulation Model for High Electron Mobility Transistors (ASM-HEMT) and the MIT Virtual Source GaN Field-Effect Transistor Compact Model (MVSG). The ASM-HEMT model, which uses coupled solutions to the Schrödinger and Poisson equations to calculate the surface potential, is somewhat complex. Furthermore, the ASM-HEMT model uses empirical formulas to calculate the saturation voltage, requiring refitting of relevant parameters when changing the device geometry, thus limiting its scalability. The MVSG model uses empirical formulas to calculate the channel carrier density and the drain current from the linear to the nonlinear region. The resistance of the source and drain access regions is controlled by a virtual gate, which does not conform to the physical nature of the device, thus also limiting its scalability. Summary of the Invention
[0004] The purpose of this application is to provide a method and apparatus for obtaining the drain current of a gallium nitride high electron mobility transistor, which solves the technical problem of limited scalability of the prior art.
[0005] This application is achieved through the following technical solution:
[0006] The first aspect of this application provides a method for obtaining the drain current of a gallium nitride high electron mobility transistor, including:
[0007] The carriers in the channel of the gallium nitride high electron mobility transistor are regarded as an accumulation layer and follow a Boltzmann distribution. The carrier charge density function of the first channel is obtained by the one-dimensional Poisson equation.
[0008] Based on the static electrical characteristics of gallium nitride high electron mobility transistors, a second-channel carrier charge density function is constructed.
[0009] The surface potential function is obtained by jointly approximating the first channel carrier charge density function and the second channel carrier charge density function, and the drain current function is obtained based on the surface potential function.
[0010] Construct the current function at any point in the channel, and solve the current function at any point in the channel together with the drain current function to obtain the electric field function at the gate edge near the drain.
[0011] Construct a source access region current expression function, and combine the source access region current expression function with the drain current function to determine the target voltage correlation function between the voltage at the gate edge of the adjacent source and the voltage at the gate edge of the adjacent drain.
[0012] The target voltage correlation function and the electric field function at the gate edge of the adjacent drain are solved together to determine the voltage at the gate edge of the adjacent source and the voltage at the gate edge of the adjacent drain.
[0013] The drain current of the gallium nitride high electron mobility transistor is obtained by calling the drain current function based on the solved values of the voltage at the gate edge of the adjacent source and the gate edge of the adjacent drain.
[0014] In one possible implementation, the carriers in the channel of a gallium nitride high electron mobility transistor are considered as an accumulation layer and follow a Boltzmann distribution. The carrier charge density function of the first channel is obtained through the one-dimensional Poisson equation, including:
[0015] Obtain the elementary charge, device temperature, preset doping concentration, and dielectric constant;
[0016] The carriers in the channel of a gallium nitride high electron mobility transistor are considered as an accumulation layer and follow a Boltzmann distribution. Based on the elementary charge, device temperature, preset doping concentration, and dielectric constant, a one-dimensional Poisson equation is used to obtain the relationship function between the surface potential and the channel carrier charge density, thus obtaining the first channel carrier charge density function.
[0017] In one possible implementation, based on the static electrical characteristics of gallium nitride high electron mobility transistors, a second channel carrier charge density function is constructed, including:
[0018] The turn-off voltage, gate voltage, and barrier layer capacitance of the gallium nitride high electron mobility transistor were obtained to obtain the static electrical characteristic parameters of the gallium nitride high electron mobility transistor.
[0019] Based on the static electrical characteristics of the gallium nitride high electron mobility transistor, a relationship function between surface potential and channel carrier charge density is constructed to obtain the second channel carrier charge density function.
[0020] In one possible implementation, the surface potential function is obtained by jointly approximating the first channel carrier charge density function and the second channel carrier charge density function, including:
[0021] The surface potential function is obtained by jointly approximating the first channel carrier charge density function and the second channel carrier charge density function using the Halley method.
[0022] In one possible implementation, obtaining the drain current function based on the surface potential function includes:
[0023] The elementary charge and device temperature are obtained, and the thermal voltage is obtained based on the elementary charge and device temperature, combined with the Boltzmann constant.
[0024] The overdrive voltage is obtained, and the first intermediate voltage is obtained based on the overdrive voltage, the surface potential function, and the first voltage parameter.
[0025] Based on the first intermediate voltage, establish the relationship function between the voltage at the gate edge near the source, the voltage at the gate edge near the drain, and the drain current to obtain the drain current function.
[0026] In one possible implementation, a current function at any point in the channel is constructed, and the current function at any point in the channel is jointly solved with the drain current function to obtain the electric field function at the gate edge adjacent to the drain, including:
[0027] Construct the current function at any point in the channel, and solve the current function at any point in the channel together with the drain current function to obtain the potential function at any point in the channel;
[0028] Differentiating the potential function at any point in the channel yields the electric field function at the gate edge near the drain.
[0029] In one possible implementation, a source access region current expression function is constructed, and the source access region current expression function is combined with the drain current function to determine a target voltage correlation function between the voltage at the gate edge adjacent to the source and the voltage at the gate edge adjacent to the drain, including:
[0030] Construct a source access region current expression function, and make the source access region current in the source access region current expression function equal to the drain current in the drain current function, so as to combine the source access region current expression function and the drain current function into a single function, and obtain the target voltage correlation function between the voltage at the gate edge of the adjacent source and the voltage at the gate edge of the adjacent drain.
[0031] In one possible implementation, the target voltage correlation function is jointly solved with the electric field function at the gate edge of the adjacent drain to determine the solved values of the voltage at the gate edge of the adjacent source and the voltage at the gate edge of the adjacent drain, including:
[0032] According to the target voltage correlation function, the voltage at the gate edge of the source electrode in the electric field function at the gate edge of the adjacent drain electrode is completely converted into the voltage at the gate edge of the adjacent drain electrode, thus obtaining the converted electric field function at the gate edge.
[0033] When the electric field at the gate edge reaches the critical electric field, the solution value of the voltage at the gate edge adjacent to the drain is obtained;
[0034] Based on the solution value of the voltage at the gate edge of the adjacent drain, the solution value of the voltage at the gate edge of the adjacent source is obtained by using the target voltage correlation function.
[0035] In one possible implementation, the drain current of the gallium nitride high electron mobility transistor is obtained by calling a drain current function based on the solved values of the voltage at the gate edge adjacent to the source and the gate edge adjacent to the drain, including:
[0036] The solution values of the voltage at the gate edge of the adjacent source and the voltage at the gate edge of the adjacent drain are input into the drain current function to obtain the drain current of the gallium nitride high electron mobility transistor.
[0037] The first aspect of this application provides a drain current acquisition device for a gallium nitride high electron mobility transistor, comprising:
[0038] The first charge density function acquisition module is used to treat the carriers in the channel of the gallium nitride high electron mobility transistor as an accumulation layer and obey the Boltzmann distribution, and to obtain the first channel carrier charge density function through the one-dimensional Poisson equation.
[0039] The second charge density function acquisition module is used to construct the second channel carrier charge density function based on the static electrical characteristic parameters of the gallium nitride high electron mobility transistor.
[0040] The drain current function acquisition module is used to jointly approximate the first channel carrier charge density function and the second channel carrier charge density function to obtain the surface potential function, and obtain the drain current function based on the surface potential function.
[0041] The electric field function acquisition module is used to construct the current function at any point in the channel and jointly solve the current function at any point in the channel with the drain current function to obtain the electric field function at the gate edge adjacent to the drain.
[0042] The target voltage correlation function acquisition module is used to construct the source access region current expression function and combine the source access region current expression function with the drain current function to determine the target voltage correlation function between the voltage at the gate edge of the adjacent source and the voltage at the gate edge of the adjacent drain.
[0043] The voltage solving module is used to jointly solve the target voltage correlation function and the electric field function at the gate edge of the adjacent drain to determine the solved value of the voltage at the gate edge of the adjacent source and the solved value of the voltage at the gate edge of the adjacent drain.
[0044] The drain current calculation module is used to obtain the drain current of the gallium nitride high electron mobility transistor by calling the drain current function based on the calculated values of the voltage at the gate edge of the adjacent source and the gate edge of the adjacent drain.
[0045] Compared with the prior art, this application has the following advantages and beneficial effects:
[0046] This application provides a method and apparatus for obtaining the drain current of a gallium nitride high electron mobility transistor (GaN HEMT). First, the channel carriers are considered as an accumulation layer following a Boltzmann distribution. The charge density function of the first channel carrier is obtained through the one-dimensional Poisson equation, and the charge density function of the second channel carrier is constructed by combining the device's static electrical characteristic parameters. The drain current function is obtained through a joint approximation solution. Then, the current function at any point in the channel is constructed and solved simultaneously with the drain current function to obtain the electric field function at the gate edge adjacent to the drain. Simultaneously, the target voltage correlation function is determined by combining the source access region current expression function. The voltage values at the gate edges adjacent to the source and drain are then obtained through a joint solution. Finally, the drain current is calculated based on the two solution values. This method, combining physics and computation, effectively overcomes the shortcomings of existing models in terms of poor scalability and is suitable for circuit simulation and design of GaN HEMTs. Attached Figure Description
[0047] To more clearly illustrate the technical solutions of the exemplary embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:
[0048] Figure 1 A flowchart illustrating a method for obtaining the drain current of a gallium nitride high electron mobility transistor, provided as an embodiment of this application;
[0049] Figure 2This is a schematic diagram of the basic structure of a gallium nitride high electron mobility transistor provided in an embodiment of this application;
[0050] Figure 3 A schematic diagram comparing the surface potential obtained using the exact numerical solution method and the Halley method, provided in an embodiment of this application;
[0051] Figure 4(a) is a schematic diagram of the simulation results of a long-channel device provided in an embodiment of this application, and Figure 4(b) is a schematic diagram of the simulation results of another long-channel device provided in an embodiment of this application;
[0052] Figure 5(a) is a schematic diagram of the simulation results of a short-channel device provided in an embodiment of this application, and Figure 5(b) is a schematic diagram of the simulation results of another short-channel device provided in an embodiment of this application.
[0053] Figure 6 A schematic diagram of the simulation results of the device with field plate structure provided in the embodiments of this application;
[0054] Figure 7 A schematic diagram of the drain current acquisition device of a gallium nitride high electron mobility transistor provided in an embodiment of this application;
[0055] Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application;
[0056] The attached diagram shows the markings and corresponding component names:
[0057] 701-First charge density function acquisition module, 702-Second charge density function acquisition module, 703-Drain current function acquisition module, 704-Electric field function acquisition module, 705-Target voltage correlation function acquisition module, 706-Voltage solving module, 707-Drain current solving module, 801-Memory, 802-Processor, 803-Bus. Detailed Implementation
[0058] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this application are only for explaining this application and are not intended to limit this application.
[0059] like Figure 1 As shown in the figure, this application provides a method for obtaining the drain current of a gallium nitride high electron mobility transistor, including:
[0060] S101. The carriers in the channel of the gallium nitride high electron mobility transistor are regarded as an accumulation layer and follow the Boltzmann distribution. The carrier charge density function of the first channel is obtained by the one-dimensional Poisson equation.
[0061] S102. Based on the static electrical characteristics parameters of gallium nitride high electron mobility transistors, construct the carrier charge density function of the second channel;
[0062] S103. The first channel carrier charge density function and the second channel carrier charge density function are jointly approximated to obtain the surface potential function, and the drain current function is obtained based on the surface potential function.
[0063] S104. Construct the current function at any point in the channel, and solve the current function at any point in the channel together with the drain current function to obtain the electric field function at the gate edge near the drain.
[0064] S105. Construct a source access region current expression function, and combine the source access region current expression function with the drain current function to determine the target voltage correlation function between the voltage at the gate edge of the adjacent source and the voltage at the gate edge of the adjacent drain.
[0065] S106. Solve the target voltage correlation function together with the electric field function at the gate edge of the adjacent drain to determine the solution value of the voltage at the gate edge of the adjacent source and the solution value of the voltage at the gate edge of the adjacent drain.
[0066] S107. Based on the solved value of the voltage at the gate edge of the adjacent source and the solved value of the voltage at the gate edge of the adjacent drain, the drain current function is called to obtain the drain current of the gallium nitride high electron mobility transistor.
[0067] The drain current acquisition method for gallium nitride high electron mobility transistors provided in this application can describe the drain current of GaN HEMTs relatively accurately, and has good scalability, which can improve the design efficiency and accuracy of GaN HEMTs and related integrated circuits.
[0068] like Figure 2 As shown, to facilitate a better understanding of the technical solutions described in the embodiments of this application by those skilled in the art, the embodiments of this application provide a basic structural schematic diagram of a gallium nitride high electron mobility transistor. Figure 2 In the basic structure shown, a gallium nitride high electron mobility transistor may include a source, a gate, a field plate, a dielectric, a barrier layer, a drain, and gallium nitride. Figure 2 In The voltage at the source is... This is the voltage at the gate edge near the source. This is the voltage at the gate edge adjacent to the drain. This is the voltage between the drain and source. Drain voltage The length of the source access region. For gate length, The length of the field plate, This is the length between the edge of the field plate and the drain electrode.
[0069] In one possible implementation, the carriers in the channel of a gallium nitride high electron mobility transistor are considered as an accumulation layer and follow a Boltzmann distribution. The carrier charge density function of the first channel is obtained through the one-dimensional Poisson equation, including:
[0070] Obtain the elementary charge, device temperature, preset doping concentration, and dielectric constant;
[0071] The carriers in the channel of a gallium nitride high electron mobility transistor are considered as an accumulation layer and follow a Boltzmann distribution. Based on the elementary charge, device temperature, preset doping concentration, and dielectric constant, a one-dimensional Poisson equation is used to obtain the relationship function between the surface potential and the channel carrier charge density, thus obtaining the first channel carrier charge density function.
[0072] For example, if the carriers in the channel of a gallium nitride high electron mobility transistor are considered as an accumulation layer and follow a Boltzmann distribution, the carrier charge density function of the first channel can be obtained by solving the one-dimensional Poisson equation under the condition that the drain voltage is 0:
[0073] (1);
[0074] In the formula, The channel carrier charge density, The preset doping concentration, For Debye length, and ; The dielectric constant of gallium nitride in gallium nitride high electron mobility transistors. Boltzmann's constant, For device temperature, For elementary charge, Let be the surface potential, and e be the natural constant.
[0075] In one possible implementation, based on the static electrical characteristics of gallium nitride high electron mobility transistors, a second channel carrier charge density function is constructed, including:
[0076] The turn-off voltage, gate voltage, and barrier layer capacitance of the gallium nitride high electron mobility transistor were obtained to obtain the static electrical characteristic parameters of the gallium nitride high electron mobility transistor.
[0077] Based on the static electrical characteristics of the gallium nitride high electron mobility transistor, a relationship function between surface potential and channel carrier charge density is constructed to obtain the second channel carrier charge density function.
[0078] For example, the turn-off voltage of a gallium nitride high electron mobility transistor can be expressed as: Gate voltage is expressed as And the barrier layer capacitance is expressed as ; This represents the dielectric constant of the barrier layer in a gallium nitride high electron mobility transistor. The thickness of the barrier layer.
[0079] With a drain voltage of 0, the second-channel carrier charge density function can be obtained from the static electrical characteristics of the gallium nitride high electron mobility transistor as follows:
[0080] (2);
[0081] In one possible implementation, the surface potential function is obtained by jointly approximating the first channel carrier charge density function and the second channel carrier charge density function, including:
[0082] The surface potential function is obtained by jointly approximating the first channel carrier charge density function and the second channel carrier charge density function using the Halley method.
[0083] For example, the surface potential function can be:
[0084] (3);
[0085] In the formula, As the first intermediate parameter, As the second intermediate parameter, As the third intermediate parameter, The fourth intermediate parameter, Overdrive voltage, This is the fifth intermediate parameter.
[0086] like Figure 3 As shown, the surface potential obtained using the exact numerical solution method and the Halley method is demonstrated. It can be determined that the results obtained by the two methods are in good agreement. The Halley method not only has higher accuracy but also faster calculation speed and stronger adaptability.
[0087] In one possible implementation, obtaining the drain current function based on the surface potential function includes:
[0088] The elementary charge and device temperature are obtained, and the thermal voltage is obtained based on the elementary charge and device temperature, combined with the Boltzmann constant.
[0089] The overdrive voltage is obtained, and the first intermediate voltage is obtained based on the overdrive voltage, the surface potential function, and the first voltage parameter.
[0090] Based on the first intermediate voltage, establish the relationship function between the voltage at the gate edge near the source, the voltage at the gate edge near the drain, and the drain current to obtain the drain current function.
[0091] Conventional gallium nitride high electron mobility transistors contain access regions for the source and drain. Assuming the voltage at the gate edge adjacent to the source is... and the voltage at the gate edge adjacent to the drain is If a gallium nitride high electron mobility transistor (GaN HEPMT) operates in the linear region, the change in surface potential along the channel with respect to the drain voltage is negligible. If a GaN HEPMT operates in the saturation region, for common gate lengths, the electron velocity will reach saturation at the gate edge near the drain, so the change in surface potential along the channel is also negligible. To reduce computational complexity, the surface potential is expressed by equation (3) at V. DS When = 0, only one calculation is needed. Therefore, the asymptotic channel approximation is used to calculate the drain current, and the drain current function is obtained as follows:
[0092] (4);
[0093] In the formula, This is a function of the drain current. The gate width, For gate length, For electron mobility, This is the barrier layer capacitance. This is the first intermediate voltage. ; ; Overdrive voltage, Thermoelectric voltage;
[0094] If we consider the variation of surface potential along the channel (which may be required for longer channels), then the surface potential needs to be calculated separately at the gate edges adjacent to the source and drain. This can then be approximated using the asymptotic channel approximation. It simply involves calculating the surface potential one more time.
[0095] Electron mobility is obtained using the following model:
[0096] (5);
[0097] In the formula, This is the critical electric field at which electron velocity saturation occurs. The transverse electric field in the channel, and ; for The fitting parameters. , The saturation rate is affected by device temperature;
[0098] The mobility is related to device temperature and longitudinal electric field, and is expressed as:
[0099] (6);
[0100] In the formula, for The first fitting parameter, for The second fitting parameter, For the longitudinal electric field correlation parameters, and ;
[0101] Let be the mobility affected by device temperature, and express it as:
[0102] (7);
[0103] In the formula, Low field mobility at room temperature for Fitting parameters, T represents the ambient temperature, and T represents the device temperature.
[0104] The saturation rate affected by device temperature can be expressed as:
[0105] (8)
[0106] In the formula, The saturation rate at room temperature. for For the access regions of the source and drain, when calculating the mobility using the function shown in the above formula (6), the transverse electric field of the corresponding region needs to be calculated.
[0107] In one possible implementation, a current function at any point in the channel is constructed, and the current function at any point in the channel is jointly solved with the drain current function to obtain the electric field function at the gate edge adjacent to the drain, including:
[0108] Construct the current function at any point in the channel, and solve the current function at any point in the channel together with the drain current function to obtain the potential function at any point in the channel;
[0109] Differentiating the potential function at any point in the channel yields the electric field function at the gate edge near the drain.
[0110] For example, based on the principle of formula (4), the current function at any point in the channel can be constructed as follows:
[0111] (9);
[0112] In the formula, Let the current be at any point. The gate width, Let represent the lateral coordinates of any point within the channel. For the barrier layer capacitance;
[0113] Because of the continuity of current in the channel, therefore = We can solve formulas (4) and (9) together to get:
[0114] (10);
[0115] Then, according to formula (9), the electric field function at the gate edge near the drain is obtained as follows:
[0116] (11);
[0117] In the formula, d represents the electric field at the gate edge near the drain, where d is the differential symbol.
[0118] In one possible implementation, a source access region current expression function is constructed, and the source access region current expression function is combined with the drain current function to determine a target voltage correlation function between the voltage at the gate edge adjacent to the source and the voltage at the gate edge adjacent to the drain, including:
[0119] Construct a source access region current expression function, and make the source access region current in the source access region current expression function equal to the drain current in the drain current function, so as to combine the source access region current expression function and the drain current function into a single function, and obtain the target voltage correlation function between the voltage at the gate edge of the adjacent source and the voltage at the gate edge of the adjacent drain.
[0120] For example, when the electric field at the gate edge adjacent to the drain reaches the critical electric field (i.e. , (This is the critical electric field), where the electron velocity at the gate edge near the drain electrode reaches saturation, thus I DS The drain begins to enter the saturation region. Based on this condition, the drain saturation voltage can be calculated as follows: Therefore, under normal circumstances, The analytical expression cannot be obtained directly. This application will use the following method to obtain... First, we will temporarily disregard the drain access region, i.e., the length L of this drain access region. GD =0, representing the electron mobility in the source access region and the channel as unknown constants. and Since they are independent of the channel electric field, the source access region current expression function can be:
[0121] (12)
[0122] In the formula, For the source access region current, The electron surface density in the source access region. The length of the source access region;
[0123] Combining formulas (4) and (12), that is... You can get and The relationship between them, that is, the target voltage correlation function between the voltage at the gate edge near the source and the voltage at the gate edge near the drain, is:
[0124] (13);
[0125] In the formula, This is the second intermediate voltage.
[0126] In one possible implementation, the target voltage correlation function is jointly solved with the electric field function at the gate edge of the adjacent drain to determine the solved values of the voltage at the gate edge of the adjacent source and the voltage at the gate edge of the adjacent drain, including:
[0127] According to the target voltage correlation function, the voltage at the gate edge of the source electrode in the electric field function at the gate edge of the adjacent drain electrode is completely converted into the voltage at the gate edge of the adjacent drain electrode, thus obtaining the converted electric field function at the gate edge.
[0128] When the electric field at the gate edge reaches the critical electric field, the solution value of the voltage at the gate edge adjacent to the drain is obtained;
[0129] Based on the solution value of the voltage at the gate edge of the adjacent drain, the solution value of the voltage at the gate edge of the adjacent source is obtained by using the target voltage correlation function.
[0130] For example, formula (13) can be substituted into formula (11) and solved. time That is, the voltage at the gate edge near the drain, which can be expressed as:
[0131] (14);
[0132] In the formula, This is the solution value for the voltage at the gate edge adjacent to the drain. The sixth intermediate parameter, The seventh intermediate parameter, This is the third intermediate voltage. This is the fourth intermediate voltage.
[0133] After obtaining the solution value of the voltage at the gate edge near the drain, the solution value of the voltage at the gate edge near the drain can be substituted into formula (13) to obtain the solution value of the voltage at the gate edge near the source when the device reaches the saturation region. .
[0134] In one possible implementation, the drain current of the gallium nitride high electron mobility transistor is obtained by calling a drain current function based on the solved values of the voltage at the gate edge adjacent to the source and the gate edge adjacent to the drain, including:
[0135] The solution values of the voltage at the gate edge of the adjacent source and the voltage at the gate edge of the adjacent drain are input into the drain current function to obtain the drain current of the gallium nitride high electron mobility transistor.
[0136] Under normal circumstances, the source access region and the drain access region Since their currents should be equal, and their mobilities are also equal, we can conclude that their mobilities are equal. Therefore, the mobility of electrons in the drain access region can also be expressed as... In terms of mobility and Under equal conditions, the potential difference between the drain and source access regions is proportional to their respective lengths. Therefore, while ensuring... Under the condition that it includes the missing connection area, its potential difference can be expressed as: (Assuming the source potential is 0). Furthermore, the potential difference in the drain connection region can be added to the equation... The result obtained from You can get , is represented as:
[0137] (15);
[0138] In the formula, This is the drain saturation voltage. This is the length of the drain access region.
[0139] If we consider that the drain access region and the source access region have different characteristics... Therefore, their electron mobilities are not equal. The mobility of the drain access region is expressed as... Then the potential difference in the area where the ground drain electrode is connected is Furthermore, the device's... can also be obtained according to formula (15). .
[0140] If a gallium nitride high electron mobility transistor contains a field plate extending towards the drain (e.g.) Figure 2 As shown), the calculation method for the current under the field plate is the same as the calculation method for the channel current shown in formula (4), except that the field plate has different turn-off voltages and different capacitances. If the capacitance of the field plate is Then its turn-off voltage is expressed as If the length of the plate is The length of the drain access region (i.e., the length between the edge of the field plate and the drain) when there is a field plate is expressed as: Similar to the above method, first calculate the value of the product using formulas (13) and (15). time and Further calculations can be performed to find out In the case of a field plate, the drain saturation voltage is:
[0141] (16)
[0142] In the formula, V FS This is the drain saturation voltage when there is a field plate. This is the fifth intermediate voltage. The surface potential under the field plate. This represents the electron mobility under the field plate.
[0143] In the case of including the drain access region (i.e.) (Not equal to 0), then the drain saturation voltage of the field plate is expressed as: The specific calculation formula is as follows:
[0144] (17);
[0145] If the device contains a second or more field plates, the same method described above can be used to obtain the corresponding results. .
[0146] As mentioned above, The calculations are obtained under the assumption that the electron mobility is an unknown constant. The following method can be used to include the mobility against... The specific impacts are as follows:
[0147] 1) Assuming that the mobility of the source access region, channel, under-field plate (if any), and drain access region of the device are equal, this can also be directly assumed. Using formula - An initial one can be calculated. , , , ;
[0148] 2) Calculate the corresponding transverse electric field in each of the above regions. , respectively represented as ;
[0149] 3) Substitute these transverse electric fields into the expression for mobility. The actual migration rate in each corresponding region can be calculated. , , , ;
[0150] 4) Substitute these actual mobility rates into the formula or Recalculate the drain saturation voltage (correcting the initial drain saturation voltage) to obtain the final value that includes the influence of mobility. or .
[0151] In order to make I DS A smooth transition to the saturation region, for any application applied to the device. (i.e., drain voltage), the actual applied voltage used in the model calculations is called the effective voltage. The parameter, namely:
[0152] (18);
[0153] In the formula, The sixth intermediate voltage, For smoothing parameters. If the device contains a field plate, then in the above formula... Need to be replaced with .
[0154] The current in the drain region can be expressed as:
[0155] (19);
[0156] In the formula, I A This is the current in the drain connection region. The length between the gate and the drain. The width of the gate.
[0157] Since the currents in the drain and source regions should be equal, the current in the source region is also I. A Furthermore, considering that the electron surface density of the drain access region and the source access region are equal, the electron surface density of the source access region is also Q.A .
[0158] To apply this method in actual circuit simulations, it's necessary to consider the self-heating effect and short-channel effect commonly found in gallium nitride high electron mobility transistors (GaN transistors). When the self-heating effect is included, the device has a temperature-dependent nonlinear thermal resistance, expressed as:
[0159] (20);
[0160] in, For temperature-dependent nonlinear thermal resistance, The thermal resistance of the device at ambient temperature. for The fitting parameters. The thermal resistance of the device affects the device temperature (the device temperature usually refers to the channel temperature), which in turn affects the electron mobility and saturation velocity in formulas (7) and (8).
[0161] The short-channel effect mainly includes drain-induced barrier reduction (DIBL) and channel modulation (CLM). When DIBL is included, the turn-off voltage is expressed as... It will follow and Change, that is:
[0162] (twenty one);
[0163] In the formula, for The fitting parameters. Describes the change in turn-off voltage with V DS The increase of I leads to a decrease, thus causing I to decrease in the saturation region. DS Will follow V DS It increased due to the increase in [something].
[0164] When the CLM is included, the drain current is expressed as ,Right now:
[0165] (twenty two);
[0166] In the formula, for The fitting parameters.
[0167] The above method was written into Verilog-A code, mainly including the calculation of currents in the source access region, intrinsic devices, drain access region, and field plate region. The calculation involves setting circuit nodes in these corresponding regions. If a self-heating effect simulation is to be performed, an additional circuit node is needed to represent the temperature. This Verilog-A code can be called in the circuit simulator to simulate gallium nitride high electron mobility transistors and related integrated circuits. Specifically, in the circuit simulator, after applying the drain voltage and gate voltage to the device port, the drain saturation voltage of the device without a field plate can be obtained by equation (15). Substituting the drain voltage and drain saturation voltage into equation (18) can yield the effective voltage. According to the current equality expressed by equations (4), (12), and (19) (the principle of current continuity), the circuit simulator can solve these three equations by numerical iteration to simultaneously obtain the voltage at the gate edge of the adjacent source and the voltage at the gate edge of the adjacent drain, and calculate the drain current according to equation (4). If the device contains a field plate, the drain current can be obtained by expressing the current under the field plate according to equation (4) and the drain saturation voltage with the field plate according to equation (17) in the same way as above.
[0168] To verify the correctness of the model established in this application, the simulation results of using the model to measure the drain current of a typical gallium nitride high electron mobility transistor will be presented below, and compared with the published experimental results.
[0169] Figures 4(a) and 4(b) show the simulation results including the self-heating effect, where the device geometry is as follows:
[0170] Figure 4(a): L SG =1.5μm, L G =1.5μm, L GD =3μm; Figure 4(b): L SG =3μm, L G =1.5μm, L GD =1.5μm, and the potential layer thickness of both devices is 15 nm. Due to the large channel length of the devices, the short-channel effect is not considered in the model. To verify the scalability of the model, Figure 4(b) shows that while keeping the model parameters unchanged, only the geometric dimensions of the devices (its L) are adjusted. SG and L GD Compared with L in Figure 4(a) respectively GD and L SG (Equal). The simulation results agree well with the experimental data in the existing technology, indicating that the model has high accuracy and good scalability.
[0171] Figures 5(a) and (b) simultaneously consider both self-heating effects and short-channel effects (including DIBL and CLM), primarily due to the short channel length of the devices. The device dimensions are as follows:
[0172] Figure 5(a): LSG =1μm, L G =0.35μm, L GD =3μm, barrier layer thickness is 30nm; Figure 5(b): L SG =1.25μm, L G =0.125μm, L GD The gate diameter is 1 μm, and the barrier layer thickness is 12.5 nm. As can be seen from the figure, the short-channel effect is significant under low gate voltage conditions. The simulation results agree well with experimental data in existing technologies, further validating the effectiveness of the model.
[0173] Figure 6 Simulation results of a device with a field plate structure are presented, taking into account the self-heating effect. The device dimensions are: L SG =3μm, L G =2μm, L GD =15μm, L F =2μm, barrier layer thickness 23nm. Due to the relatively long gate of this device, short-channel effects were not introduced into the model. The simulation results are basically consistent with the experimental data provided by existing technologies, indicating that the model also has good predictive ability for this type of structure.
[0174] like Figure 7 As shown, based on the same inventive concept, this application also provides a drain current acquisition device for a gallium nitride high electron mobility transistor, comprising:
[0175] The first charge density function acquisition module 701 is used to treat the carriers in the channel of the gallium nitride high electron mobility transistor as an accumulation layer and obey the Boltzmann distribution, and to obtain the first channel carrier charge density function through the one-dimensional Poisson equation.
[0176] The second charge density function acquisition module 702 is used to construct the second channel carrier charge density function based on the static electrical characteristic parameters of the gallium nitride high electron mobility transistor.
[0177] The drain current function acquisition module 703 is used to jointly approximate the first channel carrier charge density function and the second channel carrier charge density function to obtain the surface potential function, and obtain the drain current function based on the surface potential function.
[0178] The electric field function acquisition module 704 is used to construct the current function at any point in the channel and jointly solve the current function at any point in the channel with the drain current function to obtain the electric field function at the gate edge adjacent to the drain.
[0179] The target voltage correlation function acquisition module 705 is used to construct the source access region current expression function and combine the source access region current expression function with the drain current function to determine the target voltage correlation function between the voltage at the gate edge of the adjacent source and the voltage at the gate edge of the adjacent drain.
[0180] The voltage solving module 706 is used to jointly solve the target voltage correlation function and the electric field function at the gate edge of the adjacent drain to determine the solved value of the voltage at the gate edge of the adjacent source and the solved value of the voltage at the gate edge of the adjacent drain.
[0181] The drain current calculation module 707 is used to obtain the drain current of the gallium nitride high electron mobility transistor by calling the drain current function based on the calculated value of the voltage at the gate edge of the adjacent source and the calculated value of the voltage at the gate edge of the adjacent drain.
[0182] The drain current acquisition device for a gallium nitride high electron mobility transistor provided in this application embodiment can perform the above-described method and technical solution. Its principle and beneficial effects are similar, and will not be repeated here.
[0183] like Figure 8 As shown, based on the same inventive concept, this application also provides an electronic device, including a processor 802 and a memory 801; the memory 801 and the processor 802 are interconnected via a bus 803.
[0184] The memory 801 stores computer-executed instructions;
[0185] The processor 802 executes the computer execution instructions stored in the memory 801, causing the processor 802 to perform a method for obtaining the drain current of a gallium nitride high electron mobility transistor as described in any embodiment of this application.
[0186] For specific examples, memory may include, but is not limited to, random access memory (RAM), read-only memory (ROM), flash memory, first-in-first-out (FIFO) memory, and / or first-in-last-out (FILO) memory, etc.; specifically, processor may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor may be implemented using at least one hardware form of DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), PLA (Programmable Logic Array). Furthermore, the processor may include a main processor and coprocessors. The main processor, also known as the CPU (Central Processing Unit), is used to process data in the wake-up state; the coprocessor is a low-power processor used to process data in the standby state.
[0187] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the drain current acquisition method of gallium nitride high electron mobility transistors described in any of the above embodiments.
[0188] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the drain current acquisition method of gallium nitride high electron mobility transistors as described in any of the above embodiments.
[0189] All or part of the steps in the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a readable memory. When the program is executed, it performs the steps of the above method embodiments; and the aforementioned memory (storage medium) includes: read-only memory (ROM), RAM, flash memory, hard disk, solid-state drive, magnetic tape, floppy disk, optical disk, and any combination thereof.
[0190] This application describes embodiments with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processing unit of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processing unit of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.
[0191] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.
[0192] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.
[0193] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the claims.
[0194] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.
Claims
1. A method for obtaining the drain current of a gallium nitride high electron mobility transistor, characterized in that, include: The carriers in the channel of the gallium nitride high electron mobility transistor are regarded as an accumulation layer and follow a Boltzmann distribution. The carrier charge density function of the first channel is obtained by the one-dimensional Poisson equation. Based on the static electrical characteristics of gallium nitride high electron mobility transistors, a second-channel carrier charge density function is constructed. The surface potential function is obtained by jointly approximating the first channel carrier charge density function and the second channel carrier charge density function, and the drain current function is obtained based on the surface potential function. Construct the current function at any point in the channel, and solve the current function at any point in the channel together with the drain current function to obtain the electric field function at the gate edge near the drain. Construct a source access region current expression function, and combine the source access region current expression function with the drain current function to determine the target voltage correlation function between the voltage at the gate edge of the adjacent source and the voltage at the gate edge of the adjacent drain. The target voltage correlation function and the electric field function at the gate edge of the adjacent drain are solved together to determine the voltage at the gate edge of the adjacent source and the voltage at the gate edge of the adjacent drain. The drain current of the gallium nitride high electron mobility transistor is obtained by calling the drain current function based on the solved values of the voltage at the gate edge of the adjacent source and the gate edge of the adjacent drain.
2. The method for obtaining the drain current of a gallium nitride high electron mobility transistor according to claim 1, characterized in that, The carriers in the channel of a gallium nitride high electron mobility transistor are considered as an accumulation layer and follow a Boltzmann distribution. The carrier charge density function of the first channel is obtained through the one-dimensional Poisson equation, including: Obtain the elementary charge, device temperature, preset doping concentration, and dielectric constant; The carriers in the channel of a gallium nitride high electron mobility transistor are considered as an accumulation layer and follow a Boltzmann distribution. Based on the elementary charge, device temperature, preset doping concentration, and dielectric constant, a one-dimensional Poisson equation is used to obtain the relationship function between the surface potential and the channel carrier charge density, thus obtaining the first channel carrier charge density function.
3. The method for obtaining the drain current of a gallium nitride high electron mobility transistor according to claim 1, characterized in that, Based on the static electrical characteristics of gallium nitride high electron mobility transistors, a second-channel carrier charge density function is constructed, including: The turn-off voltage, gate voltage, and barrier layer capacitance of the gallium nitride high electron mobility transistor were obtained to obtain the static electrical characteristic parameters of the gallium nitride high electron mobility transistor. Based on the static electrical characteristics of the gallium nitride high electron mobility transistor, a relationship function between surface potential and channel carrier charge density is constructed to obtain the second channel carrier charge density function.
4. The method for obtaining the drain current of a gallium nitride high electron mobility transistor according to claim 1, characterized in that, The surface potential function is obtained by jointly approximating the first channel carrier charge density function and the second channel carrier charge density function, including: The surface potential function is obtained by jointly approximating the first channel carrier charge density function and the second channel carrier charge density function using the Halley method.
5. The method for obtaining the drain current of a gallium nitride high electron mobility transistor according to claim 1, characterized in that, Obtaining the drain current function based on the surface potential function includes: The elementary charge and device temperature are obtained, and the thermal voltage is obtained based on the elementary charge and device temperature, combined with the Boltzmann constant. The overdrive voltage is obtained, and the first intermediate voltage is obtained based on the overdrive voltage, the surface potential function, and the first voltage parameter. Based on the first intermediate voltage, establish the relationship function between the voltage at the gate edge near the source, the voltage at the gate edge near the drain, and the drain current to obtain the drain current function.
6. The method for obtaining the drain current of a gallium nitride high electron mobility transistor according to claim 1, characterized in that, Construct the current function at any point in the channel, and jointly solve the current function at any point in the channel with the drain current function to obtain the electric field function at the gate edge adjacent to the drain, including: Construct the current function at any point in the channel, and solve the current function at any point in the channel together with the drain current function to obtain the potential function at any point in the channel; Differentiating the potential function at any point in the channel yields the electric field function at the gate edge near the drain.
7. The method for obtaining the drain current of a gallium nitride high electron mobility transistor according to claim 1, characterized in that, Construct a source access region current expression function, and combine the source access region current expression function with the drain current function to determine a target voltage correlation function between the voltage at the gate edge adjacent to the source and the voltage at the gate edge adjacent to the drain, including: Construct a source access region current expression function, and make the source access region current in the source access region current expression function equal to the drain current in the drain current function, so as to combine the source access region current expression function and the drain current function into a single function, and obtain the target voltage correlation function between the voltage at the gate edge of the adjacent source and the voltage at the gate edge of the adjacent drain.
8. The method for obtaining the drain current of a gallium nitride high electron mobility transistor according to claim 1, characterized in that, The target voltage correlation function and the electric field function at the gate edge of the adjacent drain are jointly solved to determine the voltage at the gate edge of the adjacent source and the voltage at the gate edge of the adjacent drain, including: According to the target voltage correlation function, the voltage at the gate edge of the source electrode in the electric field function at the gate edge of the adjacent drain electrode is completely converted into the voltage at the gate edge of the adjacent drain electrode, thus obtaining the converted electric field function at the gate edge. When the electric field at the gate edge reaches the critical electric field, the solution value of the voltage at the gate edge adjacent to the drain is obtained; Based on the solution value of the voltage at the gate edge of the adjacent drain, the solution value of the voltage at the gate edge of the adjacent source is obtained by using the target voltage correlation function.
9. The method for obtaining the drain current of a gallium nitride high electron mobility transistor according to claim 1, characterized in that, Based on the calculated voltage values at the gate edge adjacent to the source and the gate edge adjacent to the drain, the drain current of the gallium nitride high electron mobility transistor is obtained by calling the drain current function, including: The solution values of the voltage at the gate edge of the adjacent source and the voltage at the gate edge of the adjacent drain are input into the drain current function to obtain the drain current of the gallium nitride high electron mobility transistor.
10. A device for obtaining the drain current of a gallium nitride high electron mobility transistor, characterized in that, include: The first charge density function acquisition module is used to treat the carriers in the channel of the gallium nitride high electron mobility transistor as an accumulation layer and obey the Boltzmann distribution, and to obtain the first channel carrier charge density function through the one-dimensional Poisson equation. The second charge density function acquisition module is used to construct the second channel carrier charge density function based on the static electrical characteristic parameters of the gallium nitride high electron mobility transistor. The drain current function acquisition module is used to jointly approximate the first channel carrier charge density function and the second channel carrier charge density function to obtain the surface potential function, and obtain the drain current function based on the surface potential function. The electric field function acquisition module is used to construct the current function at any point in the channel and jointly solve the current function at any point in the channel with the drain current function to obtain the electric field function at the gate edge adjacent to the drain. The target voltage correlation function acquisition module is used to construct the source access region current expression function and combine the source access region current expression function with the drain current function to determine the target voltage correlation function between the voltage at the gate edge of the adjacent source and the voltage at the gate edge of the adjacent drain. The voltage solving module is used to jointly solve the target voltage correlation function and the electric field function at the gate edge of the adjacent drain to determine the solved value of the voltage at the gate edge of the adjacent source and the solved value of the voltage at the gate edge of the adjacent drain. The drain current calculation module is used to obtain the drain current of the gallium nitride high electron mobility transistor by calling the drain current function based on the calculated values of the voltage at the gate edge of the adjacent source and the voltage at the gate edge of the adjacent drain.