Method for establishing simulation model of output characteristics of organic semiconductor transistor

Abstract

The invention discloses a method for establishing an output characteristic simulation model of an organic semiconductor transistor, and relates to the field of semiconductor devices, in particular to the method for establishing the output characteristic simulation model of the organic semiconductor transistor. The objective of the invention is to solve the problems of low accuracy of a constructed simulation model and low accuracy of an obtained current-voltage output characteristic curve caused by limited consideration factors of an existing organic semiconductor transistor output characteristic simulation model. The method comprises the following steps of: 1, calculating a mobility empirical parameter gamma changing along with a gate-source voltage VGS; step 2, calculating a carrier mobility characteristic parameter VAA changing along with the gate-source voltage VGS; 3, calculating a saturation modulation parameter alpha s; 4, calculating a sharpness parameter m of the inflection point region; 5, calculating the channel conductivity gch of the transistor; step 6, calculating the carrier mobility mu; and step 7, constructing a current-voltage output characteristic curve model based on gamma, VAA, alpha s, m, gch and mu.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor devices, in particular to the field of organic semiconductor transistor device model simulation, and specifically relates to a method for establishing an organic semiconductor transistor output characteristic simulation model. Background Art

[0002] As a new type of semiconductor device, the organic field-effect transistor (OFET) has a very broad development prospect and has a very promising development prospect in the fields of biomedicine, batch printing manufacturing, etc. However, compared with traditional organic semiconductor devices, the research on OFET is still in its infancy. Its diverse composition and corresponding complex properties have greatly hindered the development of device modeling.

[0003] Currently, most of the models used for OFET simulation are based on adding parameters on the basis of imitating traditional semiconductor models. For example, the basic parameters that affect the characteristics of OFET, such as threshold current, subthreshold current, grain boundary barrier, channel resistance, carrier concentration, and trap state density. There are also teams using new functions or new algorithms for simulation.

[0004] The model of the Ognian Marinov team focuses on the non-linear part that often appears in actual experimental results. This model considers the non-linear region change that occurs when the field-effect transistor transitions from the linear region to the saturation region and the exponential relationship between the subthreshold current and the gate voltage. By differentiating the gate, drain, and source voltages instead of the general gate-source voltage and drain-source voltage, an effective gate overdrive voltage equation is introduced, and at the same time, the transition region characteristics from the linear region to the saturation region and the transition region characteristics near the threshold are realized. However, due to the limitations of the model itself, the non-linear region in the simulation process is too long, and there is an obvious deviation from the experimental data, especially the current simulation near the threshold voltage.

[0005] The model of the M.Estrada team shows the changes of OFET under different external conditions. Compared with the model of the Marinovt team, the model of the Estrada team shows greater flexibility in parameters, and is combined into an expression through a series of independently defined equations. This means that for different devices, we can easily change the parameters in the model to fix different characteristics. This model emphasizes the power-law relationship between the mobility and the gate overdrive voltage based on UMEM (Unified Model and Parameter Extraction Method). In addition, in addition to the threshold voltage, they also considered the influence of the turn-on voltage on the OFET device, but they did not really complete the modeling of this influence. In reality, there is a relatively small current change in the subthreshold region of the OFET, which is caused by subthreshold leakage. And even when the voltage does not reach the threshold voltage, the actual OFET can start working, but the simulation results of the Estrada team show that the OFET can only start at the threshold voltage.

[0006] The simulation model of the LingLi team takes into account the potential barrier between particles and gives an expression for the mobility related to the gate voltage. This model uses several empirical parameters, so the simulation results in the region above the threshold voltage are significantly improved. They obtained the change of the barrier height with respect to the gate voltage through a series of independent equations related to lattice characteristics and barriers, and pointed out that the barrier height will decrease as the gate voltage increases. However, due to the choice of the exp function in their model, when the voltage gradually approaches the threshold voltage, their simulation results approach infinitesimal and completely lose the characteristics of the subthreshold part. Summary of the Invention

[0007] The purpose of the present invention is to solve the problem that the existing simulation model of the output characteristics of organic semiconductor transistors has limited consideration factors, resulting in low accuracy of the constructed simulation model and low accuracy of the obtained current-voltage output characteristic curve, and to propose a method for establishing a simulation model of the output characteristics of organic semiconductor transistors.

[0008] The specific process of a method for establishing a simulation model of the output characteristics of organic semiconductor transistors is as follows:

[0009] Step 1, calculate the mobility empirical parameter γ that varies with the gate-source voltage V GS ;

[0010] Step 2, calculate the carrier mobility characteristic parameter V GS that varies with the gate-source voltage V AA ;

[0011] Step 3, calculate the saturation modulation parameter α s ;

[0012] Step 4, calculate the sharpness parameter m in the inflection point region;

[0013] Step 5, calculate the transistor channel conductivity g ch ;

[0014] Step 6, calculate the carrier mobility μ;

[0015] Step 7, based on the mobility empirical parameter γ that varies with the gate-source voltage V GS , the carrier mobility characteristic parameter V GS that varies with the gate-source voltage V AA , the saturation modulation parameter α s , the sharpness parameter m in the inflection point region, the transistor channel conductivity g ch , and the carrier mobility μ, construct a current-voltage output characteristic curve model.

[0016] Preferably, in Step 1, when calculating the mobility empirical parameter γ that varies with the gate-source voltage V GSThe variable mobility empirical parameter γ; the expression is:

[0017]

[0018] Wherein,

[0019] H(V GS ) represents a function related to the gate-source voltage;

[0020] V GS represents the gate-source voltage;

[0021] I DS (x) represents the functional relationship between the gate-source voltage and the drain-source current;

[0022] I DS (V GS ) represents the drain-source current at the gate-source voltage V GS ;

[0023] γ represents a carrier mobility power-law parameter that varies with the gate-source voltage V GS ;

[0024] V T represents the threshold voltage.

[0025] Preferably, in the second step, the carrier mobility characteristic parameter V GS that varies with the gate-source voltage V AA is calculated; the expression is:

[0026]

[0027] Wherein,

[0028] W represents the width of the transistor channel, and L represents the length of the transistor channel;

[0029] S 1 represents the slope between;

[0030] represents the relationship curve of the 1 / (1 + γ) power of the drain-source current I DS versus the gate-source voltage V GS ;

[0031] C represents the transistor capacitance; μ represents the carrier mobility;

[0032] V DS represents the drain-source voltage.

[0033] Preferably, in the third step, the saturation modulation parameter α s is calculated, and the expression is:

[0034]

[0035] Among them,

[0036] S s represents the slope between

[0037] represents the 1 / (2 + γ)-th power of the drain-source current I DS and the relationship curve with (V GS - V T ).

[0038] Preferably, in the fourth step, the sharpness parameter m of the inflection point region is calculated, and the expression is:

[0039]

[0040] Among them,

[0041] I DS (V DS ) represents the drain-source current varying with V DS ;

[0042] V DS represents the drain-source voltage;

[0043] I DS represents the drain-source current.

[0044] Preferably, in the fifth step, the transistor channel conductivity g ch is calculated, and the expression is:

[0045]

[0046] Among them,

[0047] R s represents the source resistance; R d represents the drain resistance;

[0048] q represents the carrier charge; η 0 represents the zero-bias subthreshold slope;

[0049] C ox represents the capacitance per unit area;

[0050] η represents the subthreshold slope, k represents the Boltzmann constant, and T represents the temperature;

[0051] μ represents the carrier mobility;

[0052] g ch represents the transistor channel conductivity;

[0053] V on represents the switching voltage;

[0054] Preferably, in step six, the carrier mobility μ is calculated, and the expression is:

[0055]

[0056] where μ represents the carrier mobility;

[0057] W represents the channel width;

[0058] C represents the transistor capacitance.

[0059] Preferably, in step seven, based on the mobility empirical parameter γ that varies with the gate-source voltage V GS the carrier mobility characteristic parameter V that varies with the gate-source voltage V GS the saturation modulation parameter α AA the sharpness parameter m in the inflection point region, the transistor channel conductivity g s and the carrier mobility μ, a current-voltage output characteristic curve model is constructed; it is expressed as: ch The beneficial effects of the present invention are as follows:

[0060]

[0061] The present invention discloses a method for establishing an output characteristic simulation model of an organic semiconductor transistor, which mainly solves the influence of contact resistance on the output characteristics of the organic semiconductor transistor. It mainly includes the following steps:

[0062] 1), Obtaining test parameters by controlling voltage changes, including the mobility empirical parameter γ that varies with the gate-source voltage V

[0063] GS the carrier mobility characteristic parameter V that varies with the gate-source voltage V GS the saturation modulation parameter α AA the sharpness parameter m in the inflection point region, the transistor channel conductivity g s ch and the carrier mobility μ, which improves the accuracy of the constructed simulation model; ch 2), Obtaining necessary parameters according to the current-voltage output characteristic model establishment method;

[0064] 3), Substituting the parameters into the current-voltage output characteristic curve model function to complete the simulation model, which improves the accuracy of the current-voltage output characteristic curve;

[0065] The technical problem to be solved by the present invention is to establish a more perfect output characteristic model of an organic semiconductor transistor (OFET), and to propose an accurate parameter extraction method by focusing on the influence of contact resistance on the output characteristics, so as to achieve the purpose of making the output characteristics more accurate.

[0066] ​

[0067] An accurate simulation model for describing the output characteristics is obtained by using a method for extracting the current-voltage characteristic model parameters of a sample device and an organic semiconductor.

[0068] The present invention is applicable to the field of development and design of organic semiconductor transistors. By cooperating with corresponding transistor samples, more accurate simulation analysis results can be obtained for subsequent research and development. It is particularly applicable to the analysis of novel organic semiconductor transistors, which can reduce the complexity of transistor development and avoid waste of raw materials during the design and development process. In addition, the present invention can also be integrated as basic data in the databases of other organic semiconductor transistor development tools and used as basic parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 A flowchart is established for the simulation method of the output characteristics of the organic semiconductor transistor described in the present invention;

[0070] Figure 2a A comparison diagram of the simulation results of the output characteristics of the organic semiconductor transistor described in the present invention and the simulation results of several existing models mentioned;

[0071] Figure 2b For Figure 2a A comparison diagram of the results of smaller numbers expressed on a logarithmic coordinate axis in

[0072] V GS (V) represents the gate-source voltage, with the unit of V; I DS (A) represents the drain-source current, with the unit of A;

[0073] Figure 3 A schematic diagram of the curve of the resistance of the organic semiconductor transistor described in the present invention changing with voltage, where R (Ω) represents the resistance and the unit is Ω;

[0074] Figure 4 A schematic diagram of the design of the zinc oxide tin transistor used in the implementation example described in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0075] DETAILED DESCRIPTION OF THE EMBODIMENT 1: The specific process of a method for establishing a simulation model of the output characteristics of an organic semiconductor transistor in this embodiment is as follows:

[0076] Step 1: Calculate the mobility empirical parameter γ that changes with the gate-source voltage V GS ;

[0077] Step 2: Calculate the carrier mobility characteristic parameter V GS that changes with the gate-source voltage V AA ;

[0078] Step 3: Calculate the saturation modulation parameter α s ;

[0079] Step 4: Calculate the sharpness parameter m of the inflection point region;

[0080] Step 5: Calculate the transistor channel conductivity g ch ;

[0081] Step 6: Calculate the carrier mobility μ;

[0082] Step 7: Based on the mobility empirical parameter γ that varies with the gate-source voltage V GS , the carrier mobility characteristic parameter V GS that varies with the gate-source voltage V AA , the saturation modulation parameter α s , the sharpness parameter m of the inflection point region, the transistor channel conductivity g ch , and the carrier mobility μ, construct a current-voltage output characteristic curve model.

[0083] Specific Embodiment 2: The difference between this embodiment and Specific Embodiment 1 is that in Step 1, calculate the mobility empirical parameter γ that varies with the gate-source voltage V GS ; the expression is:

[0084]

[0085] Where

[0086] H(V GS ) represents a gate-source voltage related function;

[0087] V GS represents the gate-source voltage;

[0088] I DS (x) represents the functional relationship between the gate-source voltage and the drain-source current;

[0089] I DS (V GS ) represents the drain-source current at the gate-source voltage V GS ;

[0090] γ represents a carrier mobility power-law parameter that varies with the gate-source voltage V GS ;

[0091] V T represents the threshold voltage.

[0092] Other steps and parameters are the same as those in Specific Embodiment 1.

[0093] Specific Embodiment 3: The difference between this embodiment and Specific Embodiment 1 or 2 is that in Step 2, calculate the carrier mobility characteristic parameter V GS that varies with the gate-source voltage V AA; The expression is:

[0094]

[0095] Wherein,

[0096] W represents the width of the transistor channel, and L represents the length of the transistor channel;

[0097] S 1 represents the slope between;

[0098] represents the relationship curve of the 1 / (1 + γ) power of the drain-source current I DS and the gate-source voltage V GS ;

[0099] C represents the transistor capacitance; μ represents the carrier mobility;

[0100] V DS represents the drain-source voltage.

[0101] Other steps and parameters are the same as those in the first or second specific implementation manner.

[0102] Specific implementation manner four: The difference between this implementation manner and one of the first to third specific implementation manners is that in step three, the saturation modulation parameter α s is calculated, and the expression is:

[0103]

[0104] Wherein,

[0105] S s represents the slope between;

[0106] represents the relationship curve of the 1 / (2 + γ) power of the drain-source current I DS and (V GS - V T );

[0107] Other steps and parameters are the same as those in one of the first to third specific implementation manners.

[0108] Specific implementation manner five: The difference between this implementation manner and one of the first to fourth specific implementation manners is that in step four, the sharpness parameter m of the inflection point region is calculated, and the expression is:

[0109]

[0110] Wherein,

[0111] I DS (V DS ) represents as VDS Changing drain-source current;

[0112] V DS represents the drain-source voltage;

[0113] I DS represents the drain-source current.

[0114] Other steps and parameters are the same as those in any one of the first to fourth specific embodiments.

[0115] Specific embodiment six: The difference between this embodiment and any one of the first to fifth specific embodiments is that in step five, the conductivity g of the transistor channel is calculated ch , and the expression is:

[0116]

[0117] where,

[0118] R s represents the source resistance; R d represents the drain resistance;

[0119] q represents the carrier charge; η 0 represents the zero-bias subthreshold slope;

[0120] C ox represents the capacitance per unit area;

[0121] η represents the subthreshold slope, k represents the Boltzmann constant, and T represents the temperature;

[0122] μ represents the carrier mobility;

[0123] g ch represents the conductivity of the transistor channel;

[0124] V on represents the switching voltage;

[0125] Other steps and parameters are the same as those in any one of the first to fifth specific embodiments.

[0126] Specific embodiment seven: The difference between this embodiment and any one of the first to sixth specific embodiments is that in step six, the carrier mobility μ is calculated, and the expression is:

[0127]

[0128] where,

[0129] μ represents the carrier mobility;

[0130] W represents the channel width;

[0131] C represents the transistor capacitance.

[0132] Other steps and parameters are the same as those in any one of the first to sixth specific embodiments.

[0133] Specific embodiment eight: The difference between this embodiment and any one of the first to seventh specific embodiments is that in step seven, based on the mobility empirical parameter γ that varies with the gate-source voltage V GS the carrier mobility characteristic parameter V GS that varies with the gate-source voltage V AA , the saturation modulation parameter α s , the sharpness parameter m of the inflection point region, the transistor channel conductivity g ch , and the carrier mobility μ, a current-voltage output characteristic curve model is constructed; expressed as:

[0134]

[0135] Other steps and parameters are the same as those in any one of the first to seventh specific embodiments.

[0136] The transistor terminal voltages V GS , V DS , the current I DS and the threshold voltage V T are determined by the parameters given in the experiment. The extracted parameters are obtained by fitting and simulating the experimental data, and the influence of the process will be considered in this process and no further processing is required.

[0137] Design a sample device as shown in Figure 4 , including four pairs of transistors on the same layout, to achieve the purpose of simultaneously testing four transistors with the same channel width and different channel lengths.

[0138] The following examples are used to verify the beneficial effects of the present invention:

[0139] Example 1:

[0140] The steps for establishing a model of an organic semiconductor transistor output characteristic fitting method are as follows:

[0141] In the experiment, zinc oxide tin transistors are selected to design an equal-width-differential length channel transistor module for convenient data acquisition.

[0142] Channel length Channel width <![CDATA[V DS > <![CDATA[V T > 50, 80, 100, 120, 150 μm 1 mm 40V 8.93V

[0143] Calculate the necessary parameters according to the following steps

[0144] 1)

[0145] Among them,

[0146] H(V GS ) represents the gate-source voltage related function;

[0147] V GS represents the gate-source voltage;

[0148] I DS (x) represents the functional relationship between the gate-source voltage and the drain-source current;

[0149] I DS (V GS ) represents the drain-source current at the gate-source voltage V GS ;

[0150] γ represents a carrier mobility power-law parameter that varies with the gate-source voltage V GS ;

[0151] V T represents the threshold voltage;

[0152] Calculate γ according to the above formula;

[0153] 2),

[0154] where,

[0155] W represents the width of the transistor channel, and L represents the length of the transistor channel;

[0156] S 1 represents the slope between;

[0157] represents the relationship curve between the 1 / (1 + γ) power of the drain-source current I DS and the gate-source voltage V GS ;

[0158] C represents the transistor capacitance; μ represents the carrier mobility;

[0159] V DS represents the drain-source voltage;

[0160] Calculate V AA ;

[0161] 3),

[0162] where,

[0163] S s represents the slope between;

[0164] represents the relationship curve between the 1 / (2 + γ) power of the drain-source current I DS and (V GS -V T );

[0165] Calculate α according to the above formula s ;

[0166] 4),

[0167] wherein,

[0168] I DS (V DS ) represents the drain-source current varying with V DS ;

[0169] V DS represents the drain-source voltage;

[0170] I DS represents the drain-source current;

[0171] Calculate the parameter m according to the above formula;

[0172] 5),

[0173] wherein,

[0174] R s represents the source resistance;

[0175] R d represents the drain resistance;

[0176] q represents the carrier charge;

[0177] η 0 represents the zero-bias subthreshold slope;

[0178] C ox represents the capacitance per unit area;

[0179] η represents the subthreshold slope, k represents the Boltzmann constant, and T represents the temperature;

[0180] μ represents the carrier mobility;

[0181] g ch represents the transistor channel conductivity;

[0182] V on represents the switching voltage;

[0183] Calculate g according to the above formula ch ;

[0184] 6),

[0185] wherein,

[0186] μ represents the carrier mobility;

[0187] W represents the channel width;

[0188] C represents the transistor capacitance;

[0189] Calculate μ according to the above formula;

[0190] 7), Substitute the parameters into the final equation and perform simulation

[0191]

[0192] The present invention may also have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention. However, these corresponding changes and deformations should fall within the protection scope of the appended claims of the present invention.

Claims

1. A method for establishing an output characteristic simulation model of an organic semiconductor transistor, characterized in that: The specific process of the method is: Step 1: Calculate the gate-source voltage V GS Changing liquidity experience parameter γ; Step 2: Calculate the gate-source voltage V GS The characteristic parameter V of the carrier mobility changes AA ; Step 3: Calculate the saturation modulation parameter α s ; Step 4, calculating the sharpness parameter m of the inflection point area; Step 5: Calculate the transistor channel conductivity g ch ; Step 6: Calculate the carrier mobility μ; Step 7: Based on the gate-source voltage V GS The variable mobility empirical parameter γ varies with the gate-source voltage V GS The characteristic parameter V of the carrier mobility changes AA , saturation modulation parameter α s , the sharpness parameter m of the inflection point region, and the transistor channel conductivity g ch , carrier mobility μ, and construct a current-voltage output characteristic curve model.

2. The method for establishing an output characteristic simulation model of an organic semiconductor transistor according to claim 1, characterized in that: In step 1, the gate-source voltage V is calculated GS The variable liquidity empirical parameter γ is expressed as: in, H(V GS ) represents the gate-source voltage correlation function; V GS represents the gate-source voltage; I DS (x) represents the functional relationship between gate-source voltage and drain-source current; I DS (V GS ) represents the gate-source voltage V GS Drain-source current under γ represents a gate-source voltage V GS Varying carrier mobility power rate parameter; V T Represents the threshold voltage.

3. The method for establishing an output characteristic simulation model of an organic semiconductor transistor according to claim 2, characterized in that: In step 2, the gate-source voltage V is calculated GS The characteristic parameter V of the carrier mobility changes AA ; The expression is: in, W represents the width of the transistor channel, and L represents the length of the transistor channel; S1 means The slope between Represents the drain-source current I DS 1 / (1+γ)th power and gate-source voltage V GS The relationship curve of C represents the transistor capacitance; μ represents the carrier mobility; V DS Represents the drain-source voltage.

4. The method for establishing an output characteristic simulation model of an organic semiconductor transistor according to claim 3, characterized in that: In step 3, the saturation modulation parameter α is calculated. s , the expression is: in, S s express The slope between Represents the drain-source current I DS 1 / (2+γ) power and (V GS -V T ) relationship curve.

5. The method for establishing an output characteristic simulation model of an organic semiconductor transistor according to claim 4, characterized in that: In step 4, the sharpness parameter m of the inflection point area is calculated, and the expression is: in, I DS (V DS ) indicates that V DS Varying drain-source current; V DS represents the drain-source voltage; I DS Represents the drain-source current.

6. The method for establishing an output characteristic simulation model of an organic semiconductor transistor according to claim 5, characterized in that: In step 5, the transistor channel conductivity g is calculated. ch , the expression is: in, R s Represents source resistance; R d represents the drain resistance; q represents the carrier charge; η0 represents the zero-bias subthreshold slope; C ox Represents capacitance per unit area; η represents the subthreshold slope, k represents the Boltzmann constant, and T represents the temperature; μ represents carrier mobility; g ch represents the transistor channel conductivity; V on Indicates the switching voltage.

7. The method for establishing an output characteristic simulation model of an organic semiconductor transistor according to claim 6, characterized in that: In step 6, the carrier mobility μ is calculated, and the expression is: in, μ represents carrier mobility; W represents the channel width; C represents the transistor capacitance.

8. The method for establishing an output characteristic simulation model of an organic semiconductor transistor according to claim 7, characterized in that: In step 7, based on the gate-source voltage V GS The variable mobility empirical parameter γ varies with the gate-source voltage V GS The characteristic parameter V of the carrier mobility changes AA , saturation modulation parameter α s , the sharpness parameter m of the inflection point region, and the transistor channel conductivity g ch , carrier mobility μ, construct the current-voltage output characteristic curve model; expressed as:

Images