Online measuring system and method for drain current of floating gate MOSFET (Metal Oxide Semiconductor Field Effect Transistor)

Abstract

The invention provides a floating gate MOSFET drain current on-line measurement system and method, and mainly solves the technical problems of complex structure, high test cost, tedious operation and the like of existing test equipment. The online measurement system comprises a signal acquisition unit, a parameter configuration unit, a main control unit and a PC (Personal Computer) upper computer which are connected in sequence, the signal acquisition unit comprises a plurality of measurement channels, and each measurement channel is connected with each port of the floating gate MOSFET to be measured; the parameter configuration unit outputs excitation voltage to the to-be-measured floating gate MOSFET through the measurement channel and collects a corresponding current signal; the main control unit controls the magnitude and time of excitation voltage output by each measurement channel through the parameter configuration unit, and sends a current signal transmitted by the parameter configuration unit to the PC upper computer; and the PC upper computer sends a corresponding control instruction to the main control unit and outputs a measurement result. The device has the characteristics of low cost, portability, convenience in operation and the like.

Description

Technical Field

[0001] The invention relates to a method for measuring a drain current, and in particular to an online measurement system and method for a floating gate MOSFET drain current. Background Art

[0002] MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is a voltage-controlled power semiconductor device with the advantages of fast switching speed, good high-frequency characteristics, good thermal stability, low noise, simple driving circuit, low driving power, wide safe operating area, no secondary breakdown problem, etc. Floating Gate MOSFET (Floating Gate Metal Oxide Semiconductor Field Effect Transistor) is a widely used semiconductor device, often used in various memories, such as flash memory, hard disk, memory, etc.

[0003] The floating gate MOSFET has two gates, one of which is called the control gate, which is equivalent to the gate of an ordinary MOS device; the other is wrapped in a SiO2 dielectric layer, called a floating gate. The working principle of the floating gate MOSFET is to use the amount of charge stored on the floating gate to change the external characteristics of the MOSFET, and the transfer characteristics of the floating gate MOSFET are the curves that describe the relationship between the drain current and the gate voltage when the floating gate transistor is programmed or erased. Therefore, knowing the transfer characteristics of the floating gate MOSFET can accurately grasp the external characteristics of the MOSFET.

[0004] At present, for device developers, studying the external characteristics of a single floating-gate MOSFET requires shift testing using professional instrument testing equipment. The shift test is to load data into the register or latch inside the device for shift operations to verify whether its function is correct. This type of equipment has a complex structure, high testing cost and cumbersome operation. In addition, since this type of equipment cannot perform online testing of processes such as irradiation and temperature testing, the overall test efficiency is low and the accuracy of the test results is difficult to guarantee. Therefore, the development of a simple and portable measurement system is of great significance for practical applications. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problems of complex structure of existing test equipment, high test cost, cumbersome operation, low test efficiency, and difficulty in ensuring the accuracy of test results, and to provide a floating gate MOSFET drain current online measurement system and method.

[0006] To achieve the above objectives, the technical solutions provided by the present invention are:

[0007] A floating gate MOSFET drain current online measurement system, which is special in that:

[0008] It includes a signal acquisition unit, a parameter configuration unit, a main control unit and a PC host computer which are connected in sequence;

[0009] The signal acquisition unit includes a plurality of independent measurement channels, and each measurement channel is respectively connected to the drain port and / or the select gate port, the control gate port, and the source port of the floating gate MOSFET to be measured; each measurement channel includes a driving end and a monitoring end, which are used to realize the output and input of the signal;

[0010] The parameter configuration unit is connected to each measurement channel of the signal acquisition unit, and is used to output an excitation voltage to the floating-gate MOSFET to be measured through the measurement channel and collect a corresponding current signal;

[0011] The main control unit is used to control the magnitude and time of the output excitation voltage of each measurement channel through the parameter configuration unit, and send the current signal transmitted by the parameter configuration unit to the PC host computer;

[0012] The PC host computer is used to issue corresponding control instructions to the main control unit and output measurement results based on the received current signal; the control instructions include configuration setting instructions and measurement instructions, wherein the configuration setting instructions include direct measurement instructions, measurement instructions after programming or measurement instructions after erasing.

[0013] Furthermore, it also includes a display unit, which is connected to the PC host computer and is used to display the measurement results output by the PC host computer in real time.

[0014] Furthermore, there are four measuring channels, which are respectively connected to the drain port, the select gate port, the control gate port and the source port of the floating-gate MOSFET to be measured.

[0015] Furthermore, the parameter configuration unit is AD5522.

[0016] The present invention also provides a floating gate MOSFET drain current online measurement method, comprising the following steps:

[0017] Step 1, assembling the above floating-gate MOSFET drain current online measurement system, and connecting each measurement channel of the signal acquisition unit to each port of the floating-gate MOSFET to be measured;

[0018] Step 2: Send configuration setting instructions to the main control unit through the PC host computer, and the main control unit sets the excitation voltage output by each measurement channel through the parameter configuration unit;

[0019] Step 3, sending a measurement command to the main control unit through the PC host computer, and the main control unit controls each measurement channel to output a corresponding excitation voltage to the floating-gate MOSFET to be measured through the parameter configuration unit, and collects the corresponding current signal and transmits it to the PC host computer through the parameter configuration unit and the main control unit in sequence;

[0020] Step 4: The PC host computer processes the received current signal and outputs the measurement result, thereby realizing the online measurement of the floating gate MOSFET drain current.

[0021] Furthermore, step 2 specifically includes sending a measurement setting instruction to the main control unit through the PC host computer, and the main control unit sets the excitation voltage output by each measurement channel through the parameter configuration unit.

[0022] Furthermore, step 2 specifically includes sending a programming setting instruction to the main control unit through the PC host computer, and the main control unit sets the excitation voltage output by each measurement channel through the parameter configuration unit; then, sending a programming instruction to the main control unit through the PC host computer, and the main control unit controls each measurement channel to output a corresponding excitation voltage to the floating-gate MOSFET to be measured through the parameter configuration unit to complete programming; thereafter, sending a measurement setting instruction to the main control unit through the PC host computer, and the main control unit sets the excitation voltage of each measurement channel again through the parameter configuration unit.

[0023] Furthermore, step 2 specifically includes sending an erase setting instruction to the main control unit through the PC host computer, and the main control unit sets the excitation voltage output by each measurement channel through the parameter configuration unit; then, sending an erase instruction to the main control unit through the PC host computer, and the main control unit controls each measurement channel to output a corresponding excitation voltage to the floating-gate MOSFET to be measured through the parameter configuration unit to complete the erasure; thereafter, sending a measurement setting instruction to the main control unit through the PC host computer, and the main control unit sets the excitation voltage of each measurement channel again through the parameter configuration unit.

[0024] Furthermore, in step 4, the PC host computer outputs the measurement result in a text document format, and draws a relationship curve between the drain current and the gate voltage of the floating-gate MOSFET to be measured based on the measurement result.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The floating-gate MOSFET drain current online measurement system provided by the present invention includes a signal acquisition unit, a parameter configuration unit, a main control unit and a PC host computer, wherein the signal acquisition unit includes multiple measurement channels, and each measurement channel is respectively connected to each port of the floating-gate MOSFET to be measured; the parameter configuration unit is used to output an excitation voltage to the floating-gate MOSFET to be measured and collect the corresponding current signal; the main control unit is used to control the magnitude and time of the output excitation voltage of each measurement channel through the parameter configuration unit, and send the current signal transmitted by the parameter configuration unit to the PC host computer; the PC host computer is used to issue corresponding control instructions to the main control unit, and output the measurement result based on the received current signal. Compared with the existing shift test equipment, the present invention has a simple structure, high portability, easy operation, and can realize a variety of different measurement modes with high test accuracy.

[0027] 2. In the floating-gate MOSFET drain current online measurement system provided by the present invention, the parameter configuration unit selects AD5522, so that the overall structure integration of the measurement system is higher and the measurement accuracy is greatly improved.

[0028] 3. The floating gate MOSFET drain current online measurement system provided by the present invention is more compact and has lower testing cost than the displacement test equipment.

[0029] 4. The floating-gate MOSFET drain current online measurement method provided by the present invention is simple to operate and can assist operators in obtaining more realistic test results through online testing, thereby providing accurate data support for the performance analysis of the floating-gate MOSFET. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of an embodiment of a floating-gate MOSFET drain current online measurement system of the present invention;

[0031] Figure 2 The present invention is a schematic flow chart of an embodiment of a floating-gate MOSFET drain current online measurement method. DETAILED DESCRIPTION

[0032] In order to make the purpose, advantages and features of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0033] like Figure 1 As shown, this embodiment provides a floating-gate MOSFET drain current online measurement system, including a signal acquisition unit, a parameter configuration unit, a main control unit and a PC host computer connected in sequence.

[0034] The signal acquisition unit includes multiple independent measurement channels, and each measurement channel is connected to each port of the floating-gate MOSFET to be tested. In this embodiment, there are 4 measurement channels, each of which is connected to the gate, drain, source and body of the floating-gate MOSFET to be tested using an SMA cable, which is used for connecting the parameter configuration unit to the floating-gate MOSFET to be tested.

[0035] The parameter configuration unit is connected to each measurement channel of the signal acquisition unit, and is used to output the excitation voltage to the floating-gate MOSFET to be measured and collect the corresponding current signal through the measurement channel. The parameter configuration unit uses AD5522, which is a highly integrated four-channel per-pin parameter measurement unit (PPMU) suitable for semiconductor automatic test equipment. It provides a variety of programmable modes, can drive the pin voltage and measure the corresponding current (FVMI), and also supports other combinations, including driving high resistance and measuring high resistance. PPMU can drive or measure a voltage range within 22.5V. In addition, the internal amplifier can be used to drive or measure currents up to ±80mA per channel, and an external amplifier can be used to achieve a higher current range. All DAC level settings required for each PPMU channel are already integrated on the driver chip.

[0036] Specifically, the parameter configuration unit consists of a driver amplifier, a measurement current amplifier, a system driver and a detection switch, etc., wherein the driver amplifier is used to drive the analog output and output a programmable current or voltage to the floating-gate MOSFET to be tested. The thin-film resistors integrated inside the parameter configuration unit provide the following current ranges: ±5μA (200kΩ), ±20μA (50kΩ), ±200μA (5kΩ) and ±2mA (500Ω). By connecting an external detection resistor, each channel can support a current range of up to ±80mA. The driver amplifier input (FIN) DAC level contains independent gain and offset control registers to digitally adjust the gain and offset.

[0037] The measurement current amplifier has two gain settings, 5 and 10, which achieve the specified current range by increasing or decreasing the voltage swing. When the reference voltage is 5V, a gain setting of 10 is used, and when the reference voltage is 2.5V, a gain setting of 5 is used.

[0038] Each measurement channel has sense switches to connect the drive and sense lines to the central PMU (central processing unit) for calibration.

[0039] The main control unit is an MCU main control unit, which is used to control the size and time of the output excitation voltage of each measurement channel through the parameter configuration unit, and send the current signal transmitted by the parameter configuration unit to the PC host computer. The MCU main control unit is mainly used to perform logical control on the parameter configuration unit, which designs the control logic of the parameter control and mode switching program. The main control unit of this embodiment controls the time of the output excitation voltage of a single measurement channel and forms a voltage pulse to achieve the current measurement and "programming / erasing" functions of the floating gate MOSFET to be measured, and then completes data upload through the serial port, and outputs the measurement data curve and measurement results through the host computer.

[0040] The PC host computer is used to issue corresponding control instructions to the main control unit and output the measurement results based on the received current signal, so as to draw the relationship curve between the drain current and the gate voltage. The PC host computer uses the Qt Creator platform to write the control program code, and realizes the logic control of the main control unit and the parameter adjustment of the parameter measurement unit by adjusting the code content. The control program of the PC host computer allows three modes: mode 1 is the measurement mode (Read), mode 2 is the programming mode (Program), and mode 3 is the erase mode (Erase).

[0041] This embodiment also includes a display unit, which is connected to the PC host computer and is used to display the measurement results output by the PC host computer in real time.

[0042] This embodiment can measure the drain current of the floating gate MOSFET and can realize the function of "programming / erasing" the floating gate MOSFET, thereby realizing the drawing of the transfer characteristic curve, so that the operator can intuitively understand the characteristics of the floating gate MOSFET to be tested. It has the advantages of easy operation, low cost, miniaturization, and high portability.

[0043] In addition, this embodiment also provides an online floating-gate MOSFET drain current measurement method, which can realize direct measurement, measurement after programming and measurement after erasing of the floating-gate MOSFET to be measured, thereby forming three measurement modes.

[0044] 1. When the direct measurement mode is adopted, the following steps are specifically included:

[0045] Step 1: Assemble the floating-gate MOSFET drain current online measurement system described in this embodiment, and connect each measurement channel of the signal acquisition unit to each port of the floating-gate MOSFET to be measured.

[0046] The signal acquisition unit of this embodiment includes 4 SMU (Source Measure Unit) channels: SMU1, SMU2, SMU3 and SMU4. Each SMU channel has a drive and monitoring circuit to realize signal output and input. Its switch is controlled by the main control unit, and multiple channels can simultaneously input or output signals. The connection method of the SMU channel and the floating gate MOSFET port to be tested is: SMU1 is connected to the drain (D) of the floating gate MOSFET, SMU2 is connected to the select gate (SG) of the floating gate MOSFET, SMU3 is connected to the control gate (CG) of the floating gate MOSFET, SMU4 is connected to the source (S) of the floating gate MOSFET, and the body (B) of the floating gate MOSFET is grounded (GND). The connection order of the above SMU channels and device ports is not unique, and only one of the connection methods is used here.

[0047] Step 2: Send the measurement setting command to the main control unit through the PC host computer, and the main control unit sets the excitation voltage output by each measurement channel through the parameter configuration unit. The parameter configuration unit outputs or inputs a voltage within the range of ±11.25V and a current within the range of ±80mA through the four SMU channels of the signal acquisition channel of the main control unit, and outputs the excitation voltage through a certain channel under the program control of the PC host computer and the control of the main control unit, thereby measuring the current of a certain channel.

[0048] In this embodiment, in direct measurement mode, SMU1 outputs any voltage value in the range of -1V to -0.1V, SMU2 outputs any voltage value in the range of -5V to -1V, SMU3 outputs a voltage scan from -7V to 7V, and SMU4 outputs 0V.

[0049] Step 3: Send the measurement command to the main control unit through the PC host computer. The main control unit controls each measurement channel to output the corresponding excitation voltage to the floating-gate MOSFET to be measured through the parameter configuration unit, and collects the corresponding current signal and transmits it to the PC host computer through the parameter configuration unit and the main control unit in turn. In the measurement mode, the current value measured by SMU1 is returned, that is, the drain current of the floating-gate MOSFET.

[0050] Step 4: The PC host computer processes the received current signal and outputs the measurement result, thereby realizing the online measurement of the floating gate MOSFET drain current.

[0051] The PC host computer of this embodiment outputs the measurement result in a text document (.txt) format, and draws a relationship curve (ID-VG curve) between the drain current and the gate voltage of the floating-gate MOSFET to be measured based on the measurement result.

[0052] 2. When it is the post-programming measurement mode, the following steps are specifically included:

[0053] Step 1: Assemble the floating-gate MOSFET drain current online measurement system described in this embodiment, and connect each measurement channel of the signal acquisition unit to each port of the floating-gate MOSFET to be measured. The specific connection method is the same as step 1 of the direct measurement mode.

[0054] Step 2: Send programming setting instructions to the main control unit through the PC host computer, and the main control unit sets the excitation voltage output by each measurement channel through the parameter configuration unit. In this embodiment, SMU1 outputs any voltage value in the range of -8V to -4V, SMU2 outputs any voltage value in the range of -10V to -3V, SMU3 outputs any voltage value in the range of 5V to 10V, and SMU4 outputs a voltage value of -0.9V.

[0055] Next, the programming instructions are sent to the main control unit through the PC host computer. The main control unit controls each measurement channel to output the corresponding excitation voltage to the floating-gate MOSFET to be tested through the parameter configuration unit. At this time, the PC host computer displays "Programming completed!".

[0056] Afterwards, the measurement setting command is sent to the main control unit through the PC host computer, and the main control unit re-sets the excitation voltage output by each measurement channel through the parameter configuration unit. Specifically, SMU1 outputs any voltage value in the range of -1V to -0.1V, SMU2 outputs any voltage value in the range of -5V to -1V, SMU3 outputs a voltage scan from -7V to 7V, and SMU4 outputs 0V.

[0057] Step 3: Send measurement instructions to the main control unit through the PC host computer. The main control unit controls each measurement channel to output the corresponding excitation voltage to the floating-gate MOSFET to be measured through the parameter configuration unit, and collects the corresponding current signal and transmits it to the PC host computer through the parameter configuration unit and the main control unit in turn.

[0058] Step 4: The PC host computer processes the received current signal and outputs the measurement result, thereby realizing the online measurement of the floating gate MOSFET drain current.

[0059] 3. When it is the post-erase measurement mode, the following steps are specifically included:

[0060] Step 1: Assemble the floating-gate MOSFET drain current online measurement system described in this embodiment, and connect each measurement channel of the signal acquisition unit to each port of the floating-gate MOSFET to be measured. The specific connection method is the same as step 1 of the direct measurement mode.

[0061] Step 2: Send an erase setting command to the main control unit through the PC host computer, and the main control unit sets the excitation voltage output by each measurement channel through the parameter configuration unit. In this embodiment, SMU1 does not output a value, SMU2 outputs any voltage value in the range of 7V to 10V, SMU3 outputs any voltage value in the range of -10V to -5V, and the voltage value output by SMU4 is 0V.

[0062] Next, the erase command is sent to the main control unit through the PC host computer, and the main control unit controls each measurement channel to output the corresponding excitation voltage to the floating-gate MOSFET to be tested through the parameter configuration unit. At this time, the PC host computer displays "Erase Completed!".

[0063] Afterwards, the measurement setting command is sent to the main control unit through the PC host computer, and the main control unit re-sets the excitation voltage of each measurement channel through the parameter configuration unit. Specifically, SMU1 outputs any voltage value in the range of -1V to -0.1V, SMU2 outputs any voltage value in the range of -5V to -1V, SMU3 outputs a voltage scan from -7V to 7V, and SMU4 outputs 0V.

[0064] Step 3: Send measurement instructions to the main control unit through the PC host computer. The main control unit controls each measurement channel to output the corresponding excitation voltage to the floating-gate MOSFET to be measured through the parameter configuration unit, and collects the corresponding current signal and transmits it to the PC host computer through the parameter configuration unit and the main control unit in turn.

[0065] Step 4: The PC host computer processes the received current signal and outputs the measurement result, thereby realizing the online measurement of the floating gate MOSFET drain current.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A floating gate MOSFET drain current online measurement system, characterized in that: It includes a signal acquisition unit, a parameter configuration unit, a main control unit and a PC host computer which are connected in sequence; The signal acquisition unit includes a plurality of independent measurement channels, and each measurement channel is respectively connected to the drain port and / or the select gate port, the control gate port, and the source port of the floating gate MOSFET to be measured; each measurement channel includes a driving end and a monitoring end, which are used to realize the output and input of the signal; The parameter configuration unit is connected to each measurement channel of the signal acquisition unit, and is used to output an excitation voltage to the floating-gate MOSFET to be measured through the measurement channel and collect a corresponding current signal; The main control unit is used to control the magnitude and time of the output excitation voltage of each measurement channel through the parameter configuration unit, and send the current signal transmitted by the parameter configuration unit to the PC host computer; The PC host computer is used to issue corresponding control instructions to the main control unit and output measurement results based on the received current signal; the control instructions include configuration setting instructions and measurement instructions, wherein the configuration setting instructions include direct measurement instructions, measurement instructions after programming or measurement instructions after erasing.

2. The floating gate MOSFET drain current online measurement system according to claim 1, characterized in that: The device also includes a display unit, which is connected to the PC host computer and is used to display the measurement results output by the PC host computer in real time.

3. The floating gate MOSFET drain current online measurement system according to claim 2, characterized in that: There are four measuring channels, which are respectively connected to the drain port, the select gate port, the control gate port and the source port of the floating gate MOSFET to be measured.

4. The floating gate MOSFET drain current online measurement system according to claim 1, characterized in that: The parameter configuration unit is AD5522.

5. A floating gate MOSFET drain current online measurement method, characterized in that: The following steps are involved: Step 1, assembling the floating-gate MOSFET drain current online measurement system according to any one of claims 1 to 4, and connecting each measurement channel of the signal acquisition unit to each port of the floating-gate MOSFET to be measured; Step 2: Send configuration setting instructions to the main control unit through the PC host computer, and the main control unit sets the excitation voltage output by each measurement channel through the parameter configuration unit; Step 3, sending a measurement command to the main control unit through the PC host computer, and the main control unit controls each measurement channel to output a corresponding excitation voltage to the floating-gate MOSFET to be measured through the parameter configuration unit, and collects the corresponding current signal and transmits it to the PC host computer through the parameter configuration unit and the main control unit in sequence; Step 4: The PC host computer processes the received current signal and outputs the measurement result, thereby realizing the online measurement of the floating gate MOSFET drain current.

6. The floating gate MOSFET drain current online measurement method according to claim 5, characterized in that: Step 2 specifically includes sending a measurement setting instruction to the main control unit through the PC host computer, and the main control unit sets the excitation voltage output by each measurement channel through the parameter configuration unit.

7. The method for online measurement of the drain current of a floating gate MOSFET according to claim 5, characterized in that: Step 2 specifically includes sending a programming setting instruction to the main control unit through the PC host computer, and the main control unit sets the excitation voltage output by each measurement channel through the parameter configuration unit; then, sending a programming instruction to the main control unit through the PC host computer, and the main control unit controls each measurement channel to output the corresponding excitation voltage to the floating gate MOSFET to be measured through the parameter configuration unit, thereby completing the programming; Afterwards, the PC host sends a measurement setting instruction to the main control unit, and the main control unit resets the excitation voltage of each measurement channel through the parameter configuration unit.

8. The floating gate MOSFET drain current online measurement method according to claim 5, characterized in that: Step 2 specifically includes sending an erase setting instruction to the main control unit through the PC host computer, and the main control unit sets the excitation voltage output by each measurement channel through the parameter configuration unit; then, sending an erase instruction to the main control unit through the PC host computer, and the main control unit controls each measurement channel to output the corresponding excitation voltage to the floating gate MOSFET to be measured through the parameter configuration unit to complete the erase; Afterwards, the PC host computer sends a measurement setting instruction to the main control unit, and the main control unit resets the excitation voltage of each measurement channel through the parameter configuration unit.

9. The floating gate MOSFET drain current online measurement method according to any one of claims 5 to 8, characterized in that: In step 4, the PC host computer outputs the measurement result in the format of a text document, and draws a relationship curve between the drain current and the gate voltage of the floating-gate MOSFET to be measured based on the measurement result.

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