Used to explain this book.
Guangzhou kunde technology co., ltd
1, overview
KDY- 1 Four-probe Resistivity/Square Resistance Tester (hereinafter referred to as Resistivity Tester) is used to measure the resistivity of semiconductor materials (mainly silicon single crystal, germanium single crystal and silicon wafer), as well as the resistance of diffusion layer, epitaxial layer, ITO conductive film and conductive rubber square. It is mainly composed of an electrical measuring part (referred to as the host), a test bench and four probes.
The characteristic of this instrument is that the main machine is equipped with a double-digit table. While measuring the resistivity, another digital meter (with an accuracy of several ten thousandths) monitors the current change in time, eliminating the conversion between the measured current and the measured resistivity, and controlling the measured current in time. The host also provides a constant current source with an accuracy of 0.05%, which makes the measuring current highly stable. This machine is equipped with a constant current source switch, which can avoid the contact spark between the probe tip and the measured material when measuring some thin materials, and better protect the foil. The instrument is equipped with our company's patented product: "Small Wandering Four Probes", and the probe wandering rate is 0. 1 ~ 0.2%. The repeatability and accuracy of instrument resistivity measurement are ensured. If this machine is equipped with HQ-7 10E data processor, it can automatically correct the thickness, diameter and probe spacing when measuring silicon wafers, and calculate and print out the maximum percentage change, average percentage change and radial resistivity unevenness of silicon wafers, which brings great convenience to the measurement.
2. The structure and working principle of the tester
The tester host consists of main board, power board, front panel, back panel and chassis. Voltmeter, ammeter, current regulating potentiometer, constant current source switch and various selector switches are all installed on the front panel (see Figure 2). Only one power socket, one power switch, one four-probe connection socket, one data processor connection socket and one safety tube are installed on the backplane (see Figure 3). The main board and the power board are installed on the chassis, and they are connected with each other through connectors. The working principle of the instrument is shown in figure 1:
The basic principle of the tester is still that the constant current source provides the probe with a stable measuring current I (monitored by the DVM 1 4 probe), and the probe (2, 3) measures the potential difference V (measured by DVM2). The resistivity of a material can be calculated by the following formula:
Samples with a thickness less than 4 times the probe spacing can be calculated by the following formula.
Where: v —— reading of dvm2, mV.
I reading of dvm 1, mA.
W—— the thickness value of the tested sample, in centimeters (cm).
F(W/S)—— Thickness correction factor, the value of which is shown in Appendix II.
F(S/D)—— Diameter correction factor, the value of which is shown in Appendix III.
FSP probe spacing correction coefficient.
FT-temperature correction coefficient, the value of which is shown in Appendix 1.
Because the decimal point processing link is already in this machine, there is no need to consider the units of current and voltage when using it. If the user is equipped with HQ-7 10E data processor, as long as the relevant parameters such as thickness W, FSP and measured current I are put in, all calculations and records will be completed by it. If there is no data processor (HQ-7 10E), users can also calculate the accurate sample resistivity with a common calculator according to the above formula.
For samples or ingots with a thickness greater than 4 times the probe spacing, the resistivity can be calculated as follows:
ρ=2πSV/I (2)
This is a well-known classical formula, in which the thickness of the sample and the distance from any probe to the boundary of the sample are more than 4 times the probe spacing (the boundary condition is approximately semi-dome-free), and there is no need to directly correct the thickness. At this time, if the probe with the spacing of S= 1mm is used, the current I is 0.628; The probe S= 1.59mm, the current I is 0.999, and the resistivity can be read directly from the voltmeter (DVM2) of this instrument.
When KDY- 1 is used to measure the square resistance of conductive film, silicon heteroepitaxial layer, diffusion layer and conductive film, the volume calculation formula is:
FSP
Because the conductive layer is very thin, F(W/S)= 1, it is only necessary to select the current I=F(D/S) FSP, and F(D/S)=4.532.
When measuring, the current is adjusted to 04532, and ρ/R is selected when the R lamp is on.
From the voltmeter (DVM2) on the right of KDY- 1, the square resistance r of the diffusion thin layer can be read directly.
Remarks: When measuring the block resistance, ρ/R should be selected as R. Only when the current is 0.0 1mA, the last digit of the voltmeter overflows (other gears can read normally), so attention should be paid to reading. If the current is 0.0 1, the voltmeter should read 00 1230.
3. How to use it
(1) Introduction of Main Panel and Backplane
All the control parts of the instrument except the power switch are installed on the back plate, and all the display and control parts related to measuring current are concentrated on the left side of the panel. The ammeter (DMV 1) displays the current value of each gear, and the current selection value (with button) is used for power flow selection. After turning on the ~ 220 V power supply, the instrument automatically selects the common gear of 1.0mA, which is above 1.0 at this time. Turn on the constant current source, the indicator light above will light up, the ammeter will display the current value, adjust the coarse adjustment knob to make the first three digits reach the target value, and then adjust the fine adjustment knob to make the last two digits reach the target value. In this way, the current adjustment is completed. At this time, you can focus on the right. All control elements related to voltage measurement are concentrated on the right side of the panel, and the voltmeter (DMV2) displays the forward and reverse voltage measurement values of each gear (ρ/R manual/automatic). ρ/R key must be selected correctly, otherwise the measured values will be different by 10 times; Similarly, the manual/automatic gear must be selected correctly, otherwise the instrument will refuse to work.
Cable sockets are mainly installed on the backboard, and are clearly marked on the drawings. Please pay attention to the alignment mark between the plug and the socket when installing. Because the back is easy to leak, it is not easy to be found if it is loose, so the installation must be fully inserted and firmly inserted.
(2) Before using the instrument, connect the power cord, the connecting wire of the test rack and the connecting wire between the host and the data processor (if the processor is used), and pay attention to whether the probe head is connected to the test rack. After the power cord plug is inserted into the ~ 220 V socket, turn on the power switch on the back panel. At this time, the digital meter and LED on the front panel will light up. Press the probe on the measured single crystal and turn on the switch of constant current source. The instrument on the left shows the measured current flowing into the single crystal from the 1 and 4 probes, and the instrument on the right shows the resistivity (when measuring the single crystal ingot) or the potential difference between the 2 and 3 probes. Adjust the current by rotating the two potentiometer knobs at the lower left of the front panel. Other forward and reverse measurements, ρ/R selection and automatic/manual measurements are controlled by the self-locking button switch on the front panel.
(3) The measuring current of the instrument is divided into five grades: 0.0 1mA( 10μA), 0. 1mA( 100μA), 1mA, 10mA, and the reading.
When the file 0.0 1mA shows 5 digits: 10000 indicates that the current is 0.0 1mA( 10μA).
Another example is shown in the 0.0 1mA file: 06282 indicates that the current is 6.28 μ A.
When the file 0. 1mA displays 5 digits: 10000 indicates that the current is 0. 1mA( 100μA).
Another example is shown in the 0. 1mA file: 04532 indicates that the current is 45.32 μ A.
When five digits are displayed in the 1mA file: 10000 indicates that the current is 1mA.
For another example, the file 1mA shows that 06282 indicates that the current is 0.6282mA.
It is also displayed at 10000: 10000 indicates that the current is1000 mA.
Display: 04532 indicates that the current is 4.532mA.
100mA file shows that: 10000 means the current is 100mA.
Display: 06282 indicates that the current is 62.82mA.
The current gear is selected in a cyclic and step-by-step manner. There is a current selection button on the dashboard. Every time you press it to enter a gear, the instrument will be automatically set at the commonly used 1.0mA gear after starting. If you keep pressing the "Current Selection" button, the current gear will cycle continuously in the following order.
1.0ma→ 10mA→ 100ma→0.0 1mA→0. 1mA→ 1.0ma→ 10mA→……
You can quickly find the equipment you need.
(4) Voltmeter reading: In order to read the resistivity directly with the voltmeter, we artificially changed the decimal point displacement of the voltmeter. If the voltage value needs to be read directly, it should be noted that this voltmeter is a digital voltmeter of 199.99mV, and the decimal point is fixed when reading the voltage value.
For example, a voltmeter displays the reading voltage value.
1.9999 199.99 mv
19.999 199.99 mv
199.99
1999.9 199.99 mv
19999 199.99 mv
According to the national standard GB/T 1552- 1995, the required current values of silicon samples with different resistivity are shown in the following table:
Resistivity, ω. Cm current, the current value recommended by mA for disc measurement.
& lt0.03 ≤ 100 100
0.03 ~ 0.30 & lt 100 25
0.3~3 ≤ 10 2.5
3~30 ≤ 1 0.25
30~300 ≤0. 1 0.025
300~3000 ≤0.0 1 0.0025
According to the standard method of ASTM F374-84, the current value required to measure the block resistance is shown in the following table:
Square resistance ω current, mA
2.0~25 10
20~250 1
200~2500 0. 1
2000~25000 0.0 1
(5) The constant current source switch is only used when it is found that there is voltage in contact between the probe and the measured material, which affects the measured data (or material properties), that is, the probe is pressed against the measured material first, and then the constant current source switch is turned on to avoid instantaneous fire during contact. In order to improve the working efficiency, if the probe strip voltage is in contact with the measured material and has no influence on the measurement, the constant current source switch can always be in the open state.
(6) Forward and reverse measuring switches can only work in manual mode and are controlled by data processor in automatic mode. Therefore, when the manual forward and reverse switch doesn't work, first check whether the manual/automatic switch is in manual mode. On the contrary, when the data processor is used to measure the resistivity of materials, the instrument must be in an automatic state, otherwise the data processing will refuse to work.
(7) When using the data processor for automatic calculation and recording, you must operate in strict accordance with the instructions for use, paying special attention to the number of digits of the input data. In order to use the data processor, please read the operating instructions of KDY measurement system carefully.
4. Host technology can count.
(1) measuring range:
Measurable resistivity: 0.000 1 ~ 19000ω? centimetre
Measurable square resistance: 0.001~190000Ω? □
(2) Constant current source:
Output current: DC 0.00 1 ~ 100 mA, with five gears continuously adjustable.
Range: 0.00 1 ~ 0.0 1ma
0.0 1~0. 10mA
0. 10 ~ 1.0 mA
1.0~ 10mA
10 ~ 100 mA
Constant current accuracy: all gears are below 0.05%.
(3) DC digital voltmeter:
Measuring range: 0 ~ 0 ~199.99mV.
Sensitivity:10 μ v v.
Basic error: (0.004% reading +0.0 1% full scale)
Input impedance: ≥ 1000mω
(4) Power supply:
Ac 220v 10% 50/60hz power: 12W.
(5) Use environment:
Temperature: 23 2℃ Relative humidity: ≤65%
No strong electric field interference, power isolation and filtering, no direct light.
(6) Weight and volume:
Main engine weight: 7.5 kg
Volume: 365×380× 160 (unit: mm length× width× height)
Appendix 1. 1
Temperature correction coefficient table ρT = FT *ρ23
Nominal resistivity
ω. cm
Temperature feet
c 0.005 0.0 1 0. 1. 1.5 10
10
0.9768 0.9969 0.9550 0.9097 0.90 10 0.90 10
12 0.9803 0.9970 0.96 17 0.9232 0.9 157 0.9 140
14 0.9838 0.9972 0.9680 0.9370 0.9302 0.9290
16 0.9873 0.9975 0.9747 0.9502 0.9450 0.9440
18 0.9908 0.9984 0.98 15 0.9635 0.9600 0.9596
20 0.9943 0.9986 0.9890 0.9785 0.9760 0.9758
22 0.9982 0.9999 0.9962 0.9927 0.9920 0.9920
23 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000
24 1.00 16 1.0003 1.0037 1.0075 1.0080 1.0080
26 1.0045 1.0009 1.0 107 1.0222 1.0240 1.0248
28 1.0086 1.00 16 1.0 187 1.0365 1.0400 1.04 10
30 1.0 12 1 1.0028 1.0252 1.0524 1.0570 1.0606
Note: ① The data of temperature correction coefficient table comes from China Institute of Metrology.
Appendix 1.2
Table of temperature correction coefficient (continued 1) ρT = FT *ρ23
Nominal resistivity
ω. cm
Temperature feet
C 25
( 17.5—49.9) 75
(50.0— 127.49) 180
( 127.5—2 14.9) 250/500/ 1000
( ≥ 2 15 )
10 0.9020 0.90 12 0.9006 0.892 1
12 0.9 138 0.9 138 0.9 140 0.9087
14 0.9275 0.9275 0.9278 0.9253
16 0.9422 0.9425 0.9428 0.94 19
18 0.9582 0.9580 0.9582 0.9585
20 0.9748 0.9750 0.9750 0.975 1
22 0.99 15 0.9920 0.9922 0.99 19
23 1.0000 1.0000 1.0000 1.0000
24 1.0078 1.0080 1.0082 1.0083
26 1.0248 1.025 1 1.0252 1.0249
28 1.0440 1.0428 1.04 14 1.04 15
30 1.0600 1.06 10 1.06 12 1.058 1
Appendix II.
The thickness correction coefficient F(W/S) is a function of the ratio of the wafer thickness w to the probe pitch s.
West method, west method, west method, west method, west method, west method.
0.40 0.9993
0.4 1 0.9992
0.42 0.9990
0.43 0.9989
0.44 0.9987
0.45 0.9986
0.46 0.9984
0.47 0.998 1
0.48 0.9978
0.49 0.9976
0.50 0.9975
0.5 1 0.997 1
0.52 0.9967
0.53 0.9962
0.54 0.9958
0.55 0.9953
0.56 0.9947
0.57 0.994 1
0.58 0.9934
0.59 0.9927 0.60 0.9920
0.6 1 0.99 12
0.62 0.9903
0.63 0.9894
0.64 0.9885
0.65 0.9875
0.66 0.9865
0.67 0.9853
0.68 0.9842
0.69 0.9830
0.70 0.98 18
0.7 1 0.9804
0.72 0.979 1
0.73 0.9777
0.74 0.9762
0.75 0.9747
0.76 0.973 1
0.77 0.97 15
0.78 0.9699
0.79 0.968 1 0.80 0.9664
0.8 1 0.9645
0.82 0.9627
0.83 0.9608
0.84 0.9588
0.85 0.9566
0.86 0.9547
0.87 0.9526
0.88 0.9505
0.89 0.9483
0.90 0.9460
0.9 1 0.9438
0.92 0.94 14
0.93 0.939 1
0.94 0.9367
0.95 0.9343
0.96 0.93 18
0.97 0.9293
0.98 0.9263
0.99 0.9242 1.0 0.92 1
1.2 0.864
1.4 0.803
1.6 0.742
1.8 0.685
2.0 0.634
2.2 0.587
2.4 0.546
2.6 0.5 10
2.8 0.477
3.0 0.448
3.2 0.422
3.4 0.399
3.6 0.378
3.8 0.359
4.0 0.342
Note: ① The data of thickness correction coefficient table comes from national standard GB/T 1552- 1995.
Determination of resistivity of silicon and germanium single crystals by in-line four-probe method
Appendix 3.
The correction coefficient F2 is a function of the ratio of the probe pitch s to the wafer diameter d.
France-France-France-France
0 4.532
0.005 4.53 1
0.0 10 4.528
0.0 15 4.524
0.020 4.5 17
0.025 4.508
0.030 4.497 0.035 4.485
0.040 4.470
0.045 4.454
0.050 4.436
0.055 4.4 17
0.060 4.395
0.065 4.372 0.070 4.348
0.075 4.322
0.080 4.294
0.085 4.265
0.090 4.235
0.095 4.204
0. 100 4. 17 1
Note: ① The data of thickness correction coefficient table comes from national standard GB/T 1552- 1995.
Determination of resistivity of silicon and germanium single crystals by in-line four-probe method