SJ 3196-1989 Test method for secondary electron emission coefficient of electronic materials SJ3196-1989 standard download decompression password: www.bzxz.net

Standard of the Ministry of Machinery and Electronics Industry of the People's Republic of China SJ3196-89
Test method for secondary electron emission coefficient of electronic materials Published on February 10, 1989
Implemented on March 1, 1989
Test method for secondary electron emission coefficient of electronic materials 1 Subject content and applicable scope
1.1 This standard specifies the determination of secondary electron emission coefficient of electronic materials by electron gun method, SJ3196-89
1.2 This standard applies to all solid electronic materials (including metals, non-metals, semiconductors and insulators). 2 Terms
2.1 Primary electrons
Emitted electrons bombarding the target,
2.2 Secondary electrons
All electrons ejected under the action of the target electron, including real secondary electrons and rebounded primary electrons, etc. 2.3 Secondary electron emission coefficient 5.
The ratio of the secondary electron current value to the primary electron current value, 2.4 Maximum secondary electron emission coefficient 5mmx
The secondary electron emission coefficient of a specific electron material varies with the vertical electron energy: there is a certain energy (Epmax) that makes the secondary electron emission coefficient the maximum value (m)3 Method Summary
Use an electron gun to generate a primary electron flow, vertically bombard the target surface made of the material to be tested, thereby obtaining secondary electrons, which are collected by the collector. The principle of the measuring disk is shown in Figure 1. The ratio of the current value collected by the collector to the primary current value incident on the target surface is the secondary electron emission coefficient. Figure 1 Circuit for measuring secondary electron emission coefficient by electron gun method Approved by the Ministry of Machinery and Electronics Industry of the People's Republic of China on February 10, 1989, and implemented on March 1, 1989 SJ3196-89 K-Cathode of electron gun; A, A-anode; C-collector. M-modulator; D-target; When measuring the secondary electron emission coefficient of conductor materials, the primary electron beam can be used for detection by continuously incident primary electron flow. In order to avoid the influence of surface charging, when measuring the secondary electron emission coefficient of semiconductors, the primary electron beam must bombard the secondary emitter intermittently in a pulsed manner. When measuring the secondary electron emission coefficient of insulators, the primary electron beam adopts single pulse incidence, and the emission current is limited to less than a few microamperes. 4 Measurement equipment High vacuum dynamic test system, as shown in Figure 2. b. Electron gun assembly with collector, see 15 in Figure 2. c. Pulse signal generator.
d. Pulse oscilloscope
e. DC electronic regulated power supply, 02000V, 0--800V.0--24V memory pulse oscilloscope,
micro-ampere meter, concubine ampere meter.
Figure 2 Schematic diagram of dynamic vacuum system
1. Mechanical pump;
2. Solenoid valve:
3. Adsorption pump;
5 Sample preparation
4. Ultra-high vacuum valve;
7. Small cooling pump:
10. Fine-tuning valve;
SJ3196-89
5. Thermocouple bubble, ionization bubble;
8. Release valve:
11. Sample analysis chamber;
13.@50 ultra-high vacuum valve
15. Electron gun with collector:||tt ||17. Adjustable sample holder;
6. Sublimation pump;
9. Ultra-high vacuum valve;
12. BA bubble;
14.2501/8 cold pump
16. Target assembly;
5.1 Cut the material to be tested into 3×3mm square sheets with a thickness of 0.5mm. The maximum allowable size is 10×10mm with a thickness of 6mm
5.2 Polish the surface of the sample to remove mechanical damage. 5.3 Clean the above-mentioned sheets according to the requirements of the parts in the electric vacuum device, such as cleaning, hydrogen burning and degassing.
6 Test steps
6.1 Assemble the sample into a target assembly.
6.2 Insert the target assembly into the sample rack in the analysis chamber of the dynamic vacuum system and adjust it to a certain position relative to the electron gun.
6.3 Evacuate the chamber. When the pressure in the analysis chamber is less than 5×10~P, bake the system for 4 hours. When the pressure is less than 1×10-P, the test can be carried out.
6.4 Turn on the circuit and preheat each instrument for 15 minutes. 6.5 Measure the value of the primary electron current on the incident target (when the collector is at a negative voltage relative to the target). 6.6 Gradually increase the acceleration voltage from zero volts and record the corresponding target current and collector current. 7 Calculation
7.1 The secondary electron emission system 3 is calculated according to the following formula: 5=
Where: I collector current, μA;
I - target current, uA;
I. +I The primary electron current on the target (uA). The designed electron gun has been tested and found that the electron current value is constant within the range of Ep variation.
7.2 3 is the ordinate and Ep is the abscissa. Draw the 8-Ep curve. 7.3 The maximum secondary electron emission coefficient value mx and the corresponding primary electron energy value Epmax are determined from the curve, as shown in Figure 3.
8 Precision
SJ3196-89
Figure 38-Ep curve and calibration of 8mx and Epmax This standard uses a hemispherical collector with a measurement accuracy of 1%; a cylindrical collector with a measurement accuracy of 5% including instrument error, and the total accuracy is within 10%. 8.2
Main sources of error
Instrument instability and drift.
The sample surface is contaminated.
10 PrecautionsbZxz.net
After the sample is cleaned, avoid contamination during the assembly process. 10.1
During the test, the vacuum degree of the analysis room must be maintained to prevent interference from the ion flow. 10.2
10.3 The oscilloscope readings need to be checked frequently. Additional notes:
This standard was drafted by Nanjing Institute of Technology. The main drafters of this standard are Chen Desen and Mo Chunchang. 4
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