Ultramicroscopy 0 North-Holland
3 (1978) 169-174 Publishing Company
CONTRIBUTIONTOTHECONTAMINATIONPROBLEMINTRANSMISSIONELECTRON MICROSCOPY L. REIMER and M. WkHTER Physikalisches
Institut,
Universitiit
Miinstcr.
44 Miinster.
Fed. Rep.
Germany
Received 2 January 1978
The contamination of different supporting films is measured by irradiating a circular area of a few pm diameter and by using an electron probe of a few ten nm diameter. Contamination rings are generated by this method. They can be explained by diffusion of the hydrocarbon molecules on the specimen-surface and by adsorption from the vacuum. The influence of specimen heating and charging arc discussed. Some specimen cleaning methods have been examined. The best results were obtained by immersion of the specimen and the cartridge in methanol.
1. Introduction
2. Experimental methods
The problem of contamination in the normal operation mode of a transmission electron microscope (TEM) has been solved satisfactorily by the use of an anticontamination device (ACD) consisting of liquid-nitrogen-cooled blades on both sides of the specimen. However, contamination is again of current interest because of the increasing use of very small beam diameters, as for example in a scanning device for a TEM. The contamination disturbs the convergent beam diffraction patterns obtainable with a stationary electron probe of
3 (1978) 169-174 Publishing Company
CONTRIBUTIONTOTHECONTAMINATIONPROBLEMINTRANSMISSIONELECTRON MICROSCOPY L. REIMER and M. WkHTER Physikalisches
Institut,
Universitiit
Miinstcr.
44 Miinster.
Fed. Rep.
Germany
Received 2 January 1978
The contamination of different supporting films is measured by irradiating a circular area of a few pm diameter and by using an electron probe of a few ten nm diameter. Contamination rings are generated by this method. They can be explained by diffusion of the hydrocarbon molecules on the specimen-surface and by adsorption from the vacuum. The influence of specimen heating and charging arc discussed. Some specimen cleaning methods have been examined. The best results were obtained by immersion of the specimen and the cartridge in methanol.
1. Introduction
2. Experimental methods
The problem of contamination in the normal operation mode of a transmission electron microscope (TEM) has been solved satisfactorily by the use of an anticontamination device (ACD) consisting of liquid-nitrogen-cooled blades on both sides of the specimen. However, contamination is again of current interest because of the increasing use of very small beam diameters, as for example in a scanning device for a TEM. The contamination disturbs the convergent beam diffraction patterns obtainable with a stationary electron probe of
