Method and apparatus for scanning transmission electron microscopy

A scanning transmission electron microscopy apparatus, comprising:

• an electron source means for generating electrons;
• an electron extracting means for extracting an accelerated primary electron beam from said electron source means, said electron extracting means includes an electron accelerating electrode assembly for accelerating said primary electron beam;
• an electron illuminating system for illuminating said accelerated primary electron beam extracted from said electron source means onto a specimen to be observed, the electron illuminating system includes an electron converging lens system for converging said accelerated primary electron beam and an objective lens system for demagnifying and illuminating said accelerated and converged primary electron beam onto said specimen;
• a specimen holder for holding said specimen;
• a first electron deflecting system for scanning said specimen with said accelerated primary electron beam illuminated onto said specimen;
• a secondary electron detector for detecting secondary electrons released from said specimen;
• a second electron deflecting system for scanning said accelerated primary electron beam on the upper surface of said objective lens, the second electron deflecting system is disposed between said electron accelerating electrode assembly and said electron converging lens system;
• an alignment means for aligning said accelerated primary electron beam to said optical axis of the scanning transmission electron microscopy apparatus in response to the detection signal of said secondary electron detector which is obtained when said accelerated primary electron beam is being scanned by said second electron deflecting system.

A scanning transmission electron microscopy apparatus, comprising:

• an electron source means for generating electrons;
• an electron extracting means for extracting an accelerated primary electron beam from said electron source means, said electron extracting means including an electron accelerating electrode assembly for accelerating said primary electron beam;
• an electron illuminating system for illuminating said accelerated primary electron beam extracted from said electron source means onto a specimen to be observed, said electron illuminating system including an electron converging lens system for converging said accelerated primary electron beam and an objective lens system for demagnifying and illuminating said accelerated and converged primary electron beam onto said specimen;
• a specimen holder for holding said specimen;
• a first electron deflecting system for scanning said specimen with said accelerated primary electron beam illuminated onto said specimen;
• a scattered electron detector for detecting scattered electrons transmitted through said specimen;
• a secondary electron detector for detecting secondary electrons released from said specimen;
• a reflected electron detector for detecting reflected electrons form said specimen;
• and
• a second electron deflecting system for aligning said accelerated primary electron beam to the optical axis of the scanning transmission electron microscopy apparatus, said second deflecting being disposed between said electron accelerating electrode assembly and said electron converging lens system,
• wherein said second electron deflecting system is provided with a scanning deflector and two-stage deflectors with reversal polarity located above and below the scanning deflector, for scanning said accelerated primary electron beam on the upper surface of said objective lens system in order to align said accelerated primary electron beam to the optical axis of said scanning transmission electron microscopy apparatus.

A scanning transmission electron microscopy apparatus comprising:

• an electron source means for generating electrons;
• an electron extracting means for extracting an accelerated primary electron beam from said electron source means, said electron extracting means including an electron accelerating electrode assembly for accelerating said primary electron beam;
• an electron illuminating system for illuminating said accelerated primary electron beam extracted for said electron source means onto a specimen to be observed, said electron illuminating system including an electron converging lens system for converging said accelerated primary electron beam and an objective lens system for demagnifying and illuminating said accelerated and converged primary electron beam onto said specimen;
• a specimen holder for holding said specimen;
• a first electron deflecting system for scanning said specimen with said accelerated primary electron beam illuminated onto said specimen;
• a secondary electron detector for detecting secondary electrons released from said specimen;
• a second electron deflecting system provided with a scanning deflector and two-stage deflectors with reversal polarity located above and below the scanning deflector, for scanning said primary accelerated primary electron beam on the upper surface of said objective lens system, said second deflecting being disposed between said electron accelerating electrode assembly and said electron converging lens system;
• and
• an alignment means for aligning said accelerated primary electron beam to the optical axis of the scanning transmission electron microscopy apparatus in response to the detection signal of said secondary electron detector which is obtained when said accelerated primary electron beam is being scanned by said second electron deflecting system.