摘要:
A mechanical scanning stage for high speed image acquisition in a focused beam system. The mechanical scanning stage preferably is a combination of four stages. A first stage provides linear motion. A second stage, above the first stage, provides rotational positioning. A third stage above the rotational stage is moveable in a first linear direction, and the fourth stage above the third stage is positionable in a second linear direction orthogonal to the first direction. The four stages are responsive to input from a controller programmed with a polar coordinate pixel addressing method, for positioning a specimen mounted on the mechanical stage to allow an applied static focus beam to irradiate selected areas of interest, thereby imaged by collecting signals from the specimen using a polar coordinate pixel addressing method.
摘要:
An improved method of performing optical beam induced current imaging of semiconductor junctions. According to the method, a single wired contact to an integrated circuit (for example through use of a conventional conductive probe) is made at a point that makes electrical contact to a first side of a junction to be analyzed. A first line connects the wired contact to an amplifier, and a second line carries return current from the amplifier to a ground connection. A capacitive return connection is then used to couple return current from a second side of the junction to ground. The actual value of capacitance in the return connection is not of fundamental importance in the practice of the invention, but generally larger capacitance values are preferred and allow increased induced current flow. An increase in the optical beam power also results in more induced current being generated. This causes a faster decay and results in a better signal-to-noise ratio at a higher scanning beam rate. With the connections described above to the amplifier and the processing circuitry, a pulsed particle or optical beam is applied to the junction. In response to the pulsed beam, the junction generates a corresponding pulse of induced current. Since the current in response to the pulsed beam has an alternating current component, it passes through the capacitive junction return connection as well as through the single wired contact to the amplifier. The amplifier outputs a magnified replica of the current which is then analyzed by the processing circuit to provide a useful form of data for analysis of the junction.
摘要:
A parabolic light reflection device in a cathodoluminescence (CL) apparatus is integrated with a photosensitive solid state device mounted on a supporting plate, and supported in an electron microscope vacuum chamber specimen stage by an adaptor element. These components are optically aligned with respect to one another and a readily exchangeable unit is thus obtained. Designed for CL emission operation in an electron microscope, the parabolic light reflection device and the photosensitive solid state detection device are optically aligned and then mounted on a supporting plate of the photosensitive solid state device. The unit thus configured is supported by the specimen stage adaptor element to obtain a mechanical element which can be easily inserted in and removed from any standard electron microscope vacuum chamber stage as a single integrated unit.
摘要:
A mechanical scanning stage for high speed image acquisition in a focused beam system. The mechanical scanning stage preferably is a combination of four stages. A first stage provides linear motion. A second stage, above the first stage, provides rotational positioning. A third stage above the rotational stage is moveable in a first linear direction, and the fourth stage above the third stage is positionable in a second linear direction orthogonal to the first direction. The four stages are responsive to input from a controller programmed with a polar coordinate pixel addressing method, for positioning a specimen mounted on the mechanical stage to allow an applied static focus beam to irradiate selected areas of interest, thereby imaged by collecting signals from the specimen using a polar coordinate pixel addressing method.
摘要:
A mechanical scanning stage for high speed image acquisition in a focused beam system. The mechanical scanning stage preferably is a combination of four stages. A first stage provides linear motion. A second stage, above the first stage, provides rotational positioning. A third stage above the rotational stage is moveable in a first linear direction, and the fourth stage above the third stage is positionable in a second linear direction orthogonal to the first direction. The four stages are responsive to input from a controller programmed with a polar coordinate pixel addressing method, for positioning a specimen mounted on the mechanical stage to allow an applied static focus beam to irradiate selected areas of interest, thereby imaged by collecting signals from the specimen using a polar coordinate pixel addressing method.
摘要:
A method of preparation of a map of areas on a sample that collects charge, and a method for using the map to selectively scan and modulate the intensity of the electron beam of a SEM so as to discriminate between the charging and non-charging areas of the sample. To generate the charging map, an image is first checked for saturation. The frame for the image is acquired by using digital scan control coupled with digital acquisition of the secondary electron detector signal. The next step is to perform a “fast scan” where the first frame is taken at the maximum frame rate that the system is capable of. A fast scan does not allow time for significant charge to collect on surfaces, and this provides a base level to subtract from a slower scan that allows charge to accumulate. Areas where the difference between the two is larger indicate areas of charge collection. A “slow scan” is then performed. The frames are then subtracted pixel-by-pixel in order to isolate the charging component of the image. After the pixel-by-pixel subtraction, the charging map is created. To obtain a more ideal charging map, further image processing is performed to reduce the noise level as well as to merge pixels together to form a fuller representation of a charging feature. The selective deposition process for charging reduction is accomplished by modulating the electron beam intensity to adjust the dosage on a sample based on the charging map. The total charge build-up on the charging areas is controlled by depositing the beam on the charging areas only on selected scans. The non-charging areas are preferably exposed to the beam during every scan, which, together with averaging performed using a plurality of scans, maximizes the S/N (signal-to-noise) ratio.
摘要:
In a method and apparatus for measuring quantitative voltage contrast, an electron beam of the scanning electron microscope is located on a specimen electrode, and a grid voltage of an energy analyzer of the scanning electron microscope is varied. A detector detects secondary electron emission from the specimen electrode. A measured peak voltage of the specimen electrode is determined based on output from the detector. A specimen electrode voltage corrected for type I local field effect error is then obtained using the measured peak voltage and a type I calibration curve. The type I calibration curve represents peak voltage versus specimen electrode voltage. Type II local field effect error in the specimen electrode voltage is then corrected based on a type II calibration curve. The type II calibration curve represents a shift in specimen electrode peak voltage versus adjacent electrode voltage.
摘要:
A parabolic reflector and an inclined planar light reflector in a cathodoluminescence detector are integrated with a set of photo-sensitive solid-state detector cells mounted in quadrature on a supporting plate, and supported by an electron microscope vacuum chamber specimen stage adaptor unit. Designed for CL emission operation in an electron microscope, the parabolic light reflector, the inclined planar light reflector and the photo-sensitive, solid-state detector cells are optically aligned and mechanically combined through the supporting plate of the detector cells. A readily exchangeable unit is thus obtained. The unit is further supported by the specimen stage adaptor unit so as to obtain a mechanical unit which can easily be mounted in and removed from any standard electron microscope vacuum chamber stage as a single integrated unit.