Abstract: A device for oscillation excitation of a leaf spring, which is fastened on one side in an atomic force microscope (AFM) and comprises semiconductor material, which has no piezoelectric properties, a free end to which a tip is attached, which is brought into contact with a sample surface to be examined. The present invention has the leaf spring connected at least sectionally to a metal layer to form a Schottky contact, and an electrical voltage or field source is provided, which generates an electrical AC voltage a vicinity or area of the Schottky contact.

Abstract: A device for oscillation excitation of a leaf spring, which is fastened on one side in an atomic force microscope (AFM) and comprises semiconductor material, which has no piezoelectric properties, a free end of which a tip is attached, which may be brought into contact with a sample surface to be examined. The present invention has the leaf spring connected at least sectionally to a metal layer to form a Schottky contact, and an electrical voltage or field source is provided, which generates an electrical AC voltage a vicinity or area of the Schottky contact.

Abstract: A method is described for determining a dopant concentration on a surface and/or in layer region lying close to the surface of a semiconductor sample using an atomic force microscope, whose leaf-spring tip is brought into contact with the semiconductor sample, forming a Schottky barrier, wherein an electric alternating potential is applied between the spring-leaf tip and the semiconductor sample in the region of the Schottky barrier in such a way that a space charge region inside the semiconductor sample defining the three-dimensional extension of the Schottky barrier is excited and begins to oscillate within the confines of its spatial extension, said oscillations are transmitted to the leaf-spring, are detected and form the basis for determining the dopant concentration.

Abstract: A method for exciting free torsional vibrations a spring cantilever, which is clamped in on one side and has a longitudinal extension, of an atomic force microscope (AFM) is disclosed. The invention provides by the one-sidedly clamped-in spring cantilever being placed at a distance over a surface between which and the spring cantilever there is an acoustic coupling medium, by the surface being set into oscillations which are oriented laterally to the surface and are polarized linearly along an oscillation direction, and by the polarization axis given by the oscillation direction being oriented perpendicular to the longitudinal extension of the spring cantilever.

Abstract: A method is described for determining a dopant concentration on a surface and/or in layer region lying close to the surface of a semiconductor sample using an atomic force microscope, whose leaf-spring tip is brought into contact with the semiconductor sample, forming a Schottky barrier, wherein an electric alternating potential is applied between the spring-leaf tip and the semiconductor sample in the region of the Schottky barrier in such a way that a space charge region inside the semiconductor sample defining the three-dimensional extension of the Schottky barrier is excited and begins to oscillate within the confines of its spatial extension, said oscillations are transmitted to the leaf-spring, are detected and form the basis for determining the dopant concentration.

Abstract: A method for examining a surface of a sample is described using an atomic force scanning microscope (AFM) comprising a cantilever with a longitudinal extension along which a measuring tip is disposed, which is selectively arranged relative to the sample surface by a means for driving and whose spatial position is detected using a sensor unit. Vibration excitation is conducted at excitation amplitudes which produce inside the cantilever torsional amplitudes with maximum values which form a largely (substantively) constant plateau value despite increasing excitation amplitudes and the resonance spectra, in a range of maximum values of the torsional amplitudes, a widening of the resonance spectrum which is determinable by a plateau width. The resonance spectra, preferably the plateau value, the plateau width and/or the gradient of the respective resonance spectra are used for examining the sample.

Abstract: Described is a method for examining a surface of a sample using an atomic force scanning microscope (AFM) comprising a cantilever with a longitudinal extension along which a measuring tip is disposed, which is selectively arranged relative to said sample surface by a driver means and whose spatial position is detected using a sensor unit, and said microscope is provided with at least one ultrasound generator, which initiates vibration excitation at a given excitation frequency between said sample surface and said cantilever, the measuring tip of which is brought into contact with said sample surface in such a manner that said measuring tip is excited to vibrations which are oriented lateral to said sample surface and perpendicular to said longitudinal extension of said cantilever and that the torsional vibrations induced in said cantilever are detected and analyzed by means of an evaluation unit.

Abstract: An ultrasonic microscope for acquiring data from internal regions of a sample body is provided. The ultrasonic microscope includes an ultrasonic transmitter for providing a point source of ultrasonic waves for input-coupling into a sample body at a point in proportion to the dimensions of the sample body. Ultrasonically-induced excursions of a receiving tip can be detected with atomic resolution by using an ultrasonic detector that measures with high sensitivity resolution. The ultrasonic transmitter and the ultrasonic detector may be positioned relative to one another such that the ultrasonic detector can adopt several receiving positions for each transmitting position of the ultrasonic transmitter. A measurement data signal from the ultrasonic detector is stored and processed in a central processor. An image generator within the central processor uses a tomographic algorithm to reconstruct an image of at least one area inside the sample body from the measurement data.

Abstract: Selection of Streptomyces viridochromogenes DSM 4112 for resistance to phosphinothricyl-alanyl-alanine (PTT) results in PTT-resistance selectants. The DNA fragment which carries the phosphinothricin(PTC)-resistance gene is obtained from the total DNA of these selectants by cutting with BamHI, cloning of a fragment 4.0 kb in size, and selection for PTT resistance. This gene is suitable for the production of PTC-resistant plants, and as a resistance marker and for the selective N-acetylation of the L-form of racemic PTC.

Abstract: An acoustic microscope allowing both the topography and the elasticity of a sample to be measured at the same time. To this end the displacement of a cantilever with a tip is measured by the deflection of a laser beam. In order to measure the topography, the average deviation of the tip is held constant by a regulation circuit. The regulation circuit consists of a split-photodiode which supplies a neutral signal to the output of a normalizing amplifier which delivers a neutral value. Deviations from this neutral signal are compensated by a z-electrode of a piezocrystal. The elastic properties of the sample are measured by coupling ultrasound into the sample by means of a transducer and the high-frequency displacements of the cantilever with the tip are detected by a second detection device that consists of knife-edge detector and a fast photodiode. The detection device may also consist of a heterodyne time-of-flight interferometer or a capacitive detection scheme.

Abstract: An acoustic microscope allowing both the topography and the elasticity of a sample to be measured at the same time. To this end the displacement of a cantilever with a tip is measured by the deflection of a laser beam. In order to measure the topography, the average deviation of the tip is held constant by a regulation circuit. The regulation circuit consists of a split-photodiode which supplies a neutral signal to the output of a normalizing amplifier which delivers a neutral value. Deviations from this neutral signal are compensated by a z-electrode of a piezocrystal. The elastic properties of the sample are measured by coupling ultrasound into the sample by means of a transducer and the high-frequency displacements of the cantilever with the tip are detected by a second detection device that consists of knife-edge detector and a fast photodiode. The detection device may also consist of a heterodyne time-of-flight interferometer or a capacitive detection scheme.

Abstract: Selection of Streptomyces viridochromogenes DSM 4112 for resistance to phosphinothricyl-alanyl-alanine (PTT) results in PTT-resistance selectants. The DNA fragment which carries the phosphinothricin(PTC)-resistance gene is obtained from the total DNA of these selectants by cutting with BamHI, cloning of a fragment 4.0 kb in size, and selection for PTT resistance. This gene is suitable for the production of PTC-resistant plants, and as a resistance marker and for the selective N-acetylation of the L-form of racemic PTC.

Abstract: The phosphinothricin (PTC)-resistance gene isolated from the genome of Streptomyces viridochromogenes DSM 40736 is, after adaptation to the codon usage in plants, synthesized and incorporated into gene structures which make plants resistant to PTC after expression therein.

Abstract: Selection of Streptomyces viridochromogenes DSM 4112 for resistance to phosphinothricyl-alanyl-alanine (PTT) results in PTT-resistance selectants. The DNA fragment which carries the phosphinothricin(PTC)-resistance gene is obtained from the total DNA of these selectants by cutting with BamHI, cloning of a fragment 4.0 kb in size, and selection for PTT resistance. This gene is suitable for the production of PTC-resistant plants, and as a resistance marker and for the selective N-acetylation of the L-form of racemic PTC.