Abstract: A high-sensitivity surface wave gas sensor in which the interaction of a surface wave field with a solid film suitable for adsorbing the gas to be determined causes a change in the frequency of an oscillating circuit containing a surface wave delay line as a function of the type and concentration of the gas entails the delay line provided for adsorption of the gas being completely coated with the solid film, and the dimensions of the delay lines being such that the length of the surface wave transformer is greater than that of the delay line.

Abstract: This invention enables examination of semi-conductor chips either on a planar basis or on a three-dimensional basis to determine the characteristics of the chips. Laser light is passed through a first pinhole and is focussed on a wafer. The light reflected from the wafer is passed through a second pinhole and is focussed on a photomultiplier. The focal length between the first pinhole and the wafer is the same as the focal length between the second pinhole and the multiplier. This arrangement provides for a high signal-to-noise ratio to be produced and image information data to be provided within minimal time lags such as a small fraction of a second. An electrically controllable active mirror operable within the beam-shaping optics of the scanning field may be included to displace the plane of the examination field. This active mirror may be controlled to assume the shape of different types of mirrors including a planar mirror.

Abstract: An energy (i.e. laser) beam directed to a photoresist layer is scanned in a first direction through lines progressively displaced in a second coordinate direction. In this way, stripe areas of a wafer are exposed sequentially in a first direction with a thickness dependent upon the size of the laser spot focussed on the beam. The beam scanning rate is adjustable to obtain a time coincidence between the occurrence of markers in a computer and the scanning of a particular position in each line. The beam is modulated during the scan to inscribe a pattern on the layer. The beam is focussed on, and reflected from, the photoresist layer. The reflection is used to maintain the focussing of the beam on the layer by adjusting individual elements in an active mirror in accordance with the reflected beam characteristics.

Abstract: A method of calorimetric absorption spectroscopy (CAS) is claimed, wherein a sample, irradiated with a measuring-light pulse of a specified power, duration, and wavelength and whose absorbance at the specific wavelength of the measuring light is determined as a result of the heating of the sample which occurs as a result of the absorption of a portion of the measuring light, is cooled to a temperature which is so low that the specific heat of the sample during measurement is only a small fraction of the value at normal temperature. This produces an increase in sensitivity by a factor of more than 10.sup.5. The manner in which the lifetime of radiant and nonradiant recombination can be determined in a simple fashion is claimed for samples which have a first impurity center, capable of recombination both by radiation and without radiation, and a second center, capable of recombination only without radiation.