Scanning capacitance microscope

Claim 1

A method for determining variations in the topography and material properties of the surface layer of a body of material comprising: (a) scanning said surface layer with a capacitance probe to generate a first signal representing capacitance variations between the surface layer and said probe; (b) scanning a recording medium in synchronism with the scanning of the surface layer with said probe; (c) recording said first signal on the recording medium as a second signal; and (d) generating a visual display from said second signal from said recording medium presenting thereby capacitance variations as visually discernible variations of an image consisting of points which correlate on a one-to-one basis with points on the surface layer, the image variations manifesting features of the surface layer which cause variations in capacitance between the surface layer and the capacitance probe.

Claim 2

A method for determining variations in the topography and material properties of the surface layer of a body of material comprising: (a) scanning said surface layer with a capacitance probe to generate a first signal representing capacitance variations between the surface layer and said probe; (b) scanning a recording medium in synchronism with the scanning of the surface layer with said probe; (c) recording said first signal on the recording medium as a second signal; and (d) generating a visual display from said second signal from said recording medium presenting thereby capacitance variations as visually discernible variations of an image consisting of points which correlate on a one-to-one basis with points on the surface layer, the image variations manifesting features of the surface layer which cause variations in capacitance between the surface layer and the capacitance probe.

Claim 6

A method for determining variations in the topography and material properties of the surface layer of a disc upon which is impressed a spiral groove, comprising the steps of: (a) rotating said disc about a vertical axis; (b) scanning said surface layer by a capacitance probe having an electrode riding in said groove, thereby generating a scan of the disc in radius and angle to generate a capacitance signal; (c) recording said signal as an image on photographic film by (c1) generating an x-y raster scan of a cathode ray tube in synchronism with the radius and angle scan of said surface layer of said disc; (c2) modulating the intensity of the cathode ray tube beam with said signal to display thereby capacitance variations as visually discernible variations of an image consisting of points which correlate on a one-to-one basis with points on the surface layer, the image variations manifesting features of the surface layer which cause variations in capacitance between the surface layer and the capacitance probe; and (c3) photographing the image displayed on the face of the cathode ray tube.

Claim 7

A method for determining variations in the topography and material properties of the surface layer of a disc upon which is impressed a spiral groove, comprising the steps of: (a) rotating said disc about a vertical axis; (b) scanning said surface layer by a capacitance probe having an electrode riding in said groove, thereby generating a scan of the disc in radius and angle to generate a capacitance signal; (c) recording said signal as an image on photographic film by (c1) generating an x-y raster scan of a cathode ray tube in synchronism with the radius and angle scan of said surface layer of said disc; (c2) modulating the intensity of the cathode ray tube beam with said signal to display thereby capacitance variations as visually discernible variations of an image consisting of points which correlate on a one-to-one basis with points on the surface layer, the image variations manifesting features of the surface layer which cause variations in capacitance between the surface layer and the capacitance probe; and (c3) photographing the image displayed on the face of the cathode ray tube.

Claim 8

A method for determining variations in the topography and material properties of the surface layer of a disc upon which is impressed a spiral groove, comprising the steps of: (a) rotating said disc about a vertical axis; (b) scanning said surface layer by a capacitance probe having an electrode riding in said groove, thereby generating a scan of the disc in radius and angle to generate a first signal; (c) filtering said first signal with an anti-aliasing filter to provide a second signal; (d) sampling said second signal with an analog to digital converter having a fixed sampling rate which is synchronized to said radius and angle scan of said surface layer to convert said second signal to digital form to provide digital samples of said second signal; and (e) storing said digital samples in a computer memory, said digital samples representing capacitance variations consisting of data points which correlate on a one-to-one basis with points on the surface layer, the capacitance variations representing features of the surface layer which cause variations in capacitance between the surface layer and the probe.

Claim 9

A method for determining variations in the topography and material properties of the surface layer of a disc upon which is impressed a spiral groove, comprising the steps of: (a) rotating said disc about a vertical axis; (b) scanning said surface layer by a capacitance probe having an electrode riding in said groove, thereby generating a scan of the disc in radius and angle to generate a first signal; (c) filtering said first signal with an anti-aliasing filter to provide a second signal; (d) sampling said second signal with an analog to digital converter having a fixed sampling rate which is synchronized to said radius and angle scan of said surface layer to convert said second signal to digital form to provide digital samples of said second signal; and (e) storing said digital samples in a computer memory, said digital samples representing capacitance variations consisting of data points which correlate on a one-to-one basis with points on the surface layer, the capacitance variations representing features of the surface layer which cause variations in capacitance between the surface layer and the probe.

Claim 12

The method according to claims 5, 6, 7, or 8 further comprising the step of: before rotating said disc, coating the surface with a conformal metallic layer having a thickness great enough to prevent variations in the mechanical and electrical properties of said surface layer from affecting the capacitance probe whereby only topographical variations in said surface are determined.

Claim 13

A method for determining variations in the electrical properties of the surface layer of a body of material comprising the steps of: (a) scanning said surface layer with a capacitance probe to generate a first signal representing capacitance variations between said surface layer and said probe; (b) scanning a recording medium in synchronism with the scanning of the surface layer with said probe; (c) recording said first signal on the recording medium as a second signal; (d) generating a first image from said second signal corresponding to a predetermined surface portion of said surface layer; (d1) storing said first image in memory; (e) coating said surface layer with a conformal metallic coating having a thickness in excess of the Thomas-Fermi shielding range for electrons in the material comprising the metal of said metallic coating, said coating being thin enough to prevent significant changes in the mechanical properties of said surface layer; (f) after step (e) repeating steps (a) to (c) to generate a third signal representing capacitance variations and recording of said third signal as a fourth signal for generating a second image of said predetermined surface portion; (g) generating said first image from memory; and (h) comparing said first image to said second image to determine variations in electrical properties of said surface as manifested by the presence of features in the first image which are absent in the second image.

Claim 14

A method for determining variations in the electrical properties of the surface layer of a body of material comprising the steps of: (a) scanning said surface layer with a capacitance probe to generate a first signal representing capacitance variations between said surface layer and said probe; (b) scanning a recording medium in synchronism with the scanning of the surface layer with said probe; (c) recording said first signal on the recording medium as a second signal; (d) generating a first image from said second signal corresponding to a predetermined surface portion of said surface layer; (d1) storing said first image in memory; (e) coating said surface layer with a conformal metallic coating having a thickness in excess of the Thomas-Fermi shielding range for electrons in the material comprising the metal of said metallic coating, said coating being thin enough to prevent significant changes in the mechanical properties of said surface layer; (f) after step (e) repeating steps (a) to (c) to generate a third signal representing capacitance variations and recording of said third signal as a fourth signal for generating a second image of said predetermined surface portion; (g) generating said first image from memory; and (h) comparing said first image to said second image to determine variations in electrical properties of said surface as manifested by the presence of features in the first image which are absent in the second image.

Claim 22

A method of microscopy comprising continuously scanning the surface of a body with only one capacitance probe by providing relative movement between the surface and the probe to generate a continous signal representing the variation in capacitance between the body and the probe, and processing the signal to produce an image of the topography and material properties of the surface layer.

Claim 23

A method of microscopy comprising continuously scanning the surface of a body with only one capacitance probe by providing relative movement between the surface and the probe to generate a continous signal representing the variation in capacitance between the body and the probe, and processing the signal to produce an image of the topography and material properties of the surface layer.