Apparatus based on a nanowire cross for measuring small potentials of a sample, method for producing the apparatus, and use of the apparatus

6:

• A method for producing an apparatus for measuring electrical potentials of a liquid sample, the apparatus comprising at least one field effect transistor with source, drain and gate, the method comprising:
• arranging a semiconductive layer on a substrate;
• arranging, using a mask with a cross-shaped structure,
• at least two intersecting semiconductive nanowires in the semiconductor layer as a field effect transistor in an anisotropic etching process,
• wherein a cross section of the two nanowires has the shape of a triangle or trapezium,
• wherein source and drain contacts are arranged on each nanowire,
• wherein a voltage applicator configured to apply a voltage to the substrate is arranged on the substrate,
• wherein, on the surface of the nanowires, a dielectric layer having a layer thickness of between 5 and 40 nm is arranged,
• wherein in this dielectric layer, by way of electromagnetic radiation, at least one impurity is selectively produced as a bearing point which is capable of capturing charge carriers from at least one of the two nanowires and, conversely, of emitting the charge carriers to the at least one of the two nanowires.

9:

• The method according to claim 6,
• characterized by the steps:
• a) at least one semiconducting layer is arranged on a substrate,
• b) a pattern of a virtual or physical mask is provided, said pattern comprising two axially symmetrical structures along their longitudinal axis which intersect and each have at least one overall or sectional rectangular or square shape,
• c) an etchant, which anisotropically etches the material of the semiconducting layer, is applied to at least one edge of a surface on the semiconducting layer which is congruent with the total surface area of the pattern,
• d) step c) is repeated for opposite edges of the border of the surface mentioned in step c) until at least two intersecting nanowires of triangular or trapezoidal cross-section are arranged along the longitudinal axes of the surface with a source and/or drain elevation arranged at each end of the nanowires,
• e) a dielectric layer is arranged along the surface of the nanowires,
• f) at least one bearing point is arranged in the dielectric layer along the surface of the wires,
• g) the elevations intended for drain and source and the substrate are electro-conductively connected with means for applying a voltage.

10:

• The method according to claim 9, wherein the arrangement of the etchant according to step c) is carried out in the following sub-steps:
• i) the etchant is arranged at least at a first edge of the surface mentioned in step c), wherein no etchant is arranged at least between the longitudinal axis of this surface which is parallel to the first edge and a second edge opposite the first edge,
• ii) the etchant is removed and subsequently arranged at least at the second edge, wherein at least between the longitudinal axis from step i) and the first edge no etchant is arranged,
• iii) the etching process in steps i) and ii) is carried out according to step d).

11:

• The method according to claim 9, wherein the arrangement of the etchant in step c) is carried out in the following steps:
• i) at least one further layer is arranged on the semiconducting layer, said layer comprising a material which can be removed after irradiation with electron beams and/or light beams and/or ion beams,
• ii) a mask is provided which has at least one surface that matches the total surface area of the pattern,
• iii) the further layer is irradiated with electron beams and/or light and/or ion beams through the mask,
• iv) the regions of the further layer, which have been irradiated through the mask, are removed,
• v) the etchant is arranged at least on the surface of the semiconducting layer on the surface, on which the removed regions of the further layer were arranged,
• vi) the process is continued according to step d), wherein the etchant is arranged at the edges of the surface of step c) in each case after using a mask according to step ii).