Abstract: An atomic force microscope and method of operation are provided and include a force sensing probe tip adapted to be brought into close proximity with a sample surface, a scanning element for generating relative movement between the probe tip and the sample surface, a device for generating a magnetic field to cause deflection of the probe tip, a driver for the device, the driver including a source of alternating current and a source of a second current of a controlled magnitude, and a detector for detecting the position of the probe tip. In a preferred mode of operation, two signals, one of alternating current and the other of a fixed, but variable, current, are applied to cause a displacement of the time-average position of the probe tip.

Abstract: A force sensing cantilever for use in a scanning probe microscope has both a top side and a bottom side. From the bottom side extends a probe tip. The bottom side is coated with a thin film of a first material and the top side is coated with a thin film of a second material. The first and second materials may be the same or they may be different. The materials and thicknesses of the respective films are selected so as to create opposing forces to counter the tendency of such cantilevers to bend when a thin film is applied to only one side thereof.

Abstract: A heater for use in heating a sample stage of a microscope such as a scanning probe microscope is bonded to a sample stage which sits on a tube of a ceramic thermal insulator which is, in turn, mounted within or part of a tube of the same material. This re-entrant design provides an increased thermal path over straight line distances between the heater and the support structure for the sample stage and thus provides excellent thermal insulation, while also maximizing the thermal stability of the system.

Abstract: A scanning probe microscope controller includes a digital signal processor (DSP) and an analog feedback control loop. The DSP serves to process the output of the scanning probe in the digital realm after conversion of the signal to digital form. After processing, the signal is restored to analog form. The height correction signal to be applied to a transducer controlling the distance between the scanning probe and a sample surface is then generated by an analog feedback control circuit, at least one parameter of which is under computer control. At the end of each scan-line, a variance may be calculated for the data and the inverse of this quantity is used to adjust the gain with which digitization of the data is carried out. Linearization of the data to correct for non-linearities in the scanning transducers may be carried out by the DSP after the data is acquired. This permits the scanning ramps applied to the transducers to be linear but the final displayed data do not show the effects of non-linearities.

Abstract: Features for incorporation with scanning probe microscopes are provided which may be used separately or together. The features include constructing the microscope with a hinged top housing providing easy access to the heart of the microscope; a self-aligning and torque limiting magnetic clutch coupling a motor drive powering at least one vertical adjustment screw of the microscope; a removable microscope head for easy adjustment; an optical microscope, optionally mounted to an electronic camera and imaging system, installed adjacent to the head; operation on an inverted microscope stage; bowing error correction; a gas sparging system providing contaminant and noise reduction; a glove box type of loading system so that reactive materials may be safely loaded into the microscope; and a compact desk-top chamber which provides acoustic and vibration isolation.

Abstract: In accordance with a first aspect of the present invention, the sensitivity of a magnetically modulated AC-AFM is substantially improved by the use of a ferrite-core solenoid for modulating the magnetic cantilever of the ACAFM. In accordance with a second aspect of the present invention, the detection system for a magnetically modulated AC-AFM incorporates AC coupling of the signal from the position sensitive detector/beam deflection detector in order to remove the DC component of the signal, resulting in significantly improved dynamic range over systems utilizing DC coupling. High frequency modulation signals are detected through the use of fast analog multipliers which, after active filtering, give a low frequency signal which may be processed by digital electronics. In accordance with a third aspect of the present invention, operation of the microscope at small amplitudes of oscillation leaves small asperities on the tip intact and results in dramatic improvement in resolution.

Abstract: A microscope suitable for use in atomic force microscopy and scanning tunneling microscopy includes an electrochemical liquid cell. Vertically adjustable supporting mounts extend downwardly from a frame and include magnetic balls to which a sample platform may be attached. At least two adjustment pegs extend downwards from the frame and engage the platform for horizontal adjustment at apertures therethrough. The pegs may be moved out of engagement with the platform to reduce drift. An electrical sensor provides a signal to indicate whether the pegs are in contact with the platform. A bore in the frame is provided through which the chosen scanning head may be inserted so as to engage a sample on the platform. A hermetically sealed chamber may be formed around the sample by a seal between the scanner of the microscope and the frame as well as an enclosure which fits over the bottom of the microscope and engages the frame at an O-ring seal. Scanning heads may be rotated for adjustment.

Abstract: Features for incorporation with scanning probe microscopes are provided which may be used separately or together. The features include constructing the microscope with a hinged top housing providing easy access to the heart of the microscope; a self-aligning and torque limiting magnetic clutch coupling a motor drive powering at least one vertical adjustment screw of the microscope; a removable microscope head for easy adjustment; an optical microscope, optionally mounted to an electronic camera and imaging system, installed adjacent to the head; operation on an inverted microscope stage; bowing error correction; a gas sparging system providing contaminant and noise reduction; a glove box type of loading system so that reactive materials may be safely loaded into the microscope; and a compact desk-top chamber which provides acoustic and vibration isolation.

Abstract: A tip and substrate preparation system for use with scanning probe microscopes (SPMs) includes a scanning tunneling microscope (STM) tip maker, STM tip coater, a substrate treatment method for producing clean, flat gold substrates for STM use and methods for preparing chemically activated substrates for use with an atomic force microscope (AFM). The tip maker includes a coater and an etcher which are preferably controlled by electronic controllers. The etcher provides fully automatic tip etching in a two-stage process in sodium hydroxide (NaOH) solution, permitting platinum alloys to be etched without the use of cyanide-containing chemicals. The coater is used to insulate the tips with soft polymer coatings so as to ensure very low tip leakage current (on the order of about 1 pA typical). The substrate treatment device comprises a quartz plate and a quartz torch for annealing substrates in a hydrogen flame.

Abstract: A novel stress cell for applying stress in-situ to a sample in a scanning probe microscope. It has a loading clamp mounted on a sample stage which is magnetically mounted to a scanning tunneling microscope or atomic force microscope. A wedge is placed on top of the sample stage. A clamp holds a sample with its two arms pulling the sample against the wedge. It is fastened by a micrometer which is driven by a motor. A force-sensor is placed between the clamp and the stage to measure the force applied. This cell provides a superior stability and straightforward operation procedure for studying stress related problems in materials.

Abstract: A method and apparatus for high resolution mapping of the chemical composition of a thin film utilizes scanning probe microscopy techniques. The sample to be studied is prepared as a thin film disposed on a conductive backing electrode. A sensitive electrometer is connected to the backing electrode to detect current passing through it. According to a first aspect of the invention, a force sensing cantilever is scanned relative to the sample surface a plurality of times. Topographic information about the sample surface is obtained in a conventional manner by studying deflections of the cantilever or feedback current used to minimize deflections of the cantilever. Simultaneously, a voltage is applied to the probe tip. This voltage, through a tunneling current to the backing electrode, causes reduction and/or oxidation reactions in the sample surface. On successive scans, different voltages may be used.