Abstract: A substrate processing apparatus and method are disclosed.

Abstract: An object of the invention is to provide a method and apparatus for observing inside structures and a specimen holder, wherein aging degradation of a good sample to a bad sample can be tracked in the same field of view, using the same specimen in order to determine the mechanism of failure. The present invention is a method for observing inside structures. The method comprises irradiating a specimen with a corpuscular beam generated from a corpuscular beam source, detecting transmitted particles transmitted by the specimen, applying a voltage to a portion of the specimen, and observing of a detection status of the transmitted particles in the voltage-applied portion as needed.

Abstract: A pre-cryogenic electron microscope specimen holder is disclosed. The pre-cryogenic electron microscope specimen holder includes a specimen holding member and a cryogenic energy storing member. The cryogenic energy storing member further includes a liquid gas storing trench formed therein to store the liquid gas. The cryogenic energy storing member is disposed under the specimen holding member to further supply the cryogenic energy to the specimen to extend the observation time for the specimen in an electron microscope.

Abstract: The invention pertains to a method for separating a minute sample (1) from a work piece (2). Such a method is routinely used in the semiconductor industry to obtain samples from wafers to be inspected in a TEM. It occurred to the inventor that approximately 20% of the obtained samples could not be properly finished (thinned) due to a misalignment of specimen carrier (6) and sample. It turned out that this misalignment is caused by the specimen carrier contacting the sample prior to welding. By not contacting the sample while welding, but leaving a small gap between specimen carrier and sample, this misalignment is avoided. To avoid movement of the specimen carrier during welding, due to e.g. vibration, the specimen carrier can be landed on the wafer on a position (8) close to the sample.

Abstract: Provided are an ion implanter for compensating for a wafer cut angle and an ion implantation method using the same. The ion implanter may include an orienter for rotating a wafer mounted on an alignment stage thereof to align a notch of the wafer and a wafer stage for mounting thereon the wafer whose notch has been aligned. The ion implanter may further include an ion implantation angle adjustment unit for adjusting an angle of the wafer stage, a cut angle measurement unit for measuring the wafer cut angle while the wafer is mounted and rotated on the alignment stage, and a controller for controlling the ion implantation angle adjustment unit to compensate for the measured wafer cut angle.

Abstract: A method and apparatus 300 for better controlling scanning of a workpiece 330 through an ion beam path 306 provide for mounting a workpiece 330 on an elongated member, partially repetitively rotating the elongated member 500 around a point of rotation 368 to make repetitive scans of the workpiece 330 along and arcuate path 504 and bending the elongated member 500 at a joint 322 to move the one and out of the ion beam path 306 to facilitate attachment and removal of individual workpieces 330. A motor 315 used for the rotating may be suspended within a partial vacuum enclosure 304 against gravity for raising and lowering the elongated member and 500 a workpiece 306 for linear vertical scanning.

Abstract: An object of the present invention is to provide an electron microscope that employs a hologram of a diffraction pattern to reconstruct a microscopic image involving no imaging aberration due to image forming lenses, as well as a combined illumination lens used for such an electron microscope.

Abstract: A specimen stage apparatus has a braking structure which can generate a braking force enough to stop a specimen stage while keeping a movable table from increasing in its weight. The specimen stage apparatus has an X guide fixed on an X base and representing a guide structure in X direction, an X table constrained by the X guide to be movable in X direction, an X actuator having its movable part fixed to the X table and an X brake fixed to the X base and representing a braking structure for the X table. A controller carries out positioning control in which it generates a braking force by pushing the X brake against the bottom surface of the X table to stop a specimen stage and turning off the servo-control of the X actuator after stoppage of the specimen stage.

Abstract: The present invention relates to a cryo-charging specimen holder for the electron microscope, particularly to a cryo-charging specimen holder for the electron microscope to hold various biological materials. The major feature of the invention is to charge the biological specimen and freeze the specimen at low temperature. The ice around the biological sample is also doped, so that after charging the doped ice surrounding the sample has a conductivity level comparable to that of conductor. Therefore, the sample can be embedded by the doped and charged ice obtaining the property of conductor, in order to be observed by the electron microscope.

Abstract: In a specimen pre-treatment apparatus, a specimen support part is screwed in a hollow column casing part while facing a specimen support end toward the same direction as an open end of the hollow column casing part. A specimen holder is arranged so that the specimen support end which supports a specimen is opposite to an end portion of an anode (electrode). The change of the screwing depth can adjust a position of the specimen support part with respect to the hollow column casing part. Accordingly, it allows adjusting the distance between the specimen that is supported by the specimen support part and the end portion of the anode.

Abstract: A sample stage for electron microscope according to an embodiment of the invention includes at least two actuators capable of expanding and contracting or capable of swinging for moving a target sample in a predetermined direction. With a coordination of the two actuators, various controls are available by combining the operations of the two actuators. Accordingly, a stage mechanism capable of reducing a stop drift as well as moving a stage can be provided.

Abstract: Provided is a charged particle beam processing apparatus capable of improving yields by suppressing the spread of metal pollution to a semiconductor manufacturing process to a minimum. The charged particle beam processing apparatus includes an ion beam column 1 that is connected to a vacuum vessel 10 and irradiates a sample 35 with an ion beam 11 of nonmetal ion species, a microsampling unit 3 having a probe 16 that extracts a microsample 43 cut out from a sample 35 by the ion beam 11, a gas gun 2 that discharges a gas for bonding the microsample 43 and the probe 16, a pollution measuring beam column 6A that is connected to the same vacuum vessel 10 to which the ion beam column 1 is connected and irradiates an ion beam irradiation traces by the ion beam column 1 with a pollution measuring beam 13, and a detector 7 that detects characteristic X-rays emitted from the ion beam irradiation traces by the ion beam column 1 upon irradiation with the pollution measuring beam 13.

Abstract: In a scanning probe apparatus capable of always effectively canceling an inertial force to suppress vibration even in repetitive use while replacing a sample holding table or a probe, a stage for a sample or the probe includes a drive element for moving the sample holding table and movable portions movable in a direction in which an inertial force generated during movement of the sample holding table. The stage is configured so that the drive element, the movable portions, and the sample holding table or the probe are integrally detachably mountable to a main assembly of the scanning probe apparatus.

Abstract: A charged-particle beam system is offered which is equipped with a Z-motion mechanism to enable tomography. The Z-motion mechanism includes a rotary disk having three tapering surfaces on which balls are nested. The rotary disk is rotated via a worm gear to cause the balls to go upward along the tapering surfaces. This pushes an overlying elevatable disk upward, i.e., in the Z-direction. Consequently, the specimen stage is pushed up in the Z-direction.

Abstract: The present invention relates to a device and system from doing mechanical and electrical measurements and manipulation on nano or micro sized objects using a sample holder adapted to fit in situ of a transmission electron microscope. The sample holder comprise at least two arms each with at least one connector whereby the sample (206) may be mounted between the two connectors forming a bridge closing a gap between the two arms of the sample holder. The sample holder is arranged to provide mechanical forces to a sample mounted on the sample holder and measuring and/or applying electrical signals from the sample while at the same imaging using the transmission electron microscope. Each arm of the sample holder may comprise three substantially parallel beams for electro-thermal actuation.

Abstract: A charged particle beam apparatus can be constructed with a smaller size (resulting in a small installation space) and a lower cost, suppress vibration, operate at higher speed, and be reliable in inspection. The charged particle beam apparatus is largely effective when a wafer having a large diameter is used. The charged particle beam apparatus includes: a plurality of inspection mechanisms, each of which is mounted on a vacuum chamber and has a charged particle beam mechanism for performing at least an inspection on the sample; a single-shaft transfer mechanism that moves the sample between the inspection mechanisms in the direction of an axis of the single-shaft transfer mechanism; and a rotary stage that mounts the sample thereon and has a rotational axis on the single-shaft transfer mechanism. The single-shaft transfer mechanism moves the sample between the inspection mechanisms in order that the sample is placed under any of the inspection mechanisms.

Abstract: A sample is evaluated at a high throughput by reducing axial chromatic aberration and increasing the transmittance of secondary electrons. Electron beams emitted from an electron gun 1 are irradiated onto a sample 7 through a primary electro-optical system, and electrons consequently emitted from the sample are detected by a detector 12 through a secondary electro-optical system. A Wien filter 8 comprising a multi-pole lens for correcting axial chromatic aberration is disposed between a magnification lens 10 in the secondary electro-optical system and a beam separator 5 for separating a primary electron beam and a secondary electron beam, for correcting axial chromatic aberration caused by an objective lens 14 which comprises an electromagnetic lens having a magnetic gap defined on a sample side.

Abstract: A scanning probe microscope system comprising a hollow probe 3, a tube 4 connected to a rear end 32 of the hollow probe 3, a support table 1 provided under the hollow probe 3, and a substrate 2 and a means 5 for washing the hollow probe 3 that are fixed to the support table 1, a sample S passing through the tube 4 and the hollow probe 3, and the substrate 2 and the washing means 5 being moved by the support table 1 such that each of them opposes the hollow probe 3.

Abstract: A sample working/observing apparatus possesses a sample holding mechanism. The sample holding mechanism possesses a sample holder holding a sample, and a base detachably supporting the sample holder. Between these, there are detachably provided a rotation support part supporting so as to be rotatable, a slide support part supporting so as to be slidable from a rotation center toward an X-direction, and a butting support part supporting so as to be slidable in the X-direction and a Y-direction. In an upper face, there are provided an X-direction positioning pin and a Y-direction positioning pin, which are disposed along the Y-direction and the X-direction from the rotation center, and butt against one side and the other side of the sample.

Abstract: A wafer holder includes: a frame-shaped holder main body which has an opening at its center and carries a wafer on its upper surface; guide members which contact the outer periphery of the wafer placed on the holder main body and position the wafer on the holder main body; and cross section sample holding members which are disposed on an outer circumference of the holder main body and holds a cross section sample produced from the wafer. Each of the cross section sample holding members includes plate-shaped sample stands to which the cross section sample is fixed, and fixing stands each of which is detachably attached to the holder main body and pinches the sample stand such that the sample stand is attachable to and detachable from the fixing stand.

Abstract: In a scanning probe apparatus capable of always effectively canceling an inertial force to suppress vibration even in repetitive use while replacing a sample holding table or a probe, a stage for a sample or the probe includes a drive element for moving the sample holding table and movable portions movable in a direction in which an inertial force generated during movement of the sample holding table. The stage is configured so that the drive element, the movable portions, and the sample holding table or the probe are integrally detachably mountable to a main assembly of the scanning probe apparatus.

Abstract: An ion implantation system that optimizes productivity that includes an ion generator configured to implant ions into a workpiece by scanning the ions along an axis in a first direction, a movable stage configured to move the workpiece in a second direction generally orthogonal to the first direction, an ion detection component configured to measure ion dosage at approximately an outer edge of the workpiece, a first direction driver that receives commands from the controller to move in a fast scan speed on wafer or a fast scan speed off wafer and a second direction driver that receives commands from the controller to move the workpiece movable stage in a slow scan speed.

Abstract: A specimen holder has two levers on which probes for current measurement are carried. The levers are in contact with a spherical body, the spherical body acting as a pivotal point. When the levers are pushed by micrometer heads, the probes move in the X-direction. When the levers are pulled, the probes are pushed back by springs and move in the ?X-direction. When the first lever is pushed by a further micrometer head, the first probe rotates about the spherical body and thus moves in the Y-direction. When the first lever is pulled, the first probe is pushed back by the first spring and moves in the ?Y-direction. The second probe is moved along the Y-axis by similarly manipulating a further micrometer head. The two probes can be moved along the Z-axis by similarly manipulating other micrometer heads.

Abstract: A method of efficiently inspecting a thin film magnetic head is provided. The method including holding a slider bar having a plurality of the thin film magnetic head elements in a row by an inspecting holding jig made of a nonmagnetic material; loading the slider bar held by the inspecting holding jig to a sampling placing part of a scanning electron microscope; and sequentially executing shape inspection of the plurality of thin film magnetic head elements on the slider bar by the scanning electron microscope.

Abstract: An ion implantation apparatus, system, and method are provided for connecting and disconnecting a workpiece holder from a scan arm. A twist head is provided, wherein an electrostatic chuck is operable to be mounted, wherein one or more rotating and non-rotating members associated with one or more of the twist head and electrostatic chuck have one or more dynamic electrical and fluid rotary connections associated therewith. The electrostatic chuck is further operable to be removed from the twist head without disconnecting the one or more dynamic fluid seals.

Abstract: The invention solves charge nonuniformity of a specimen surface resulting from emission variation of a carbon nanotube electron source and individual difference of emission characteristics. During charge control processing, charge of the specimen surface is measured in real time. As means for solving charge nonuniformity resulting from nonuniformity of electron illumination density, electrons illuminating the specimen and the specimen are moved relatively to average electron illumination density. Moreover, an absorption current flowing into the specimen and the numbers of secondary electrons emitted from the specimen and of backscattered electrons are measured as means for monitoring charge of the specimen surface in real time.

Abstract: A confocal method in which a sample is disposed in the center, a collective lens and a front objective lens are disposed on the incident side, and a back objective lens and a projection lens are disposed symmetrically on the outgoing side is so configured that a spatial filter can be inserted in front of the sample and behind it. As a result, the advantage of the confocal method, which is in the possibility of disposing a spatial filter in front of the sample, is realized and the disadvantages of the conventional transmission phase contrast electron microscope (halo, electron beam loss) are eliminated, thereby providing a phase contrast electron microscope device that enables the establishment of an electron microscopy technology that makes it possible to view of a wide range of materials from material science to life science in a non-dyed state with a high contrast and a high resolution.

Abstract: A lithographic apparatus includes a projection system mounted on a reference frame, which in turn is mounted on a base which supports the apparatus. Vibrations and displacement errors in the base are filtered through two sets of isolation mounts operatively between the base and reference frame and between the reference frame and a projection frame of the projection system and therefore disturbance of the projection system is reduced.

Abstract: An ultra-thin liquid control plate and a combination of a box-like member and the control plate include a plate-like member having at least one view hole. The joint surface combined with a sidewall of the view hole and a surface of the plate-like member is provided with at least one more-hydrophilic section and at least one less-hydrophilic section, wherein the more-hydrophilic section has a height smaller than 50 ?m. While combined with the box-like member, the plate-like member is mounted in the box-like member. The box-like member has at least one through hole running through each of a top side and a bottom side thereof and coaxially aligned with the view hole. After a liquid is placed into the view hole, the more-hydrophilic section adsorbs the liquid to form a liquid layer and the less-hydrophilic section is hydrophobic to adsorb no liquid.

Abstract: An object of the invention is to realize a method and an apparatus for processing and observing a minute sample which can observe a section of a wafer in horizontal to vertical directions with high resolution, high accuracy and high throughput without splitting any wafer which is a sample. In an apparatus of the invention, there are included a focused ion beam optical system and an electron optical system in one vacuum container, and a minute sample containing a desired area of the sample is separated by forming processing with a charged particle beam, and there are included a manipulator for extracting the separated minute sample, and a manipulator controller for driving the manipulator independently of a wafer sample stage.

Abstract: A particle beam system having a beam source for generating a particle beam and a vacuum air bearing. The beam source is mounted to a first side of the vacuum air bearing, with an active side of the vacuum air bearing disposed on an opposing second side of the vacuum air bearing. The active side is adapted to receive and retain a substrate. A beam port is formed completely through the vacuum air bearing from the first side to the second side. Means are provided for moving the substrate across the second side of the vacuum air bearing and positioning the substrate under the beam port. Means are also provided for sealing an interior of the beam source from exposure to atmosphere through the beam port.

Abstract: without substantially touching the surface, having annular rings forming annular orifices, one of the rings forming an air bearing portion and having passages through which a flow of a gas can be established in a first direction, where the flow of the gas is sufficient to create a cushion of air between the puck and the surface, and at least some of the orifices for drawing vacuums through the orifices in a second direction opposite to the first direction against the surface.

Abstract: A semiconductor device fabrication apparatus includes a load lock chamber, a loading assembly in the load lock chamber, and an ion implantation target chamber that is hermetically connected to the load lock chamber. The load lock chamber is configured to store a plurality of wafer plates. Each wafer plate respectively includes at least one semiconductor wafer thereon. The ion implantation target chamber is configured to implant an ion species into a semiconductor wafer on a currently loaded wafer plate. The loading assembly is also configured to load a next one of the plurality of wafer plates from the load lock chamber into the ion implantation target chamber. The loading assembly may be configured to load the next wafer plate from the load lock chamber into the ion implantation target chamber while substantially maintaining a current temperature within the ion implantation target chamber and/or without depressurizing the ion implantation target chamber. Related methods and devices are also discussed.

Abstract: The invention relates to a motorized manipulator for positioning a TEM specimen holder with sub-micron resolution parallel to a y-z plane and rotating the specimen holder in the y-z plane, the manipulator comprising a base (2), and attachment means (30) for attaching the specimen holder to the manipulator, characterized in that the manipulator further comprises at least three nano-actuators (3a, 3b, 3c) mounted on the base, each nano-actuator showing a tip (4a, 4b, 4c), the at least three tips defining the y-z plane, each tip capable of moving with respect to the base in the y-z plane; a platform (5) in contact with the tips of the nano-actuators; and clamping means (6) for pressing the platform against the tips of the nano-actuators; as a result of which the nano-actuators can rotate the platform with respect to the base in the y-z plane and translate the platform parallel to the y-z plane.

Abstract: A method includes receiving an input signal representative of a desired two-dimensional non-uniform dose pattern for a front surface of a workpiece, driving the workpiece relative to an ion beam to distribute the ion beam across the front surface of the workpiece, and controlling at least one parameter of an ion implanter when the ion beam is incident on the front surface of the workpiece to directly create the desired two-dimensional non-uniform dose pattern in one pass of the front surface of workpiece relative to the ion beam. The beam may be a scanned beam or a ribbon beam. An ion implanter is also provided.

Abstract: Sample mounts (10) for mounting microcrystals of biological macromolecules for X-ray crystallography are prepared by using patterned thin polyimide films (12) that have curvature imparted thereto, for example, by being attached to a curved outer surface of a small metal rod (16). The patterned film (12) preferably includes a tip end (24) for holding a crystal. Preferably, a small sample aperture is disposed in the film for reception of the crystal. A second, larger aperture can also be provided that is connected to the sample aperture by a drainage channel, allowing removal of excess liquid and easier manipulation in viscous solutions. The curvature imparted to the film (12) increases the film's rigidity and allows a convenient scoop-like action for retrieving crystals. The polyimide contributes minimally to background and absorption, and can be treated to obtain desired hydrophobicity or hydrophilicity.

Abstract: An electric charged particle beam microscope is provided in which a specimen movement due to a specimen rotation is classified into a repeatable movement and a non-repeatable movement, a model of movement is determined for the repeatable movement, a range of movement is determined for the non-repeatable movement, the repeatable movement is corrected on the basis of the movement model through open-loop and the non-repeatable movement is corrected under a condition set on the basis of the range of movement.

Abstract: An object of the present invention is to provide a suitable method of observing a wafer edge by using an electron microscope. The electron microscope includes a column which can take an image in being tilted, and thus allows a wafer edge to be observed from an oblique direction.

Abstract: A charged particle beam examination equipment for examining and measuring a semiconductor wafer, comprising a wafer exchange portion for exchanging an unexamined wafer and an examiner wafer with each other, which has a first arm longitudinally sliding for reciprocation, a first wafer gripping part provided to the distal end of the first arm, for gripping/releasing the wafer, a second arm longitudinally sliding for reciprocation, and a second wafer gripping part provided to the distal end of the second arm, for gripping/releasing the wafer. The apparatus may shorten the time required for exchange of the wafers so as to enhance the throughput during examination and measurement of the wafers.

Abstract: A sample processing apparatus includes a stage for supporting a sample, a first temperature controller for controlling a temperature of the sample, an ion beam generator for irradiating the sample with an ion beam, and a detector for detecting a signal emitted from the sample in response to the irradiation of the ion beam. Also provided is a probe for obtaining a part of the sample processed by the irradiation of the ion beam and conveying it to a sample table, a second temperature controller for controlling a temperature of the probe, and a third temperature controller for controlling a temperature of the sample table.

Abstract: After a certain direction of a sample piece is allowed to coincide with an intersection line made by two planes of a surface of the sample and a conical side plane obtained by rotating, around a manipulator rotation axis, a line segment which is vertical to the surface of the sample and of which one end is an intersection of the surface of a sample and the manipulator rotation axis, the sample piece is supported by a manipulator and the manipulator rotation axis is operated.

Abstract: In order to provide a full-automatic scanning electron microscope which carries out investigation jobs full-automatically from fine adjustment to reviewing, the scanning electron microscope of the present invention has a function of calculating the accuracy of correction after correction of coordinates and displaying it with vectors 39, a function of automatically determining a searching magnification for automatic object detection from the obtained information after correction of coordinates, and a function of calculating the frequency of occurrence of objects or defects and a time required for measurement from the searching magnification and conditions of measurement.

Abstract: Provided are a scanning probe microscope (SPM) that prevents a distortion of an image caused by alignment errors of scanners and a method of measuring a sample using the same. The scanning probe microscope comprises a probe; a first scanner changing a position of the probe along a straight line; a second scanner changing a position of a sample in a plane; and an adjusting device adjusting a position of the second scanner or the first scanner so that the straight line where the position of the probe is changed using the first scanner is perpendicular to the plane in which the position of the sample is changed using the second scanner.

Abstract: Methods of extracting a TEM sample from a substrate include milling a hole on the sample and inserting a probe into the hole. The sample adheres to the probe, and can be processed on transferred while on the probe. In another embodiment, the sample is freed from a substrate and adheres to a probe by electrostatic attraction. The sample is placed onto a TEM sample holder in a vacuum chamber.

Abstract: The invention relates to a sample manipulation device comprising an observation unit, which is used to observe a sample and to select a target position at which a portion to be removed from the sample is located, and a specimen stage which receives the sample. In a sample manipulation device of this type, there are provided a manipulation tool, which is spatially shiftable relative to the observation unit and comprises a manipulation tip by which portions are removed from the sample, a control unit, which controls the shifting of the manipulation tool, as well as an optical position measurement unit, which is connected to the control unit and is used to determine the actual position of the manipulation tip, so that specific shifting of the manipulation tip to the target position can be carried out.

Abstract: A problem to be resolved by the invention resides in providing a multifunction analyzing apparatus for detecting a shape with high resolution and physical property information capable of not only successively reading a base arrangement from end to end but also specifying a position hybridized by known RNA with regard to a single piece of DNA elongated in one direction on a board. A microscope system of the invention is provided with a fluorescence microscope, a scanning near field microscope and a scanning probe microscope as a detecting system, the microscopes are fixed to a switching mechanism and can be moved to a position at which the various microscopes can observe the same portion of a sample by switching operation of the mechanism. The microscope system of the invention is provided with a function capable of directly detecting a shape and physical property information of one piece of DNA by the scanning probe microscope by multifunction scanning.

Abstract: A scanning probe microscope for measuring a surface profile of a sample by bringing a probe into close proximity to or contact with the surface of the sample and scanning the sample surface includes: a sample stage movable in at least one axis direction; the probe which is brought into close proximity to or contact with the surface of the sample mounted on the sample stage and scans the sample surface; a probe-driving unit for moving the probe three-dimensionally; a probe deflection detector for detecting a deflection of the probe; and an observation optical system which has an objective lens and observes the probe disposed on substantially the optical axis of the objective lens, and the sample. The probe-driving unit is disposed with three sets of paired drive sources arranged essentially with symmetry with respect to the optical axis of the objective lens.

Abstract: Charged particle beam equipment having a rotary mechanism in which shift of the observing/machining position incident to the rotary operation of the equipment having the rotary mechanism can be corrected conveniently with high precision in a plane perpendicular to the optical axis of the optical system of charged particle beam or in a slightly inclining plane. An X-Y shift incident to rotation in a plane is determined from the angular information of a rotary mechanism such as a sample holder, diaphragms or biprisms in the charged particle beam equipment, and then driving or controlling is performed to cancel the X-Y shift.

Abstract: A system for controlling and monitoring a position of a holding element, which is provided to hold a sample to be examined, is disclosed. The system may use a beam device, such as an electron microscope. The system provides for controlling and monitoring a position of a holding element taking into account any errors with respect to irregularities and may include interpolation of possible errors.

Abstract: Disclosed herein is an apparatus and method for partial ion implantation. The apparatus includes a wafer support, an ion beam irradiator capable of generating and irradiating an ion beam entering the wafer, and an ion beam exposure adjustor to adjust exposure of the wafer with respect to the ion beam according to regions of the wafer by setting an exposure opening via combination of ion beam shields for blocking the ion beam with respect to the wafer. The exposure opening enables the wafer to be partially exposed to the ion beam irradiated therethrough. With this apparatus, effective partial ion implantation can be performed to compensate variation of a threshold voltage Vt in a channel of a transistor, thereby providing more uniform characteristics of the transistor.