1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to fabricating a resistive probe having a self-aligned metal shield, and more particularly, to fabricating a resistive probe having a metal shield whose aperture is self-aligned with a resistive region.
2. Description of the Related Art
As compact products, such as mobile communication terminals and electronic pocket notes, become more popular, the demand for micro integrated nonvolatile recording media increases. However, it is not easy to downsize existing hard disks nor to highly integrate flash memories. Therefore, information storage devices using scanning probe microscopy (SPM) have been studied as an alternative.
Probes are used in various SPM techniques. For example, probes are used for a scanning tunneling microscope (STM) that detects current produced when voltage is applied between a probe and a sample to reproduce information, an atomic force microscope (AFM) that uses an atomic force between a probe and a sample, a magnetic force microscope (MFM) that uses an interaction force between a magnetic field produced by a sample and a magnetized probe, a scanning near-field optical microscope (SNOM) that overcomes a resolution limitation due to the wavelength of visible light, and an electrostatic force microscope (EFM) that uses an electrostatic force between a sample and a probe.
In order to record and reproduce information at high speed and density using such SPM techniques, a surface charge in a small area of several tens of nanometers in diameter should be detected. Also, cantilevers should be in the form of an array to increase recording and reproduction speeds.
FIG. 1 is a cross-sectional view of a cantilever 70 with a resistive tip 50, which is disclosed in International Patent Publication No. WO 03/096409. The resistive tip 50 is formed to be perpendicular to the cantilever 70 and the cantilevers 70 can be fabricated in the form of an array to have a resistive region 56 of several tens of nanometers in diameter.
Referring to FIG. 1, the resistive tip 50 of the semiconductor probe includes a body 58 doped with a first impurity, the resistive region 56 disposed at a peak of the resistive tip 50 and lightly doped with a second impurity, and first and second semiconductor electrode regions 52 and 54 formed on inclined surfaces of the resistive tip 50 with the resistive region 56 therebetween and heavily doped with the second impurity.
However, the related art semiconductor probe with the resistive tip 50 has a disadvantage in that the first and second semiconductor electrode regions 52 and 54 formed on the inclined surfaces of the resistive tip 50 are excessively wet-etched during a process of forming the resistive tip 50, thereby reducing the areas of the heavily doped inclined surfaces. Conductive areas on the inclined surfaces are accordingly reduced, thereby degrading the spatial resolution of the resistive region 56.
The spatial resolution of the semiconductor probe can be improved by forming a metal shield on a portion other than the resistive region 56. However, it is not easy to align a metal shield having an aperture of 100 nm in diameter with the resistive region 56 to expose the resistive region 56.