1. Field
The following description relates to a vertical Hall sensor, a Hall sensor module and a method for manufacturing the same. With respect to such a sensor, by applying a trench structure inside a substrate, a directional component of a magnetic field parallel to a surface of the substrate is maximized with respect to a current flow to help the sensor detect the magnetic field.
2. Description of Related Art
A vertical Hall sensor is a Hall effect sensor enclosed within a substrate. A Hall effect sensor is a transducer that varies its output voltage in response to a magnetic field. With respect to constructing a vertical Hall sensor, providing higher sensitivity, lower manufacturing costs, availability of an Integrated circuit (IC) and the capability of successfully detecting a magnitude of the magnetic field parallel to a surface of a die are useful aspects of such a sensor.
Such a vertical Hall sensor requires more than five contacts. Specifically, one power input contact for positive power, two left/right sensing contacts, or electrodes, and two ground contacts for negative power are required. In such a structure, a current path formed between the input contact and the ground contacts is easily bent in accordance with the magnitude of the ambient magnetic field. Specifically, the above described vertical Hall sensor is designed to detect and measure the operating current Is that changes according to the ambient magnetic field in order to thereby detect and measure the ambient magnetic field. The detector basically detects changes in current flow resulting from an applied external magnetic field, through measuring a change in voltage received at the sensing contacts.
With reference to a typical vertical Hall sensor, the operating current between the input contact and two ground contacts includes a vertical current component and a horizontal current component. The vertical current component causes the accuracy to be degraded in detecting a direction and a magnitude of the magnetic field, because changes in vertical current flow do not necessarily result in a change in the voltages present at the sensing electrodes.
To address these issues, various methods are proposed to develop a vertical Hall sensor in which a magnitude of a vertical current component is minimized and a magnitude of a horizontal current component is maximized. By doing so, the accuracy of such a vertical Hall sensor is improved.
Other vertical Hall sensors generally have most of the current paths being formed at the surface, or near the surface, of the substrate. This design approach results in reduced sensitivity because of interface charges typically present at the sensor surface, between the semiconductor surface and overlying dielectric films. In an effort to resolve such issues, many methods of additionally forming a depletion region of a certain depth from the surface of the substrate and implementing an additional heat treatment with respect to dopants in order to expand the depletion region are employed. However, such methods result in the increase of costs for manufacturing a vertical Hall sensor that employ these methods.