Publication
The Hall Effect sensors are one of the most commonly used sensing technologies today. They are employed in many applications for direct magnetic field sensing and serve a multitude of low power applications within automotive and industrial electronics as current sensors, for contactless switching, position detection and in electronic compasses. In order to select Hall cells with high performance, good models that would accurately predict their characteristic parameters are undoubtedly necessary. Firstly, by setting up the actual research framework and giving details about the basic considerations regarding Hall Effect devices, the thesis domain is presented. A brief overview of the state-of-the-art in Hall Effect sensors development and applications on the market is included with emphasis on the offset levels achieved. The Hall voltage theoretical background and its rapid evaluation were provided. For six different types of Hall plates, three-dimensional representations were obtained for the inverse of the geometrical correction factor G. Various formulae for Hall mobility evaluation were provided, with a discussion on the relative error obtained in its calculation. Focusing on the analysis at device level, an attentive investigation of the geometrical correction factor as well as its maximization was proposed. In order to obtain maximum sensitivity for Hall cells integrated in the same process, a geometry that would provide a high geometrical correction factor it is advised to be chosen. The close connection between the general aspects and their associated details, regarding the twelve (designed and integrated) Hall cells, was presented. In premiere, three of them have been designed and proposed by the author. The reason behind the specific Hall cells geometries is announced and some designed layouts are given. To test the integrated cells, both an AC and DC automated measurements setup was used. This allows reliable and fast obtention of the desired experimental results. The Hall cells were tested for their input voltage-current characteristics at room temperature, resistance, resistance variation with the temperature, Hall voltage, dissipated power, etc. The absolute sensitivity versus the biasing current was also measured for all the integrated cells. The offset measurements results were just briefly presented, as there is another chapter entirely devoted to its detailed assessment. Parameters extraction was performed on specific tested Hall cells and the Hall cells linearity was also analyzed. A complex physical computing code, for predicting and assessing Hall cells performance with the aid of three dimensional simulations was developed and perfected. The influence of shape, dimensions, n-well concentration, contacts dimension and positioning with respect to the active region on the sensors performance were all aspects covered within this work. To this purpose, different constitutional devices including cross-like cells such as such as basi