Current-related sensitivity optimization of CMOS five-contact vertical Hall sensor

Abstract

Given the increasing demand for three-dimensional (3D) Hall effect sensors, vertical Hall sensors (VHSs), an indispensable part of 3D Hall sensor with low performance, have been increasingly investigated. Previous works on the original VHS named five-contact vertical Hall sensor (5CVHS) have focused on performance improvement. However, the current-related sensitivity of 5CVHS and its influencing factors have been rarely comprehensively investigated. The aim of this paper is to study the influence of the size, structure and technology of 5CVHS on current-related sensitivity so that an optimal solution can be achieved. Besides, the research process and analysis methodology in this study provide an efficient simulation method to substitute tap-outs in iterating the structures of VHS. Thus, this method can reduce the development cycle and deliver real cost savings. Finite element method simulation is used to determine the outstanding current-related sensitivity obtained by optimizing the length, width, and locations of contacts in standard GLOBALFOUNDRIES 0.18 μm BCDlite™ technology. In order to further improve the sensitivity, a covering P-type region is introduced to reduce short-circuit effect by analogy with the cross-like horizontal Hall device. Moreover, the influences of depths of active and P-type regions are studied to obtain optimal sensitivity. Finally, the optimized size, structure, and technology parameters are obtained. Results may serve as reference to the design of the 5CVHS layout.