Simulations of residual offset of Five-Contact vertical Hall devices with slim waist

Abstract

As an important part of three-dimensional (3D) magnetic sensors, the vertical Hall devices directly determine the overall performance of the sensors. However, the traditional vertical Hall devices (5CVHD) have large offset and low sensitivity due to an inherent electrical asymmetry. In order to solve this problem, the traditional five-contact vertical Hall devices are optimized to obtain the five-contact vertical Hall devices with slim waist (SW-5CVHD) in this paper, and an anti-parallel coupling method which is suitable for the devices is applied. In addition, based on TCAD software, this paper gives a new 3D process simulation model that is more accurate than the traditional 2D model. The 3D simulation results show that the SW-5CVHD have higher sensitivity and lower initial offset compared to the traditional 5CVHD. After applying the anti-parallel coupling method, the novel devices achieve a higher symmetry by double identical SW-5CVHD interconnected into what we call the anti-parallel coupling double SW-5CVHD (APSW-5CVHD). As the structure of APSW-5CVHD is fully symmetrical, which can be better combined with the spinning current technology for offset cancellation. As a simulation result, with a bias voltage of 1 V and after spinning current a mean equivalent residual offset of 60.0µT with a standard deviation of 74.4µT is achieved among 15 samples. Moreover, the Hall voltage sensitivity is approximately 21.7 mV/VT at 1 V bias voltage.