A High-Sensitivity and Low-Offset Cross-Like X-Hall Device Suitable for Broadband Magnetic Sensors Fabricated in 180-nm BCD Technology

This article proposes a novel cross-like X-Hall device with a buried layer demonstrated on 180-nm standard bipolar-CMOS-DMOS (BCD) technology. The device’s active area with a cross shape is realized by a lowly doped n-type drift (NDRF) layer to enhance magnetic sensitivity. Four big contacts are distributed in four fingers for dc biasing, while four small inner contacts through diagonal shorting are located at the edges of the central region to sense Hall voltage. In such a configuration, the offset from the process gradient can be significantly reduced through a dc bias method; thus, the spinning-current offset cancellation circuitry can be removed to expand the bandwidth of sensors. The measurement results reveal that compared with the conventional cross-like Hall devices, the average offset of the proposed X-Hall device is dramatically down to
$-$
14.5
$\mu $
V at a bias of 100
$\mu $
A, with a standard deviation of 150
$\mu $
V over 45 samples. In addition, a high current-related sensitivity of
$>$
310 V/AT and low 1/f noise are also achieved. This Hall device based on the static offset compensation approach provides another low-cost solution to implement broadband magnetic sensors whose bandwidth is limited by spinning-current circuits.