Ultra-low Offset Vertical Hall Sensor in CMOS Technology

An Analytical Theory of Hall-Effect Devices with Three Contacts

“…A vast plurality of topologies was proposed for VHalls, yet one important group of VHalls comprises a single Hall tub with only three contacts on one side and a single mirror symmetry Fig. (2) [15,16]. It can also be viewed as a basic building block for more complex Hall-effect devices.…”

“…These two resistances and the sheet resistance are not independent from each other. From [10] we use (14) and (15) into (5a) and we use (A15) from [5] to get L(4R sh / R H ) = k 1 2 with k 1 = (1 -tan α 1 ) / (1 + tan α 1 ). Again from [10] we plug (14) into (4b) to get R sh (1 / R H + 1 / (2R D )) = K'(k 1 ) / (2K(k 1 )).…”

“…The reason, why we can measure sheet resistance with van der Pauw technique is: the ratio R H / R D is accessible to electrical measurement and it depends only on the layout and not on the sheet resistance. From (6), (14), (15) in [10] and (A15) in [5] we derive the relation (10b) with λ = 2K(k 1 ) / K'(k 1 ). (10b) rises monotonously from 0 to 1 for λ: 0 → ∞.…”

Hall Effect Devices with Three Terminals: Their Magnetic Sensitivity and Offset Cancellation Scheme

“…(3) Another strategy is to use several disjunct Hall tubs and connect them with wires in a ring topology like in Figure 4 [8,9]. This arrangement is perfectly symmetric; however, the price we pay is that the voltage drop in these two tubs, which have the supply terminals, does not contribute to the Hall effect.…”

“…So the measurement indicates that the residual offset of the 5C-VHall is twice the residual offset of the 3C-VHall. At 0.55 V supply the ultralow offset VHall in [9] has 50 Trms offset, yet it is composed of 16 tubs, whereas the 3C-VHall in Figure 14 is only a single tub. A parallel connection of four 3C-VHalls of Figure 14 has the same internal resistance as the ultralow offset VHall in [9] and is expected to have the same offset, namely, 100/sqrt(4) = 50 Trms.…”