Parallel-Field Silicon Hall Effect Microsensors With Minimal Design Complexity

Abstract

A new class of Hall microsensors with minimal design complexity was suggested and experimentally tested. The devices consisting in -Si substrate and three + -strip contacts only are sensitive to a magnetic field parallel to the chip surface. Using a reference voltage generating with a specific bridge circuitry, the linear Hall voltage is extracted and the quadratic geometrical magnetoresistance is fully compensated. The internal noise of the design with a Hall contact located outside the sensor active region is at least ten times smaller than those of the three-contact element with an inside placed output electrode. This leads to enhanced resolution reaching min 35 T. A three-terminal multisensors generating simultaneously and independently strongly asymmetric voltage to the magnetic field direction and a Hall signal were devised too. The devices performance proved undoubtedly that new three-contact sensors could compete with the other wellknown vertical Hall elements.

In-Plane Sensitive Magnetoresistors as a Hall Device

“…As a result of the uniformity of the two substrates, as well as of contacts C1 …C4, the two currents IC1,2 and-I C4,3 are equal in magnitude and opposite in sign. If, as a result of technological imperfections, mechanical strain and stress during chip capsulation, temperature gradients and the like [4][5][6], at output VH(B) of the device, at field B = 0, offset VH(B = 0) ≠ 0 appears, notwithstanding that load resistors R1 and R2 are equal, R1 = R2. Varying the value of the low ohmic trimmer r, full compensation of the negative offset at differential output is achieved, VH(B = 0) = 0.…”

“…The well-known 4C in-plane sensitive Hall devices (HD) are widely used in numerous configurations as universal sensors for practical application and last, but not least-to compensate the main disadvantage in differential output transducers-the offset, frequently through dynamic cancellation techniques. In these architectures, one outer and one inner contact are the supply and the other two contacts are the output [1][2][3][4][5][6][7][8][9]. By switching the input and output electrodes of the Hall plate and summing-up algebraically the two obtained voltages, the offset can be significantly decreased [5,7,8].…”

Angular position device with 2D low-noise Hall microsensor

“…A three-contact version of this microsensor is presented in Fig. 1 [12]. These Hall elements strongly minimize one essential problem, related to the CMOS technologythe existence of a surface conductive n-layer of the silicon substrate.…”

“…If the parallel-field Hall device is deep enough, by using four separate sensing contacts only, H 1 -H 2 and H 3 -H 4 , located at the top side of the silicon chip, where one of the terminal pairs is located in the zone of the inside supply contacts [6,9,16], and the other terminal pair is located in the zone outside the supply electrodes [6,9,13], it is possible to achieve maximum sensitivity [15]. So far, in parallel-field Hall microsensors, the Hall voltage has been measured experimentally by two contacts, H 1 and H 2 , and in the elements with minimal design complexity -by one contact H [6,9,11,12,16].…”

“…Notwithstanding the achieved good results, the relatively high level of internal 1/f noise is not sufficiently well resolved in this 2D vector microsensor. On the other hand, the application of bipolar silicon 2D magnetotransistors encounters certain problems, related to the large channel offsets and temperature drift [8,11,12].…”