From magnetoresistor element to in-plane sensitive Hall device

Abstract

This paper contributes to the development of in-plane sensitive Hall-effect configurations based on a new sensor concept. An original coupling of pairs of identical two-contact (2C) magnetoresistors transduce an in-plane magnetic field, i.e., parallel to the silicon chip surface into a Hall voltages by means of four-contact (4C) and eight-contact (8C) devices. Two different arrangements are accomplished – hybrid realization with a discrete resistor bridge and fully integrated implementation. The pair’s ohmic contacts of the magnetoresistors are cross-coupled and parallel connected. These configurations has linear and odd output signal as a function of the magnetic field and supply current. The quadratic and even magnetoresistance of innovative solutions is completely suppressed, which ensures high measurement accuracy alongside with identification of the magnetic field polarity. The experimental prototypes feature simplified technological fabrication, sensitivity about 100 V/AT, low output temperature drift and high linearity. The lowest detected magnetic induction at current of 3 mA over frequency range 5 Hz ÷ 500 Hz at a signal-to-noise ratio equal to unity is around 10–12 μT. A benchmarking of the characteristics was performed with both new configurations as well as with an in-plane sensitive four-contact Hall element with closed design. It is established that the new arrangements have advantage and confirms the innovativeness of the proposed concept. The complete electrical, temperature and technological matching of proposed Hall devices is very promising for many practical applications.