Abstract :
The paper covers the design and performance of improved low magnetic detection devices combining optimized Hall plates and magnetic concentrators. The factors relating to the fabrication of a high gain concentrator are presented, and a Hall effect device compatible with this magnetic structure is then developed. Wide band width, stable operation, shock and vibration, output voltage, power requirements, all relative to low level performance are considered. Performance data from several devices is presented and operational characteristics discussed. The relationships of concentrator length and air gap or Hall plate thickness are utilized to provide magnetic gains of over 100 times that of the ambient magnetic field. Indium Arsenide, Indium Antimonide and other III-IV compound semiconductor devices are shown to be ideally suited for this application due to the combination of high mobility, low resistivity, high purity and temperature characteristics. Exceptional performance is achieved in one sensor designed for operation at -196°C. This sensor exhibits an overall sensitivity of 2500 volts per ampere kilogauss as well as exceptional stability. In conclusion, the feasability of further improvement in sensitivity, weight reduction, size and power requirements is discussed.
