Technology and properties of a vector hall sensor
Symmetrical four-sided ?12-?m-high pyramids with 30-tilted sides were revealed by the etching of semi-insulating (100) GaAs substrates in 1H3PO4:H2O2:8H2O at ?25C via sacrificial ?001?-oriented Ti/GaAs/AlAs (100/2000/100nm) etching mask patterns. The pyramids, MOCVD overgrown with InGaP/AlGaAs/GaAs heterostructure pyramids, were used as the base for magnetic field vector sensors. Each sensor consisted of three Hall probes defined on the sides of a pyramid. The device processing was realized via AZ5214-E layers deposited conformally over the pyramids by draping from water surface. While the planar reference 55-?m2-sized Hall probes exhibited a sensitivity of ?930VA?1T?1 at 298K, the sensitivity of those on the 30-tilted facets was impossible to determine because they had a resistance of ?100k? at 298K. Further work is necessary to optimize the InGaP/AlGaAs/GaAs heterostructure growth and dopant incorporation on the 30-tilted pyramidal facets.
gaas hall probe vector magnetic field sensor non-planar photolithography omvpe