Technology and properties of a vector hall sensor

Symmetrical four-sided 12-mm-high pyramids with 301-tilted sides were revealed by the etching of semi-insulating (1 0 0) GaAs substrates in 1H3PO4: H2O2:8H2O at 25 1C via sacrificial /0 0 1S-oriented Ti/GaAs/AlAs (100/2000/100 nm) 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 5 5-mm-sized Hall probes exhibited a sensitivity of 930VA T 1 at 298K, the sensitivity of those on the 301-tilted facets was impossible to determine because they had a resistance of 100 kO at 298K. Further work is necessary to optimize the InGaP/AlGaAs/GaAs heterostructure growth and dopant incorporation on the 301-tilted pyramidal facets. r 2006 Elsevier Ltd. All rights reserved.