Abstract: A magnetoresistor (MR) and a non-magnetoresistor (NMR) are formed of indium antimonide or other magnetoresistive material in thermal proximity to each other on an integrated circuit substrate (100). Hall effect shorting strips (104) are formed on the magnetoresistor (MR) to make it much more magnetoresistive than the non-magnetoresistor (NMR). A current mirror (80) causes equal constant currents (I2) which do not vary with temperature to flow through the magnetoresistor (MR) and non-magnetoresistor (NMR), such that magnetoresistor and non-magnetoresistor voltages are developed thereacross respectively. The magnetoresistor and non-magnetoresistor voltages vary equally in accordance with temperature. The magnetoresistor voltage also varies in accordance with applied magnetic flux. A comparator (66) subtracts the non-magnetoresistor voltage from the magnetoresistor voltage to produce an output signal (Vout) with the temperature variation canceled, and which thereby varies only in accordance with magnetic flux.

Abstract: An array of Corbino disks are connected in series to provide a high sensitivity magnetoresistor device with a total resistance determined by the number of disks in the array and their geometries. Each Corbino disk has a hub terminal on a layer of magnetoresistor material, and a surrounding conductive shorting ring. The disks are connected in an alternating series connected with alternate inter-disk connections made between the hub terminals of successive disks, and the intermediate inter-disk connections made between the shorting rings of successive disks. Current flow through the array thus alternates between hub terminal-to-shorting ring and shorting ring-to-hub terminal for successive disks. The disks are preferably provided in pairs on mutually isolated islands, with the shorting rings and hub terminals on opposite surfaces on the disks.

Abstract: All of the resistors in a magnetic field sensitive circuit, both magnetoresistors (MRs) and fixed resistors (FRs), are formed simultaneously in a common fabrication process from a common magentoresistive material. An additional structure in the form of Hall shorting strips is applied to selected resistors to rendered them MRs, while the resistors without the additional structure function as FRs. In one circuit the resistors are arranged in pairs in two voltage divider circuits. The high voltage resistor for one circuit and the low voltage resistor from the other circuit are MRs while the remaining resistors are FRs, producing an increased magnetic sensitivity. In another circuit all resistors are MRs and are positioned so that the magentic field at one pair swings in a direction opposite to that of the other pair, further increasing the magnetic sensitivity. Discrepancies stemming from temperature coefficient mismatch and manufacturing variations are substantially reduced.

Abstract: Photodiode testing apparatus having the capability of directly measuring photodiode impedance. An E-beam machine is used for photodiode testing, the beam being selectively directed to different diodes in an array. A varying level of infrared flux is applied to the photodiode, causing the photodiode to develop ac voltage and current signals which are used for the direct measurement of impedance.