Doping profiles for indium antimonide magnetoresistors

• Published in: Sensors and actuators. A. Physical. Vol. 69; no. 1; pp. 39 - 45
• Main Authors: Partin, D.L., Heremans, J., Thrush, C.M.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 30-06-1998; Elsevier Science
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Contact resistance, contact potential; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in interface structures; Exact sciences and technology; General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Magnetic sensors; Ohmic contacts; Physics; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; Tunneling; Magnetic sensors; Tunneling; Ohmic contacts; Thin films; Indium antimonides; Tunnel effect; Doping profiles; Experimental study; Impedance; Magnetoresistance
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/S0924-4247(97)01746-9

Indium antimonide is of interest for magnetoresistors in position- and speed-sensing applications. These sensors are fabricated as thin-film elements in order to increase the device impedance. The InSb is normally doped n-type to stabilize the electron density and hence the impedance with respect to temperature changes. This involves tradeoffs, since ionized donors also scatter electrons, reducing their mobility and hence reducing the device sensitivity to a magnetic field. Therefore, optimizing the sensitivity of these devices involves optimizing the doping of the InSb. This optimization involves three steps. The InSb is undoped for the first 10–20% of the film, forming a buffer from the latticemismatched substrate. The middle, active, layer of the film has a doping gradient. Finally, a thin contact layer is more heavily doped to reduce parasitic contact resistance.