ULTRA-LOW RESISTANCE CONTACTS TO GaAs/AlGaAs QUANTIZED HALL RESISTORS

摘要

Contacts to quantized Hall resistors (QHRs) must meet demanding specifications for contact resistance, reliability, ruggedness, and resistance to degradation. A study of contact materials showed that contacts composed primarily of Indium meet all of these specifications, but experience has shown that contacts of sufficient quality are hard to make reproducibly. The principal factors influencing contact quality are the concentration of electrically active defects in the contact region, and the uniformity of the metal-semiconductor interface. The former can be minimized by the use of high purity materials and careful cleaning. The work reported in this paper has resulted in the development of a technique for reliably producing contacts with high interfacial uniformity and high quality.