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Co-implantation of Group VI Elements and Nitrogen for the Formation of Non-Alloyed Ohmic Contacts for n-type GaAs IB-1609

Wladyslaw Walukiewicz and Kin Man Yu at Berkeley Lab have developed a technique that would facilitate manufacture of energy efficient advanced semiconductor devices. Semiconductor devices made from gallium arsenide materials commonly include one or more electrical contacts through which electric current received via a bonding wire is distributed across the surface of the gallium arsenide material. These contacts are commonly referred to as Ohmic contacts to a semiconductor device. To minimize heat generation and reduce power consumption in the semiconductor device, the electrical resistance of the electrical contact, and the voltage drop across the contact, should be minimized. The Berkeley Lab invention provides a method to fabricate low resistivity non-alloyed ohmic contacts on devices with n-type gallium arsenide surface.This is achieved by the large enhancement of the n-type doping in GaAs by the co-implantation of nitrogen and a group VI donor species (S, Se and Te) in GaAs. The role of the nitrogen is to modify the conduction band structure of GaAs so that high free electron concentration can be attained by the group VI donors. This method can also be extended to any semiconductor (Group III-V) whose doping property can be modified by the introduction of an isovalent element. The invention also provides for a method to fabricate a low resistivity non-alloyed ohmic contact with n-type Group II-VI semiconductor that is co-implanted with oxygen and a Group VII element.
Low resistivity - Minimize heat generation - Reduce power consumption - Simple fabrication process - Reproducible process
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