Book Description
A new approach for fabricating nonalloyed ohmic contacts to gallium arsenide was developed. The approach uses ultrathin layers of heavily doped germanium or silicon in contact with gallium arsenide to alter the Schottky barrier height(phi B) at the gallium arsenide interface. For n-type gallium arsenide phi B could be varied from about 0.3 to 1.0 eV. The low barriers are useful for tunneling ohmic contacts to n-gallium arsenide while the high barriers should be useful for p-gallium arsenide ohmic contacts and for Field Effect Transistor (FET) gate applications. In some instances it was necessary to interpose a thin nonmetallic electrically conducting barrier between the contact metal and the thin germanium or silicon layer to preserve optimum contact properties. Specific contact resistivity measurements indicated that contact resistivity
