Microstructure, Stress and Electrical Properties of the Highly Stable W/P+-In0.53Ga0.47 as Ohmic Contacts

ABSTRACTNon-alloyed refractory ohmic contacts to P+-ln0.53 Ga0.47 As layer have been fabricated using sputtered W and rapid thermal processing. These contacts showed excellent thermal stability over the temperature range of 300 to 750°C, with an abrupt and almost unreacted metal-semiconductor interface. The W film biaxial stresses were found to be strongly depended on the Ar pressure during the sputter deposition. At low Ar pressures the film were deposited with compressive stress, and became tensile at pressures higher than 7mTorr with a maximum value of about 8×l09 dyne cm2 as a result of Ar deposition pressure of 28mTorr. The W contacts to Zn doped 1×1019 cm−3 In0.53GA0.47 As film was found to be ohmic already as deposited with a minimum specific resistance of about 7.5×10−6 Ωcm−2, achieved as a result of heating at 600°C for about 30 sec.