No-alloy ohmic contact to heavily carbon-doped GaAs

The doping behavior of carbon doped GaAs materials grown by low pressure MOVPE has been studied. Heavily carbon-doped GaAs layers with hole concentration in the range of 1.5/spl times/10/sup 19/ cm/sup -3/ to 1.9/spl times/10/sup 20/ cm/sup -3/ were obtained. Two different metallization schemes, Ti/Au and Au/Zn/Au, were deposited onto these heavily carbon-doped GaAs layers respectively. The contact resistance before and after alloying was measured using the transmission line method. The relation between hole concentration in GaAs layers and ohmic contact resistance has been obtained. The influence of the alloy process on contact resistance has also been studied. A specific contact resistivity lower than 10/sup -6//spl Omega//spl middot/cm has been achieved in GaAs/TiAu no-alloying structures.