ANOMALOUS MOBILITY ENHANCEMENT IN HEAVILY CARBON-DOPED GAAS

An anomalous mobility enhancement and metallic-type conductivity were observed in heavily carbon-doped GaAs grown by low-pressure metalorgan ic chemical vapor deposition. The 77 K mobility was slightly lower tha n that of 300 K for hole concentration between 1 x 10(18) and 4 x 10(1 8) cm-3. However, the 77 K mobility was enhanced from p > 4 X 10(18) c m-3, and the 300 K mobility slowly decreased with increasing hole conc entration that ranged from 7 X 10(18) to 3 X 10(19) cm -3. As a result , the 77 K mobility was around 50%-60% greater than the 300 K mobility due to the metallic-type conductivity.