Heavily carbon-doped GaAs (1×1018∼1×1020 cm−3) grown by low-pressure metalorganic chemical vapor deposition using triethylgallium and arsine as sources and liquid carbon-tetrachloride (CCl4) as dopant has been investigated. The carrier concentration was verified at various growth temperatures, V/III ratios, and CCl4 flow rates. Dopant concentration first increased from 550 °C and reached a maximum at 570 °C growth temperature (Tg) and then decreased monotonously. Carbon incorporation was strongly enhanced when the V/III ratio was less than 30 at Tg=590 °C or less than 40 at Tg=630 °C. Hole concentration increased and then decreased as CCl4 flow rate increased. Growth rate of layers decreased as growth temperature and flow rate of CCl4 increased. The doping efficiency of epitaxial layers grown on the (100) substrate was higher than that on the 2° off toward <110≳ misoriented substrate. Carbon-doped GaAs films had higher Hall mobility than zinc-doped GaAs films at high doping levels due to less self-compensation. The highest dopant concentration in this system was 2.3×1020 cm−3 at Tg=580 °C and V/III=10.

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An anomalous mobility enhancement and metallic-type conductivity were observed in heavily carbon-doped GaAs grown by low-pressure metalorganic chemical vapor deposition. The 77 K mobility was slightly lower than that of 300 K for hole concentration between 1×1018 and 4×1018 cm−3. However, the 77 K mobility was enhanced from p≳4×1018 cm−3, and the 300 K mobility slowly decreased with increasing hole concentration that ranged from 7×1018 to 3×1019 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.

Heavily Carbon doped GaAs(l×1018−1×1020cm−3 ) grown by low pressure metalorganic chemical vapor deposition(LPMOCVD) using triethylgallium(TEGa), arsine(AsH3) as sources and liquid carbon-tetrachoride(CCI4) as dopant has been investigated. The carrier concentration was verified at various growth temperatures, V/III ratios and CCI4 flow rates. Dopant concentration first increased from 550°C and reached a maxium at 570°C and then decreased monotonously. Carbon incorporation was strongly enhanced when V/III ratio was less than 30 at Tg=590°C or less than 40 at Tg=630°C. Hole concentration increased and then decreased as CCI4 increased. The doping efficiency of epitaxtial layers grown on(100) substrate was higher than that on 2° off toward <110> misoriented substrate. Carbon doped GaAs films had higher Hall mobility than zinc doped GaAs films at high doping level due to less self-compensation. The highest dopant concentration in this system was 2.3×1020cm−3 at Tg=580°C and V/III=10.