CARBON INCORPORATION IN INP GROWN BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION AND APPLICATION TO INP/INGAAS HETEROJUNCTION BIPOLAR-TRANSISTORS

The incorporation of residual carbon has been studied for InP grown at low temperatures using TMIn and PH3 by low-pressure metalorganic chemical vapor deposition. n-type conduction is observed with electron concentrations as high as 1 X 10(18) cm-3, and the electrical activation efficiency is 5%-15%. Carbon incorporation is found to be highly dependent on substrate temperature, suggesting that the rate-limiting step is desorption of CH(y) (0 less-than-or-equal-to y less-than-or-equal-to 3) from the surface during growth. Hydrogen is also incorporated in the layers during growth. The electron mobilities are lower for C-doped InP than for Si-doped InP. InP/InGaAs heterojunction bipolar transistors with C as the p-type base dopant and either Si or C as the n-type emitter dopant have been fabricated and compared. Devices with a carbon-doped base and emitter showed degraded performance, likely as a result of deep levels incorporated during growth of the emitter.