Metallic p-type GaAs and InGaAs grown by MOMBE

Heavily carbon-doped p-GaAs layers with a hole concentration of 1.5 × 10 21 −3.4 × 10 18 cm -3 were grown by metalorganic molecular beam epitaxy (MOMBE). The carrier concentration agrees well with the carbon concentration measured by SIMS, which suggests 100% of electrical activation of the incorporated carbon as an acceptor. The p-n diodes with carbon-doped p-GaAs show good rectification. The lattice constant of GaAs decreases with increasing carbon concentration. The carbon-doped InGaAs with a hole concentration of 2.6 × 10 20 cm -3 , lattice-matched with a GaAs substrate, was obtained for the first time. The effective bandgap narrowing in heavily doped GaAs was also studied by photoluminescence. The measured bandgap with a hole concentration of 10 20 cm -3 is about 100 meV lower than that of intrinsic GaAs. Finally, the static and high-frequency characteristics of heterojunction bipolar transistors with carbon-doped p-GaAs were calculated.