Properties of carbon-doped InGaAs grown by atmospheric pressure metalorganic chemical vapor deposition using CCl 4

Abstract

This paper shows the results of a van der Pauw-Hall analysis of carbon-doped InGaAs epilayers grown by atmospheric pressure metalorganic chemical vapor deposition using CCl 4 gas. Heavily C-doped In x Ga 1 − x As ( x = 0 to 0.52) epilayers were obtained by varying the V III ratio from 1.3 to 32 and at a low growth temperature of 550°C, while keeping the flow rate of CCl 4 constant. For up to an InAs mole fraction of 0.43, a hole concentration of about 1.1 × 10 19 cm −3 was obtained. In the case of as-grown samples, a type conversion from p-type to n-type to n-type occurred at an InAs mole fraction of 0.48. This work also describes the effects of a rapid thermal annealing (RTA) on the electrical properties, particularly on a type conversion of InGaAs. After the RTA process at an annealing temperature of 750°C for 5 s, as-grown In 0.44Ga 0.56As with the p-type of 5.6 × 10 17 cm −3 was converted into the n-type of 3.9 × 10 17 cm −3. This can be attributed to the breaking of the CH or CH x bonds after the RTA process. The broken carbon atoms could enter into arsenic sites or indium (or gallium) sites in the epilayers. With increasing InAs mole fraction, more carbon atoms were supposed to enter into indium sites rather than arsenic sites, due to a lower binding energy of InC than that of AsC.