Zn doping of InP/GaInAsP device structures in metalorganic molecular beam epitaxy using diethylzinc

Diethylzinc was used as a gaseous p-type dopant source for growth of InP/GaInAsP layers in metalorganic molecular beam epitaxy. In InP layers a significant effect of growth temperature on Zn incorporation and on electrical activation has been found. Additionally, data from a variation of the dopant cracker cell temperature suggest that the dopant molecules should not be fully decomposed for an efficient dopant incorporation. A comparison of Hall data with data from secondary ion mass spectrometry (SIMS) reveals that in InP up to 60% of the accepters appear to be electrically active under optimized experimental parameters, in GaInAs the activation is above 90%. The SIMS data show that dopant profiles with steep flanks can be obtained in InP/GaInAsP structures. However, a dopant redistribution occurs, which is more pronounced in InP layers. This effect is correlated with the dopant incorporation behaviour on substitutional and interstitial sites. The dopant incorporation process is discussed in detail, and the implications for growth of InP/GaInAsP device structures are outlined.