Incorporation of Si in MOCVD GaAs Epilayers from the Trimethylgallium Source

摘要

The incorporation behavior of Si impurity present in trimethylgallium in the form of methylchlo- rosilanes was studied in GaAs epitaxial layers grown form trimethylgallium and arsine sources by metalorganic chemical vapor deposition. The fraction of Si atoms incorporated in the GaAs layer was demonstrated to increase with increasing number of Cl atoms per methylchlorosilane molecule. Silicon tetrachloride exhibited the strongest contaminating effect. The maximum SiCl_4 content of trimethylgallium above which GaAs layers with a residual carrier concentration below 10~14 cm~-3 cannot be prepared was estimated as 5 × 10-8 mol/100.