Alternative boron precursors for BGaAs epitaxy

The organometallic vapor phase epitaxy growth of zinc-blende BxGa1-xAs and BxGa1-x-yInyAs with boron concentrations (x) up to 3-5% has recently been d emonstrated using diborane as a boron precursor. Growth of these alloys usi ng diborane is complicated by many factors, such as parasitic gas-phase rea ctions, highly temperature-dependent boron incorporation, and limited boron incorporation before the onset of structural breakdown. These factors sugg est that diborane may not be the best precursor for the growth of these all oys. We compare the use of alternative boron precursors; trimethylboron (TM B), triethylboron (TEB), and boron trifluoride (BF3), with diborane for the OMVPE growth of these boron containing III-V alloys. We find that TMB and BF3, do not result in significant boron incorporation into GaAs. TEB does r esult in boron incorporation in a manner very similar to diborane. Both dib orane and TEB incorporate more efficiently using triethylgallium (TEG) rath er than trimethylgallium (TMG), making TEG a preferred source of gallium fo r BGaAs epitaxy. Using TEB together with TEG, a higher boron composition (x = 4-7%) has been achieved than has been previously reported, but the compl icating problems observed with diborane still exist.