Study of Silicon Incorporation in GaAs Movpe Layers Grown With Tertiarybutylarsine

Abstract

AbstractMOVPE growth experiments have been used to evaluate the role of gas phase and surface chemistry in the silicon doping of GaAs films grown using SiH4 and Si2H6 dopant sources and tertiarybutylarsine (t-C4H9AsH2 or TBAs) as the Group V source. The use of TBAs with SiH4 results in a greater Si doping efficiency and weaker dependence on growth temperature than is typically observed with AsH3. Gas phase pyrolysis studies combined with reactor residence time experiments indicate that heterogeneous chemistry is responsible for this enhanced Si doping process. TBAs has much less of an effect on Si incorporation from Si2H6, a doping process controlled by homogeneous Si2H6 chemistry. Increased Si doping from Si2H6 with TBAs can be attributed to contributions from the enhanced doping efficiency of SiH4, a product of Si2H6 decomposition. The influence of TBAs on SiH4 doping chemistry was found to improve the doping uniformity of GaAs films grown in our reactor, from +/-12% for films grown with AsH3to +/-5% for TBAs-based material.