In-situ monitoring of etch by-products during reactive ion beam etching of GaAs in chlorine/argon

摘要

Mass spectrometry of the plasma effluent during Reactive Ion Beam Etching (RIBE) of gaAs using an Inductively Coupled Plasma (ICP) source and a Cl_2/Ar gas chemistry shows that AsCl_3, AsCl_2 and AsCl are all detected as etch products for As, while GaCl_2 is the main signal detected for the Ga products. The variation in selective ion currents for the various etch products has been examined as a function of chuck temperature (30-100 deg C), percentage Cl_2 in the gas flow, beam current (60-180 mA) and beam voltage (200-800 V). The results are consisten with AsCl_3 and GaCl_3 being the main etch product species under our conditions, with fragmentation being responsible for the observed mass spectra.