A study on maskless selective growth of Mg-doping p-type GaAs using low-energy focused ion beam

Abstract

Maskless selective growth of Mg-doped GaAs films was performed by using a low-energy (30–200 eV) Mg–Ga focused ion beam (FIB) under the ambient of As 4 molecular beam. Under suitable As 4 pressure, all samples showed p-type and the carrier concentrations were around 10 17 cm −3. We achieved very high sticking coefficient of Mg ( k Mg of nearly 10 −1) compared with the result obtained at Molecular beam epitaxy (MBE) growth ( k Mg of nearly 10 −5). A p–n junction was formed on n +-type GaAs substrate by maskless selective growth. The diode showed typical I– V characteristics and the quality factor ( n-value) was approximately 1.75 for the sample grown at 60 eV. These results indicate that this method would be suitable for making maskless selective micro-device fabrication.