FABRICATION OF GaAs/ AlGaAs QUANTUM WELL LASERS WITH MeV OXYGEN ION IMPLANTATION*

Me V oxygen ion implantation in GaAs/ AlGaAs has been shown to provide a simple and very promising technique for quantum well laser fabrication. A lOμm stripe single quantum well (SQW) graded-index separation confinement heterostructure (GRINSCH) laser made in this way has achieved high performance with high quantum differential efficiency, low threshold current and good electrical isolation characteristics. MeV oxygen ion implantation with optimum thermal annealing produces a deep buried electrical isolation layer in n-type GaAs and reduces optical absorption in GaAs/ AlGaAs quantum well structures. Ion implantation stimulated compositional disordering as well as implanted oxygen-related deep level traps may be considered as important effects for electrical and optical modification of interfaces in GaAs and AlGaAs. INTRODUCTION Ion beam processing of semiconductors with ke V ions is a well-established technique for material surface modification and for electrical device fabrication. However, extending the beam energy to the MeV range in the processing offers the decided advantage of a greater ion range, which results deep implantation with minimum radiation damage at the sample surface. Thus, it allows many unique opportunities for the property modification of interfaces and deeply buried layers, and has high potential for three-dimentional device fabricationl 1l. For 111-V compound semiconductors, MeV ion beam processing has several promising applications since it has capabilities complementary to alternative methods such as thermal diffusion, chemical etching, liquid-phase and molecular-beam epitaxy. In this paper we present one example of an application of MeV ion beam processing in 111-V optoelectrical device fabrication. In semiconductor laser technology, considerable attention is still paid to injection current control and lateral optical confinement in order to gain high efficiency, low threshold current, and high power. In conventional fabrication processes, a complex procedure is commonly involved, in which the injection current is constrained by a Si02 stripe, which is thermally grown on top of the device, and the optical wave is guided by a cavity surrounded on all sides by the lower index AlxGa1 -xAs heterostructures created through chemical etching and subsequent regrowthl2l. one popular laser incorporating such tranverse confinement with the buried heterostructure is presented in figure l(a), taken from reference 2. Ion implantation has also * Support in part by National Science Foundation [DMR86-15641] Mat. Res. Soc. Symp. Proc. Vol. 144. '1989 Materials Research Society