Defect studies in low-temperature-grown GaAs

Technical Report · Sun Nov 01 00:00:00 EST 1992

DOI:https://doi.org/10.2172/6891058· OSTI ID:6891058

Bliss, D E

High content of excess As is incorporated in GaAs grown by low-temperature molecular-beam-epitaxy (LTMBE). The excess As exists primarily as As antisite defects AsGa and a lesser extent of gallium vacancies V[sub Ga]. The neutral AsGa-related defects were measured by infrared absorption at 1[mu]m. Gallium vacancies, V[sub Ga], was investigated by slow positron annihilation. Dependence of defect contents on doping was studied by Si and Be dopants. No free carriers are generated by n-type or p-type doping up to 10[sup 19] cm[sup [minus]3] Si or Be. Raman data indicate Be occupies Ga substitutional sites but Si atom is not substitutional. Si induces more As[sub Ga] in the layer. As As[sub Ga] increases, photoquenchable As[sub Ga] decreases. Fraction of photoquenchable defects correlates to defects within 3 nearest neighbor separations disrupting the metastability. Annealing reduces neutral As[sub Ga] content around 500C, similar to irradiation damaged and plastically deformed Ga[sub As], as opposed to bulk grown GaAs in which As[sub Ga]-related defects are stable up to 1100C. The lower temperature defect removal is due to V[sub Ga] enhanced diffusion of As[sub Ga] to As precipitates. The supersaturated V[sub GA] and also decreases during annealing. Annealing kinetics for As[sub Ga]-related defects gives 2.0 [plus minus] 0.3 eV and 1.5 [plus minus] 0.3 eV migration enthalpies for the As[sub Ga] and V[sub Ga]. This represents the difference between Ga and As atoms hopping into the vacancy. The non-photoquenchable As[sub Ga]-related defects anneal with an activation energy of 1.1 [plus minus] 0.3eV. Be acceptors can be activated by 800C annealing. Temperature difference between defect annealing and Be activation formation of As[sub Ga]-Be[sub Ga] pairs. Si donors can only be partially activated.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6891058
• Report Number(s): LBL-33378; ON: DE93010405
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
GALLIUM ARSENIDES
CRYSTAL DEFECTS
MOLECULAR BEAM EPITAXY
ANNEALING
BERYLLIUM ADDITIONS
DOPED MATERIALS
POSITRONS
SILICON ADDITIONS
ALLOYS
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
ARSENIC COMPOUNDS
ARSENIDES
BERYLLIUM ALLOYS
CRYSTAL STRUCTURE
ELEMENTARY PARTICLES
EPITAXY
FERMIONS
GALLIUM COMPOUNDS
HEAT TREATMENTS
LEPTONS
MATERIALS
MATTER
PNICTIDES
SILICON ALLOYS
360602* - Other Materials- Structure & Phase Studies