Ferdinand-Braun-Institut für Höchstfrequenztechnik Berlin, Rudower Chaussee 5, D-12489, Berlin, Germany
Abstract:
Carbon doping of GaAs with carbon tetrabromide (CBr4) in low pressure MOVPE has been investigated and applied to the fabrication of GaInP/GaAs HBTs. Especially the hydrogen incorporation and the associated acceptor passivation has been studied. The hydrogen found in single GaAs:C layers is predominantly incorporated during cooling the sample under AsH3 after growth, n-Type capping layers can block this H indiffusion and GaAs:C base layers in HBTs show much lower H concentrations than GaAs:C single layers without a cap. A further reduction of acceptor passivation is possible by optimization of the growth procedure. First HBTs processed from layers with a base that was doped using CBr4 show promising DC and HF performance (β = 45,
for 2 × 20 μm2 devices).