Mesoskopische Bauelemente. Heterobipolartransistoren fuer hohe Leistungen und Arbeitsfrequenzen Schlussbericht

Bipolar transistors based on III-V-heterostructures are highly attractive for applications as microwave components for high output power, high power-added-efficiency (PAE), high linearity and low phase noise. The goal of this project was the generation of the physical and technological basis for AlGaAs/GaAs- and GaInP/GaAs-HBT. Using the companie's 3''-line for GaAs production and development, different material systems were investigated and compared. MOVPE is the technology selected to fabricate HBT. Differently from MBE it allows the growth of Carbon-doped base-layers. We succeded in fabricating layers with very good uniformities of 2% concerning layer thickness, 0.2% in Al-concentration and 10% in all doping levels. Carbon turned out to be a very stable p-dopand. Incorporation levels up to 10"2"0 cm"-"3 were reached in the base. That is why abrupt emitter-base-transitions were successfully reached. The epilayers developed in the frame of the project fully satisfied the HBT requirements. Comparing different material systems, AlGaAs/GaAs turned out to be of superior stability. With GaInP/GaAs higher peak current gain and higher transit frequencies were achieved. However, it revealed significant disadvantages concerning the stability of I-V curves of the transistors for current densities #>=#10"4Acm"-"2, which is the regime of operation of power devices. Using HBT power cells, very good rf data were achieved: a 0,5 W power cell in the typical regime of operation of mobile communication devices (2 GHz and V_c_e=3V) showed an outstanding gain of 28 dB and an excellent PAE of 74%. This is a very good starting position for mobile communication applications. At 10 GHz still 16 dB and 56% were achieved. (orig.)SIGLEAvailable from TIB Hannover: F97B1279+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman