Fabrication and high temperature characteristics of ion-implanted GaAs bipolar transistors and ring-oscillators

Ion implantation techniques that permit the reproducible fabrication of bipolar GaAs integrated circuits are studied. A 15 stage ring oscillator and discrete transistor were characterized between 25 and 400 C. The current gain of the transistor was found to increase slightly with temperature. The diode leakage currents increase with an activation energy of approximately 1 eV and dominate the transistor leakage current 1 sub CEO above 200 C. Present devices fail catastrophically at about 400 C because of Au-metallization

3dB directional couplers on image dielectric waveguides of 80–110 GHz frequency band

The effective dielectric permittivity method is applied, generalized and modified to determine image guide dielectric rods configurations for directional couplers with maximal bandwidth in 3–mm wavelength. Problem of optimization of directional coupling, splitting and summing signals in image guide directional couplers with distributed coupling in frequency range of 80–110 GHz has been solved using CST Microwave Studio code. Results of optimization have been experimentally confirmed

Outdiffusion of Be during rapid thermal annealing of high‐dose Be‐implanted GaAs

The outdiffusion of Be implanted into GaAs has been found to be identical after capless or capped (Si3N4 or Si02 ) rapid thermal annealing (RTA) at 900-1000 ºC and to depend on the Be dose and its proximity to the surface. The outdiffusion is more pronounced when the Be implant is shallow (< 0.1 p,m) andlor the Be + dose is high (> 1 X 1015 cm-²). It is demonstrated that the Be outdiffusion is driven by the presence of a highly damaged surface layer. Auger results suggest the formation of a BeOx compound at the surface of a high.dose (1 X 1016 cm-²) Be-implanted sample that underwent capless RTA at 1000 ºC/1 s. It appears that BeOx formation occurs when the outdiffused Be interacts with the native Gal As oxides during annealing. AU the Be remaining in the GaAs after a > 900 ºC/2s RTA is electrically active