A multi-finger structure power SiGe HBT device （with an emitter area of about 166μm^2） is fabricated with very simple 2μm double-mesa technology. The DC current gain β is 144.25. The B-C junction breakdown voltage reaches 9V with a collector doping concentration of 1 × 10^17cm^-3 and a collector thickness of 400nm. Though our data are influenced by large additional RF probe pads, the device exhibits a maximum oscillation frequency fmax of 10.1GHz and a cut-off frequency fτ of 1.8GHz at a DC bias point of IC=10mA and VCE = 2.5V.
A micromachined vertical cavity tunable filter with AlGaAs/GaAs distributed Bragg reflector is presented.This filter can be electrostatic tuning over a range of 28nm with an applied voltage of 7V.
A novel bonding method using silicate gel as bonding medium is developed.High reflective SiO 2/Si mirrors deposited on silicon substrates by e-beam deposition are bonded to the active layers at a low temperature of 350℃ without any special treatment on bonding surfaces.The reflectivities of the mirrors can be as high as 99 9%.A Si-based narrow band response InGaAs photodetector is successfully fabricated,with a quantum efficiency of 22 6% at the peak wavelength of 1 54μm,and a full width at half maximum of about 27nm.This method has a great potential for industry processes.
