Optimum built-in barrier height utilizing an extended concept of impedance matching
Schottky-barrier height optimization for high-frequency usage is analytically discussed with an extended concept of impedance matching. The optimum value of 0.3 eV is almost a universal constant under various operating conditions, and agrees well with the previous prediction obtained by large signal simulation and InxGa1-xAs experiments.
Schottky Barrier Diode Optimization for a Low Voltage Power Converter
Optimun barrier height and impurity concentration for a power Schottky diode for maximizing rectifying efficiency are theoretically derived. For a low output voltage, 1.5 ~ 2 V as a DC-DC converter, the barrier height has an optimum value of about 17 times the thermal voltage and the impurity concentration has approximately 1 × 1016 cm-3, for n-type silicon. Schottky diodes with some kinds of barrier metals, such as titanium, hafnium and zirconium were fabricated and applied to a forward mode 2 V 50 A DC-DC converter. Power loss and efficiency were investigated in comparison with control molybdenum diodes. Titanium and hafnium diodes reduced the power loss from 49 W to 37 W for main circuit total loss, which improved the efficiency from 67% to 73%, at package surface temperatures below 60°C. These diodes show better efficiency up to 85°C, compared with molybdenum diodes. Smaller heat sinks or cooling fins can be used because of those low loss characteristics.
Conduction Band Minima ofGa(As1−xPx)
Photoresponse of surface barriers on samples of Ga(As_(1−x_P_x) covering the range 0≤x≤1 has been measured. Thresholds corresponding to both direct and indirect band-to-band excitations within the semiconductor and also photoinjection from the metal have been identified. The threshold of the direct transition varies with composition from 1.37 eV in GaAs to 2.65 eV in GaP. The indirect transition was followed for x≳0.38 and again varied linearly from 2.2 eV in GaP to an extrapolated value in 1.62 eV in GaAs. The energy separation of the two conduction band minima in GaAs is in disagreement with previously reported values.