High Speed Switching Rectifier Diodes

Schottky diode is precious metals (gold, silver, aluminum, platinum, etc.) A is positive, with N type semiconductor B as anode, using the contact surface forming A barrier rectifier features and made of metal - semiconductor devices.Because there are A lot of n-type semiconductor electronic, only very small amounts of free electrons in the precious metals, so the concentration of electrons from high to low concentration of B in A spread., of course, no hole in A metal, and there is no hole diffusion movement from A to B.With electronic continuously from the spread to A, B, B, surface concentration decreases gradually, electrically neutral surface was damaged, then form the barrier, the electric field direction for B to A.But under the electric field effect, also can produce the electrons in A drift motion from A to B, thus weakened the formation due to the motion of the diffusion of the electric field.When establishing a certain width of the space charge region, different electric drift motion of electrons and the concentration diffusion reach the balance of relative movement of electrons, it forms the schottky barrier.
Typical schottky rectifier circuit inside the structure based on n-type semiconductor substrate, in the above form with arsenic dopant of N - epitaxial layer.Anode using molybdenum or aluminum material blocking layer.Using silica (SiO2) to eliminate the electric field at the edge of the area, improve the withstand voltage value of the pipe.N-type substrate have a very small resistance, its doping concentration is 100% higher H - layer.Formed in the substrate below the N + cathode layer, its function is to minimize the contact resistance of the cathode.By adjusting the structure parameters, N type formed between substrate and the anode metal schottky barrier, as shown.When on both ends of schottky barrier and forward bias (anode metal positive, n-type substrate to connect power cathode), narrow schottky barrier layer, its resistance decreases;On the other hand, if on both ends of schottky barrier and reverse bias, schottky barrier layer is wider, its internal resistance.