Extension method of material for low forward voltage drop Schottky diode

Abstract

The invention discloses an extension method for a material used for a lower positive pressure reduction schottky diode. The invention controls and optimizes the temperature rising time of each step by adjusting the program of temperature rising and the careful cooperation of hydrogen flux to lead the impurities of a wafer from an underlay to be expanded outwards during a heat treatment process and finally lead the transition area of a silicon epitaxial wafer to reach the range of 1.2 to 1.3 micron by expelling the air by hydrogen. The resistance rate uniformity in the wafer is less than 3 percent by adopting the method of the invention, thereby leading the transition area of the wafer to be controlled between 1.0 and 1.3 micron and leading the resistance rate uniformity in a furnace to be less than 5 percent; besides, the repetitiveness and the reproducibility of the resistance rate and the thickness between furnaces are good; the repetitiveness in the furnace and the transition area of the wafer is good; the uniformity and the consistency of the positive pressure reduction and negative pressure reduction of the schottky diode manufactured by the material are good.

Description

technical field [0001] The invention relates to an epitaxy method for materials for Schottky diodes, in particular to an epitaxy method for materials for low forward voltage drop Schottky diodes. Background technique [0002] For a diode, its power consumption depends on the diode current If and the forward voltage drop Vf. Since If is predetermined by the application, the only way to reduce the power consumption of the diode is to reduce the forward voltage drop (VF). For Schottky rectifier diodes, the forward voltage drop Vf depends on the metal barrier layer and active area used by the diode. The active area mainly comes from the epitaxial layer of the material used in Schottky diodes. Under ordinary processes, the normal growth transition area is generally greater than 1.3 microns, the uniformity of resistivity in the chip is greater than 7%, and the uniformity of resistivity in the furnace is greater than 10%. , and the repeatability and reproducibility between furnace...

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Problems solved by technology

The active area mainly comes from the epitaxial layer of the material used in Schottky diodes. Under ordinary processes, the normal growth transition area is generally greater than 1.3 microns, the uniformity of resistivity in the chip is greater than 7%, and the uniformity of resistivity in the furnace is greater than 10%. , and the repeatability and reproducibility between furnaces are poor. Using this material to manufacture Schottky diodes, when the reverse breakdown voltage meets the requirements, because the transition zone is longer, the corresponding epitaxial effective thickness is reduced, so more Large total epitaxial thickness, resulting in excessive forward voltage drop

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