A method for preparing a silicon epitaxial layer on a heavily doped thin phosphorus substrate for a Schottky device

Abstract

The invention relates to a method for preparing a silicon epitaxial layer on a heavily doped thin phosphorus substrate for a Schottky device, which adopts an atmospheric pressure flat-plate epitaxial furnace. Polish the furnace base; (2) Load phosphorus-doped silicon substrates into the epitaxial furnace, and purge the epitaxial furnace cavity with nitrogen and hydrogen with purity ≥ 99.999% in sequence; (3) Use hydrogen chloride gas to polish the surface of the silicon substrate ; (4) Purging the surface of the silicon substrate with a large flow of hydrogen; (5) Growing the intrinsic epitaxial layer; (6) Purging the reaction chamber of the epitaxial furnace with variable flow; (7) Doping epitaxy layer growth. The beneficial effect is that the thickness non-uniformity of the epitaxial layer is less than 1%, the resistivity non-uniformity is less than 1%, the surface has no defects such as stacking faults, dislocations, slip lines, fog, etc., and the width of the transition zone can be less than 1 um under the best conditions , which fully meets the requirements of the Schottky device on the silicon epitaxial layer, and improves the performance and yield of the Schottky device.

Description

technical field [0001] The invention relates to a preparation technology of a silicon epitaxial layer for a Schottky device, in particular to a preparation method for a silicon epitaxial layer on a heavily doped thin phosphorus substrate for a Schottky device. Background technique [0002] Schottky devices are low-power, high-current, ultra-high-speed semiconductor devices. Key devices such as breakdown voltage and forward voltage drop basically depend on the parameters of the epitaxial layer substrate, especially high-performance silicon Schottky diodes. The quality of the epitaxial layer has higher requirements, such as better uniformity, narrow transition zone, and low defect density. At present, Schottky devices prefer the epitaxial layer on the heavily doped phosphorus substrate, which can greatly reduce the forward voltage drop and reduce the power consumption of the device. bottom (resistivity 0.002~0.004 Ώ cm), due to the higher doping concentration, the substrate i...

AI Technical Summary

Problems solved by technology

But at the same time, due to the difference in the thickness of the substrate, the distribution of the flow field in the epitaxial cavity will inevitably be different, which increases the difficulty of thickness uniformity control

Moreover, substrates with different thicknesses need to experience different thermal stresses during the epitaxial growth process, which greatly increases the difficulty of controlling epitaxial defects.

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