Laser annealing method of SiC-based semiconductor

Abstract

The invention relates to a laser annealing method of aSiC-based semiconductor. The method comprises the following steps: relevant parameters of a metal film on a SiC substrate are determined, and the relevant parameters of the metal film at least comprise a metal type and a metal film thickness; determining laser parameters according to related parameters of the metal film, wherein the laser parameters at least comprise power density and pulse width; and according to the determined laser parameters, adopting a semiconductor laser to generate corresponding pulse laser, and performing annealing treatment on the SiC-based semiconductor. The semiconductor laser is adopted to realize ohmic contact laser annealing on the SiC-based semiconductor, can replace a solid laser with relatively high cost, and has a huge advantage in cost; the power density and the pulse width of semiconductor laser are easy to adjust, laser parameters can be adjusted according to working conditions of different metal types and different film thicknesses, and ohmic contact laser annealing is carried out; and the semiconductor laser has lower power density, so that the thicker metal film can be subjected to laser annealing, and a wider process application range is met.

Description

Technical field [0001] The present application relates to the field of laser annealing technologies in the semiconductor industry, and more particularly to a laser annealing method of a SiC-based semiconductor. Background technique [0002] As the semiconductor material used by the power device, the band gap is greater than SiC now gives more and more applications, and SiC has a high thermal conductivity, high-profile electric field, and the like, but due to the high cost, manufacturing process Difficult to limit the widespread use of SiC devices, one of the difficulties of manufacturing is the formation of ohmic contact. [0003] Om contact, when the semiconductor is in contact with the metal, the barrier layer is formed, but when the semiconductor doping concentration is high, the electrons can pass through the barrier to form a low resistance value. Ohm contact is very important to semiconductor devices, forming good ohmic contact facilitates the input and output of the curren...

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Problems solved by technology

[0005] Most of the related technologies use solid-state lasers for this type of annealing, including 355nm, 527nm, and 532nm lasers. These technical solutions require high R&D and maintenance costs for solid-state lasers

In addition, because the pulse width of solid-state lasers is generally short, all at the nanosecond level, and due to the different mechanisms of the pulse width of different lasers, the pulse width of solid-state lasers is generally difficult to adjust; so the pulse instantaneous power density Pi of solid-state lasers is very high ( Generally reach 1 ~ 100MW / cm 2 ), the pulse width PW is short (generally 10-1000ns), which causes the temperature gradient from the metal surface to the metal-SiC interface formed by the solid-state laser to be too steep, so that even if the temperature Ts of the metal surface is close to the melting temperature Tm of the metal (For example, the melting point of Ni is 1726K), the temperature Tc of the metal-SiC interface is still low, and the temperature difference ΔT between Ts and Tc is too large

[0006] The larger the ΔT, the lower the temperature that Tc may reach under the extreme process conditions, and the duration td of the metal-SiC interface above the reaction temperature Tr is very short, which limits the process expansion space and wider application of the equipment scope

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