Method for preparing beta-FeSi2 semiconductor film by femtosecond pulsed laser

Abstract

The invention provides a method for preparing belta-FeSi2 semiconductor film by flysecond pulse laser, vacuumizing pulse-laser film depositing device to an air pressure of 10<-5> to 10<-3>, using FeSi2 alloy as target material, placing the target material and a substrate in the pulse-laser film depositing device, where the target material and the substrate, mutually parallel, are 20-50mm apart from each other, heating the substrate to 20 DEG C to 700 DEG C and then keeping warm, irradiating the target material by laser beam with a peak power density of 10<12> to 10<15> W / sq cm<2>, which makes the ejective plasma is deposited on the substrate and epitaxially grows along the crystal face of the substrate to form the film. The invention is suitable for different substrates to synthesize a large-area, uniform, monophasic beta- FeSi2 semiconductor film at lower temperature in a short time, and the prepared film is provided with better light emitting and photovoltaic properties, which solves the technical difficulty in being a high quality beta-FeSi2 film needed by infrared light emitting diode and solar battery.

Description

technical field [0001] The invention relates to a method for preparing a semiconductor thin film, in particular to a method for depositing a thin film with a pulsed laser. Background technique [0002] β-FeSi 2 The preparation methods of semiconductor thin films are usually as follows [0003] (1) Ion implantation (IBS) [0004] Through the silicon substrate, such as the energy is 400keV ~ 2MeV, the dose is 10 17 ~10 19 cm -2 Fe + , and then annealed at a certain temperature to form β-FeSi 2 The buried layer, due to the heating effect during ion implantation, can directly synthesize α-phase and γ-phase FeSi 2 . Disadvantages: It is difficult to obtain large-area β-FeSi 2 Thin film, long film forming time. [0005] (2) Molecular Beam Epitaxy (MBE) [0006] First deposit 0.1-0.2nm of pure iron on the substrate, then evaporate a certain amount of Fe and Si on the substrate according to a certain chemical ratio, keep the substrate at room temperature or heat it to 50-...

AI Technical Summary

Problems solved by technology

Disadvantages: It is difficult to obtain large-area β-FeSi 2 Thin film, long film forming time

Disadvantages: The quality of the film is still not good enough, a high vacuum environment is required, and the growth rate is slow

The disadvantage is that the solid phase reaction only occurs at the interface, and it is difficult to obtain single-phase β-FeSi 2 film, it is difficult to obtain a thicker film, the thickness of the film prepared by solid phase epitaxy is only a few nanometers; the annealing temperature is high (800-900 ° C); the morphology of the film is poor

[0010] The disadvantage of traditional pulsed laser deposition (PLD) is that it uses nanosecond (10 -9 seconds), the energy density is not high enough, the deposition process is still dominated by thermal action, a large number of small droplets are mixed in the deposit, the uniformity of the film is poor, and it is difficult to synthesize a uniform single-phase β-FeSi 2 membrane