Study On GaAs Surface Passivation And Its Application In Facet Passivation Of 1.06 ?m High Power Semiconductor Lasers

The high-power semiconductor lasers are widely used in laser link communication,machining,medical and military fields due to the advantages of compact structure,low price,long service life,and high-speed modulation.In the field of laser link communications field,the 1.06 ?m high-power semiconductor lasers can not only be used directly as communication light sources,but also can be used as seed light sources to develop various compact,reliable,high-power,high-beam-quality solid-state lasers and fiber lasers.However,under high current operation of 1.06 ?m high-power semiconductor laser,due to the high surface state density of the cavity surface of the laser,resulting in the increase of the non-radiative recombination of carriers,causes the light absorption of the cavity surface and the temperature is increased.Eventually,it causes device catastrophic optical mirror damage(COD).Therefore,in the process of preparing 1.06 ?m high-power semiconductor laser,the cavity surface needs to be passivated to reduce the surface state density,and improve the output power and reliability of the laser.This article starts with increasing the COD threshold of semiconductor lasers,analyzes the causes and suppression methods of COD,and researches the effects of optical and electrical characteristics of Ga As surface by wet passivation,plasma dry passivation,and plating passivation film.The passivation of ODT solution,hydrazine solution,SF6 plasma and Zn O/SF6 passivation film were applied in the 1.06 ?m high-power semiconductor laser cavity surface treatment technology to explore the COD power and reliability of semiconductor laser.The main research contents of this paper are as follows:1.The output characteristics of quantum well semiconductor lasers were briefly introduced,the mechanism of COD affecting the output characteristics was analyzed,and the influence of COD on the reliability and stability of the laser was researched.The main reasons for the generation of COD,the method for increasing the threshold of COD,the principle of plasma processing technology and the passivation of the cavity surface of semiconductor laser by plasma were introduced.2.The wet sulfur(S)passivation and wet nitrogen(N)passivation on Ga As surface were researched.The Ga As surface was passivated by ODT solution and hydrazine solution,and the solution parameters of the two passivation techniques were optimized.The experiments show that the oxides on the Ga As surface can be removed by the two kind of wet passivation technologies,and the uniform and flat ODT self-assembly layers(SAMs)and Ga N passivation films were formed on the surface.However,the stability test shows that the photoluminescence(PL)stability of Ga As surface after passivation of hydrazine solution is stronger than ODT solution,indicating that the passivation effect of hydrazine solution is better than ODT solution.3.The passivation of N plasma and SF6 plasma on Ga As surface was researched.TheN plasma and SF6 plasma were introduced by glow discharge to passivate the Ga As surface,and the process parameters of the two kind of plasma passivation technologies were optimized.The experiments show that the Ga As surface can be effectively passivated by the two kind of technologies.However,the time for SF6 plasma passivate Ga As surface is short,and the improvement of PL is obvious.Compared to untreated,the PL is enhanced by158%.In addition,the stability of Ga F3 passivation film formed by SF6 plasma passivation is better than Ga N passivation film formed by N plasma passivation.4.The technology of Zn O passivation film on Ga As surface was researched.The Zn O film was sputtered on Ga As surface by magnetron sputtering.The oxygen vacancies(oxygen dangling bonds)and zinc vacancies(zinc dangling bonds)in Zn O thin film were treated by SF6 plasma.The PL of the luminescence peak of Zn O thin film was enhanced by120% after SF6 plasma passivation.Comparing the passivation effect of Ga As surface passivated by Zn O film before and after SF6 plasma treatment,it was concluded that the PL intensity of Ga As surface passivated by Zn O film after SF6 plasma treatment is stronger than untreated Zn O film.Furthermore,due to the reduction of defects in Zn O films,SF6 plasma treated Zn O film has better PL stability.5.The fabrication technology and cavity surface processing technology of 1.06 ?m high-power semiconductor laser was researched.The wet passivation after optimizing process conditions(ODT and hydrazine solution),dry passivation(SF6 plasma),and plated passivation film(Zn O/SF6)were applied to laser cavity surface treatment,and Al2O3 antireflection coating was plated on the front cavity surface,(Ta2O5/Si O2)^7high-reflection coating was plated on the back cavity surface.After different passivation treatments,it can be concluded that the COD power of 1.06 ?m semiconductor laser after Zn O/SF6 film passivation is the highest.It reaches 6.3 W,which is 79% higher than unpassivated,the passivation effect is the best.