基于循环退火的Si诱导量子阱混杂研究(特邀)

Research on Si-induced Quantum Well Intermixing Based on Cyclic Annealing(Invited)

腔面光学灾变损伤是制约半导体激光器输出功率以及可靠性的主要因素之一。为制备高功率和高可靠性半导体器件,初步探索了Si杂质诱导量子阱混杂技术,并将其应用于975 nm半导体激光器件的非吸收窗口制备工艺。采用循环退火方式,研究了不同条件下Si杂质诱导量子阱混杂的效果,当退火温度为830℃,退火时间为10 min,循环次数为3次时,达到最大波长蓝移量59 nm。分别在800℃5次10 min和830℃3次10 min退火条件下制备了非吸收窗口。与普通器件相比,制备非吸收窗口的器件阈值电流增大,斜率效率下降,工作电流大于10 A后器件斜率效率降低,电流-工作电流曲线呈现饱和趋势。相较之下,800℃5次10 min条件下对应的器件性能相对较好。工作电流达到15 A后普通器件失效,而制备了非吸收窗口的器件则在电流大于20 A后仍可正常工作,腔面光学灾变损伤阈值提高了33.0%以上。

Catastrophic Optical Mirror Degradation(COMD)is one of the main factors that restrict the output power and reliability of semiconductor lasers.To achieve high power and high reliability and avoid COMD at the same time,Non-absorbing Window(NAW)is often applied to semiconductor laser preparation process,which contains secondary epitaxial growth technology and Quantum Well Intermixing(QWI).For the high cost and high difficulty of secondary epitaxial growth technology,QWI is more widely used.The common methods of QWI include Rapid Thermal Annealing(RTA),Ion Implantation Induced Disordering(IIID),Laser Induced Disordering(LID),Plasma Enhancement Induced Disordering(PID),Impurity Free Vacancy Disordering(IFVD),Impurities Induced Disordering(IID),etc.RTA is easy to achieve,which only needs high temperature annealing,but the repeatability and reliability is low.On the contrary,IIID,LID and PID do well in repeatability and reliability,expensive equipment is needed,however.Besides,IFVD is often conducted in relatively higher temperature.Compared to such methods above,IID technology causes impurity atoms such as Si and Zn diffuse from surface of epitaxial layer into active layer with lower temperature and high repeatability,leading to inter-diffusion of groupⅢatoms between quantum well and barrier,which widen the band gap of quantum well.The mechanism of Si-induced QWI has been controversial,and the SiG+a-VG-apair model is widely used.In the SiG+a-VG-apair model,the diffusion coefficient of isolated Si is small.Si occupies gallium vacancies(VGa)to form SiG+a.The adjacent SiG+aand VGaforms SiG+a-VG-aneutral pair,diffusing by exchanging with surrounding VGaand SiG+a.In this paper,Si-induced QWI under different conditions was explored and applied to the fabrication of 975 nm semiconductor laser devices,using the cyclic annealing method.When the annealing test is carried out under temperature 830℃at a duration of 10 min in 3 cycles,the maximum wavelength blue shift is 59 nm.NAW was fabricated under 800℃at a duration of 10 min in 5 cycles and 830℃at a duration of 10 min in 3 cycles,separately.The results show that threshold current and slope efficiency of the semiconductor lasers with NAW increases compared with ordinary devices.When the operating current is greater than 10 A,the slope efficiency of the devices decrease,and the Power-Current curves indicates a tendency towards saturation.The performance of the devices prepared under 800℃at a duration of 10 min in 5 cycles is relatively better.Ordinary devices fail when the operating current reaches 15 A.Devices with NAW can still work normally after the current is greater than 20 A,and the COMD threshold is increased by more than 33.0%.