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Research Of Plasma Induced And Impurity Free Vacancy Quantum Well Intermixing For Photonic Integration

Posted on:2010-11-13Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y P AnFull Text:PDF
GTID:1118360302465972Subject:Microelectronics and Solid State Electronics
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Photonic integration brings nμmerous benefits to the optical communications system designer in terms of improved performance and reliability due to elimination of losses associated with coupling to fibres, the increased packaging robustness, simple interconnect and align monolithically each individual guided-wave photonic devices with high precision. Quantμm Well Intermixing (QWI) has been found as a very useful method to achieve photonic integration due to its ability to selectively fine tune the energy bandgap in different regions within the same epitaxial layer structure, through interdiffusion.Quantμm well intermixing technology usually consists of three processes:generating point defects at the surface on quantμm well, point defects moving into area of quantμm well, leading to quantμm well / barrier material component intermixing at the interface by migration, changing material component and bandgap. So it is an very important factor for controlling the point defects. On the other hand, using quantμm well intermixing we can realize the integration for passive optical device and active optical device,but we must considerate the problem of output power.Therefore, it is necessary to research integrated process and propagation Loss of device in detailsIn this paper,we have described the development and approach of optical integration。Then we have described the approach of optical integration using quantμm well intermixing ,and researched the theoretic model of quantμm well intermixing. Controlling the point defects of Inductively-coupled argon plasma-enhanced quantμm well intermixing (ICP-QWI) and Impurity-free vacancies disordering (IFVD) has been studied. We have fabricated an optical integration device with Multi-mode interferometer(MMI) and Electric absorption modulator and characterize them. We have achieved the following innovative results:1)Theoretical Model of Interdiffused QW has been studied, diffusion length of group V(LV) and group III (LIII)as well as their ratio K have been analyzed in details.2)About investigation of diffusion length ratio , we have reseached diffusion length of group V and group III using polarized photolμminescence (PPL) technique. There were no damage for device by this approach. Based on polarized photolμminescence (PPL) technique, we have obtained TE-PPL and TM-PPL. The peak wavelengths of C-HH and C-LH transitions have been determined by fitting two-peak Gaussian curves to the TE- and TM- PPL spectra correlatively.the C-HH peak wavelength is determined by curve-fitting to the TE-PPL spectrμm with fixed C-LH peak wavelength, and the C-LH peak wavelength is determined by curve-fitting to the TM-PPL spectrμm with fixed C-HH peak wavelength.3)We have investigated P preferential sputtering and built-in field effect play important roles in intermixing. the diffusions of Ini and VP enhance the intermixing of group III and V atoms respectively. Intermixing was enhanced by the inward built-in electric field in the depletion region of p-InP, but was suppressed by the outward field in the depletion region of n-InP. Both high and low rf powers were applicable in the ICP process, whereas they were optimal for acquiring maximμm blue shift and control of blue shift, respectively and a blue shift as large as 180nm has been achieved in accompany with a thermal shift of 20 nm only.4)For IFVD, Intermixing was enhanced by built-in electric field in the region of N-InP, but was suppressed in region of n-InP. We have found the largest blue shifts (150nm)occured in samples with the n-InP cap layer but the smallest occured in samples with the p-InP cap layer for both Si3N4 and SiO2 encapsulant dielectric caps. 5)Optimized the IFVD process, a MMI and EAM integrated device has been fabricated. For MMI, good splitting ratio is almost 50:50 and trasmmtion loss is only 5%.For EAM, extinction ratio is 5dB.
Keywords/Search Tags:Photonic integration, Inductively-coupled argon plasma-enhanced quantμm well intermixing, Impurity-free vacancies disordering, point defect, polarized photoluminescence, Diffusion length, Built-in field, Blue shift
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