| dc.identifier.uri | http://hdl.handle.net/11401/76356 | |
| dc.description.sponsorship | This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree. | en_US |
| dc.format | Monograph | |
| dc.format.medium | Electronic Resource | en_US |
| dc.language.iso | en_US | |
| dc.publisher | The Graduate School, Stony Brook University: Stony Brook, NY. | |
| dc.type | Thesis | |
| dcterms.abstract | Boron phosphide (BP), a light III-V indirect semiconductor compound with medium band gap of 2.0 eV, has emerged as a promising material with its applications in solid-state neutron technology and semiconductor devices in extreme conditions. Since bulk BP is unavailable, heteroepitaxial film growth is being attempted on various substrates including silicon, silicon carbide (4H, 6H, 3C polytypes), AlN and sapphire of different orientations to determine the best substrate for growing high quality thin films. By investigating the defects (e.g. twins and grain boundaries, threading dislocations, stacking faults, inclusions) present in the BP epilayer using synchrotron white beam X-ray topography (SWBXT), high resolution X-ray diffraction (HRXRD), high resolution transmission electron microscopy (HRTEM) as well as other characterization techniques, the aim of this study is to gain insight on defect nucleation mechanisms, and develop strategies from the control of growth parameters (temperature, flux rate, reaction time, P/B ration) and the nature of substrate (Si or SiC, polytype of SiC, off-cut angle and direction) to achieve higher single crystalline quality for fabrication of neutron detectors. Detailed studies are listed below. 1) Defect studies of CVD grown BP epilayer on c-plane SiC substrates. BP heteroepitaxial layers were grown by chemical vapor deposition (CVD) technique on 3C-SiC, 4H-SiC, and 6H-SiC substrates, among which 3C-SiC was grown as the buffer layer on Si to improve its quality and stability. Growth parameters varied from substrate off-cut angle, growth temperature, P/B ratio and growth time. SWBXT study revealed the basic epitaxial relationships of the BP | |
| dcterms.abstract | SiC films. These were found to be (001)BP | |
| dcterms.abstract | (001)3C-SiC, (111)BP | |
| dcterms.abstract | (111)3C-SiC, (111)BP | |
| dcterms.abstract | (0001)4H-SiC with 4° off-axis along <1-100>4H-SiC or 8° off-axis along <1-100>4H-SiC, (111)BP | |
| dcterms.abstract | (0001)4H-SiC with 4° off-axis along <1-100>4H-SiC or 8° off-axis along <1-100>4H-SiC, (111)BP | |
| dcterms.abstract | (0001)6H-SiC with 3.5° off-axis along <1-100>6H-SiC. The diffraction spots confirmed the single crystalline nature and displayed the general quality of the films. BP diffraction spots, compared to that of SiC substrates, were generally more blurred and overlapped with the some 4H-SiC and 6H-SiC, 3C-SiC and 3C-SiC diffraction spots. Comparison of the observed diffraction patterns with LauePt-simulated patterns of expected compounds revealed the presence of twinned and matrix BP epilayer domains on c-plane 4H-SiC and 6H-SiC substrates, related by a 180° rotation. Also, some unmatched diffraction spots recorded on the patterns indicate the likelihood of B12P2 inclusions. Grazing incidence topographs recorded from these layers were not able to effectively reveal detailed microstructure due to large strains. From the SEM observations, surface roughness and structure differed in each substrate and could be influenced by the growth conditions and substrate type. Among all the samples, (001)BP | |
| dcterms.abstract | (0001)6H-SiC with 3.5° off-axis along <1-100>6H-SiC. The diffraction spots confirmed the single crystalline nature and displayed the general quality of the films. BP diffraction spots, compared to that of SiC substrates, were generally more blurred and overlapped with the some 4H-SiC and 6H-SiC, 3C-SiC and 3C-SiC diffraction spots. Comparison of the observed diffraction patterns with LauePt-simulated patterns of expected compounds revealed the presence of twinned and matrix BP epilayer domains on c-plane 4H-SiC and 6H-SiC substrates, related by a 180° rotation. Also, some unmatched diffraction spots recorded on the patterns indicate the likelihood of B12P2 inclusions. Grazing incidence topographs recorded from these layers were not able to effectively reveal detailed microstructure due to large strains. From the SEM observations, surface roughness and structure differed in each substrate and could be influenced by the growth conditions and substrate type. Among all the samples, (001)BP | |
| dcterms.abstract | (001)3C-SiC film revealed the best surface smoothness, which corroborates the HRXRD measurements that (001)BP | |
| dcterms.abstract | (001)3C-SiC showed lowest FWHM values as well as high epitaxial diffraction intensity. Extensive high-precision measurements of relative out-of-plane lattice mismatch have been conducted, and the high quality (001) BP heterofilms were found to be almost relaxed through the strain-induced defects. Reciprocal space mapping of selected high quality samples suggested that there was no rotational misorientation between the film and substrate. TEM studies on (100)BP | |
| dcterms.abstract | (100)3C-SiC confirmed the existence of B12P2 and its twins, dislocations and stacking faults. Smooth atomic connection was observed at the interface region, without any intermediate layer or second phase. All the results indicate good crystalline quality of (100)BP | |
| dcterms.abstract | (100)3C-SiC and can be potentially applied to devices. 2) Defect studies of CVD grown BP epilayer on c-plane AlN/sapphire substrates. The CVD grown AlN-buffered sapphire films were basically divided into two categories: on-axis (111)BP | |
| dcterms.abstract | (0001)AlN, and 1° off-axis (111)BP | |
| dcterms.abstract | (0001)AlN, and 1° off-axis (111)BP | |
| dcterms.abstract | (0001)AlN. Growth temperatures such as P/B ratio and growth time were varied between samples for comparison. SWBXT revealed the basic epitaxial relationship, which was (111)BP | |
| dcterms.abstract | (0001)AlN with 1° off along <11-20>. Again, diffraction patterns revealed the presence of twinned and matrix BP epilayer domains on c-plane AlN-buffered sapphire substrates, with a 180° rotation on [0001]. SEM images showed high surface smoothness, which corroborated the HRXRD rocking curve measurements, with relatively low FWHM values and the high peak intensities of the BP epilayer. Extensive high-precision measurements of relative in-plane lattice mismatch have been conducted, and the on-axis heterofilms were found to be almost relaxed through the strain-induced defects. Reciprocal space mapping of selected high quality samples suggested that there was no rotational misorientation in the films. General results demonstrate a better quality of the BP | |
| dcterms.abstract | (0001)AlN with 1° off along <11-20>. Again, diffraction patterns revealed the presence of twinned and matrix BP epilayer domains on c-plane AlN-buffered sapphire substrates, with a 180° rotation on [0001]. SEM images showed high surface smoothness, which corroborated the HRXRD rocking curve measurements, with relatively low FWHM values and the high peak intensities of the BP epilayer. Extensive high-precision measurements of relative in-plane lattice mismatch have been conducted, and the on-axis heterofilms were found to be almost relaxed through the strain-induced defects. Reciprocal space mapping of selected high quality samples suggested that there was no rotational misorientation in the films. General results demonstrate a better quality of the BP | |
| dcterms.abstract | AlN system compared with that of BP | |
| dcterms.abstract | SiC system. | |
| dcterms.available | 2017-09-20T16:50:05Z | |
| dcterms.contributor | Dudley, Michael | en_US |
| dcterms.contributor | Raghothamachar, Balaji | en_US |
| dcterms.contributor | T. A., Venkatesh. | en_US |
| dcterms.creator | Wang, Xuejing | |
| dcterms.dateAccepted | 2017-09-20T16:50:05Z | |
| dcterms.dateSubmitted | 2017-09-20T16:50:05Z | |
| dcterms.description | Department of Materials Science and Engineering. | en_US |
| dcterms.extent | 64 pg. | en_US |
| dcterms.format | Monograph | |
| dcterms.format | Application/PDF | en_US |
| dcterms.identifier | http://hdl.handle.net/11401/76356 | |
| dcterms.issued | 2015-12-01 | |
| dcterms.language | en_US | |
| dcterms.provenance | Made available in DSpace on 2017-09-20T16:50:05Z (GMT). No. of bitstreams: 1
Wang_grad.sunysb_0771M_12663.pdf: 13451957 bytes, checksum: a22bbba7b34503c526da90112751ed59 (MD5)
Previous issue date: 1 | en |
| dcterms.publisher | The Graduate School, Stony Brook University: Stony Brook, NY. | |
| dcterms.subject | Materials Science | |
| dcterms.subject | Characterization, HRXRD, Semiconductor, SWBXT, TEM, Thin Film | |
| dcterms.title | Defect Studies and Optimization of CVD Grown Boron Phosphide Films on Different Substrates | |
| dcterms.type | Thesis | |
