共查询到19条相似文献,搜索用时 125 毫秒
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研究了采用MOCVD技术分别在100与500Torr反应室压力下生长的非故意掺杂GaN薄膜的光学与电学性能。研究表明,低压100Torr外延生长条件可以有效地降低Ga与NH3气相反应造成GaN薄膜的碳杂质沾污,从而抑制造成光致发光中黄光峰与蓝光峰的深受主的形成,所制备的材料表现出较好的光学性能。同时,不同生长压力下的GaN薄膜表现出相异的电学性能,即在500Torr下生长的样品通常表现出更高的载流子浓度((4.6-6.4)×1016 cm-3)与更高的迁移率(446-561cm2/(V.s)),而100Torr下生长的样品通常表现为更低的载流子浓度(1.56-3.99)×1016 cm-3与更低迁移率(22.9-202cm2/(V.s))。 相似文献
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本文研究了在Si(111)衬底上生长GaN外延层的方法。相比于直接在AlN缓冲层上生长GaN外延层,引入GaN过渡层显著地提高了外延层的晶体质量并降低了外延层的裂纹密度。使用X射线双晶衍射仪、光学显微镜以及在位监测曲线分析了GaN过渡层对外延层的晶体质量以及裂纹密度的影响。实验发现,直接在AlN缓冲层上生长外延层,晶体质量较差, X射线(0002)面半高宽最优值为0.686°,引入GaN过渡层后,通过调整生长条件,控制岛的长大与合并的过程,从而控制三维生长到二维生长过渡的过程,外延层的晶体质量明显提高, (0002)面半高宽降低为0.206°,并且裂纹明显减少。研究结果证明,通过生长合适厚度的GaN过渡层,可以得到高质量、无裂纹的GaN外延层。 相似文献
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采用金属有机物化学气相沉积(MOCVD)方法生长六方相InN薄膜,利用氮化镓(GaN)缓冲层技术制备了高质量薄膜,得到了其能带带隙0.7eV附近对应的光致发光光谱(PL). 通过比较未采用缓冲层,同时采用低温和高温GaN缓冲层,以及低温GaN缓冲层结合高温退火三种生长过程,发现低温GaN缓冲层结合高温退火过程能够得到更优表面形貌和晶体质量的InN薄膜,同时表征了材料的电学性质和光学性质. 通过对InN薄膜生长模式的讨论,解释了薄膜表面形貌和晶体结构的差异. 相似文献
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基于势垒材料分别为Al0.27Ga0.73N和In0.17Al0.83N的GaN基异质结肖特基二极管(SBD),研究了GaN基异质结的漏电流输运机制、二维电子气密度和反向击穿电压等重要电学特性。结果表明,AlGaN/GaN SBD的反向电流主要由Frenkel-Poole(FP)发射机制主导,而InAlN/GaN SBD的反向电流在低电场下表现为FP发射电流,在高电场下则表现为Fowler-Nordheim隧穿电流。InAlN/GaN SBD的异质界面二维电子气密度明显高于AlGaN/GaN SBD,但是InAlN层存在高密度的缺陷,导致InAlN/GaN SBD的反向漏电流较大,且反向击穿电压较低。 相似文献
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额外HCl和氮化对HVPE GaN生长的影响 总被引:2,自引:0,他引:2
在氢化物气相外延(HVPE)生长Ga N过程中,发现了一种在成核阶段向生长区添加额外HCl来改善Ga N外延薄膜质量的方法,并且讨论了额外HCl和氮化对Ga N形貌和质量的影响.两种方法都可以大幅度地改善Ga N的晶体质量和性质,但机理不同.氮化是通过在衬底表面形成Al N小岛,促进了衬底表面的成核和薄膜的融合;而添加额外HCl则被认为是通过改变生长表面的过饱和度引起快速成核从而促进薄膜的生长而改善晶体质量和性质的 相似文献
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Koh Matsumoto Kazutada Ikenag Jun Yamamoto Kazuki Naito Yoshiki Yano Akinori Ubukat Hiroki Tokunag Tadanobu Arimur Katsuaki Cho Toshiya Tabuchi Akira Yamaguchi Yasuhiro Hara Yuzaburo Ban Kousuke Uchiyama 《半导体学报》2011,32(1):013003-3
Growth rate has a direct impact on the productivity of nitride LED production. Atmospheric pressure growth of GaN with a growth rate as high as 10 μm/h and also Al0.1Ga0.9N growth of 1 μm/h by using 4 inch by 11 production scale MOVPE are described. XRD of (002) and (102) direction was 200 arcsec and 250 arcsec, respectively. Impact of the growth rate on productivity is discussed. 相似文献
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Koh Matsumoto Kazutada Ikenaga Jun Yamamoto Kazuki Naito Yoshiki Yano Akinori Ubukata Hiroki Tokunaga Tadanobu Arimura Katsuaki Cho Toshiya Tabuchi Akira Yamaguchi Yasuhiro Harada Yuzaburo Ban Kousuke Uchiyama 《半导体学报》2011,32(1):21-23
Growth rate has a direct impact on the productivity of nitride LED production.Atmospheric pressure growth of GaN with a growth rate as high as 10μm/h and also Al0.1Ga0.9N growth of 1μm/h by using 4 inch by 11 production scale MOVPE are described.XRD of(002) and(102) direction was 200 arcsec and 250 arcsec, respectively.Impact of the growth rate on productivity is discussed. 相似文献
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H. Tang J. Webb J. Bardwell B. Leathem S. Charbonneau S. Raymond 《Journal of Electronic Materials》2000,29(3):268-273
GaN layers have been grown using an MBE/MSE (molecular beam epitaxy/magnetron sputter epitaxy) dual-mode system. The layers
grown by the two techniques exhibited a large difference in crystalline quality and presented a broad spectrum of structural,
optical, and transport properties that are useful for an analysis of the role of crystalline defects in GaN epilayers. The
model of electron scattering by charged threading dislocations was applied in a theoretical fit of the mobility data. The
theoretical fit in combination with x-ray diffraction and photoluminescence studies reveal the correlation between dislocation
density, electron mobility, doping characteristics and yellow luminescence. 相似文献
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Sun Jung Kim Young Hun Seo Kee Suk Nahm Yun Bong Hahn Hyun Wook Shim Eun-Kyung Suh Kee Young Lim Hyung Jae Lee 《Journal of Electronic Materials》1999,28(8):970-974
The origin of the radiative recombination leading to yellow luminescence (YL) has been elucidated by the study of luminescence
properties of GaN films grown with two different gas feeding methods. GaN films were grown on a (0001) sapphire substrate
in a rapid thermal chemical vapor deposition (RTCVD) reactor. GaN films emitted two different luminescence energies, 2.2 and
3.47 eV, depending on the introducing position of hydrogen gas in the growth reactor. The distribution of the TMGa flow and
gas phase reactions in the reactor were investigated to understand the effect of the gas feeding methods on the optical properties
of GaN films. The results suggest that YL is related to Ga vacancies in the grown films. 相似文献
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MOCVD (metalorganic chemical vapor deposition) of GaN on both silicon and sapphire substrates was studied over the temperature
range of 370 to 1050° C. The crystallinity and surface morphology of the films varied with the deposition temperatures. By
first depositing an AlN buffer layer, the crystallinity of GaN was improved for low temperature depositions, but little improvement
in the surface morphology was observed. On sapphire (0001) substrates, epitaxial layers were produced at a deposition temperature
as low as 500° C. With silicon substrates, polycrystalline films were produced which were randomly oriented on the (111) plane
and highly oriented on the (100) plane. The surfaces of the films were smooth and specular at low deposition temperatures,
but degraded at higher temperatures. The energy band gaps of these films are in the vicinity of 3.4 eV, close to where they
are expected. Elemental analysis by Auger electron spectroscopy (AES) showed the films to be stoichiometric with low residual
impurity concentrations. 相似文献
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Infrared reflectance (IR) of GaN grown on sapphire and silicon substrates has been studied both theoretically and experimentally. The theoretical calculation of the IR spectra is based on the transfer matrix method. The IR spectral characteristics influenced by several factors, such as film thickness, incident angle, free carriers, are systematically examined. Combined with experimental results, surface scattering and interface layer effects are also studied. For GaN epilayers grown on sapphire, carrier concentrations and mobility are determined by fitting to the IR reststrahlen band and compared with the Hall measurement. The interface effect is demonstrated to cause a damping behaviour of the interference fringes away from the reststrahlen band. For GaN grown on Si, the IR spectra predicted the large surface roughness of the epilayers. A variation of IR reststrahlen band is correlated to the microstructures of the films, i.e. their polycrystalline nature of the GaN films grown on Si. A three-component effective medium model is proposed to calculate the IR spectra for polycrystalline GaN, and a qualitative correlation between the IR spectra and structure of the film is established. All results show that IR, as a non-destructive method, is efficient for characterising GaN epilayers in semiconductor processing. 相似文献
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GaN was grown on porous silicon (PS) substrates by Metalorganic Vapour Phase Epitaxy at temperature of 1050 °C. An additional AlN buffer layer is used between GaN and PS. The crystalline quality and surface morphology of GaN films were studied by X-ray diffraction and scanning electron microscope (SEM), respectively. Preferential growth of hexagonal GaN with 〈00.1〉 direction is observed and is clearly improved when the thickness of AlN buffer layer increases. Morphological changes in PS layer appearing after growth have been also discussed.GaN optical qualities were determined by photoluminescence at low and room temperature (RT). 相似文献