共查询到16条相似文献,搜索用时 156 毫秒
1.
2.
3.
本文基于自主设计的氮化铝生长炉,开展了四组不同工艺条件下Al极性面氮化铝籽晶同质外延生长氮化铝单晶的生长特征及其结晶质量表征研究。研究发现:不同工艺条件下生长的晶体的拉曼图谱E2(high)特征峰峰位表明,晶体内部均存在较小的拉应力;在坩埚顶部在相对较高温度2 210 ℃、坩埚底部与顶部温差42 ℃的低过饱和度生长条件下,晶体表面光滑,呈现阶梯流生长形貌,并具有典型的氮化铝单晶生长习性面,晶体初始扩张角大于40°,高分辨率X射线衍射(HRXRD)测得0002、1012反射摇摆曲线及拉曼光谱检测结果表明,该条件下生长的氮化铝晶体结晶质量优异,并可实现快速扩径。基于该生长条件,通过外延生长后成功获得尺寸ϕ45~47 mm的氮化铝单晶锭,相关表征结果表明生长的氮化铝晶体具有优越的结晶性能。 相似文献
4.
5.
6.
自蔓延高温合成氮化铝晶须形态和生长机理研究(1) 总被引:3,自引:2,他引:1
采用自蔓延高温合成技术(SHS),在高压氮气中成功地合成了氮化铝晶须,并对它的显微结构进行了研究.研究结果表明,由于制备时的生长条件极不稳定,出现不同形态的晶须形貌,除了细长均匀的氮化铝晶须外,还出现了各种其它不规则形状的产物.过饱和度的不同,产生了枝蔓晶结构.按照VS生长方式,在均衡生长条件下,生长为本征结构的氮化铝晶须.晶须顶端的杂质小液滴,为VLS生长方式创造了条件.通过光学显微镜观察,合成出的氮化铝晶须是透明的. 相似文献
7.
8.
采用直流反应磁控溅射与高温退火工艺大批量制备了膜厚为200 nm、400 nm及800 nm的2英寸蓝宝石基氮化铝模板,并对高温退火前后不同膜厚模板使用各种表征手段进行对比分析.结果 表明:采用磁控溅射制备膜厚为200 nm的模板经高温退火后晶体质量得到显著提升,退火前后整片(0002)面和(10-12)面高分辨率X射线衍射摇摆曲线半高宽分别从632 ~ 658 arcsec和2 580 ~2 734 arcsec下降至70.9 ~ 84.5 arcsec和273.6 ~ 341.6 arcsec;模板5 μm×5μm区域内均方根粗糙度小于1 nm;紫外波段260 ~280 nm吸收系数为14 ~20 cm-1;高温退火前后拉曼图谱E2(high)声子模特征峰半高宽从13.5 cm-1降至5.2 cm-1,峰位从656.6 cm-1移动至657.6 cm-1,表明氮化铝模板内的拉应力经高温退火后得到释放,接近无应力状态. 相似文献
9.
10.
11.
12.
Sibin Zuo Jun Wang Xiaolong Chen Shifeng Jin Liangbao Jiang Huiqiang Bao Liwei Guo Wei Sun Wenjun Wang 《Crystal Research and Technology》2012,47(2):139-144
6H‐SiC (0001) deposited 300 nm thick AlN film by MOCVD was used as the substrate to grow AlN crystals by the physical vapour transport (PVT) method. It was confirmed that c‐axis oriented AlN films were grown and this material had a 3D growth mode. The root mean square (RMS) value for the film was measured to be 2.17 nm. Nucleation and further growth of AlN on so prepared substrate was investigated. Colorless and transparent AlN crystal with 1 mm thick and 40 mm in diameter was obtained after 4 h growth on this substrate. The transparent AlN showed strong (0001) texture XRD patterns, only the (0002) reflection was observed in symmetric θ‐2θ scans. The full width at half maximum for a (0002) X‐ray rocking curve was less than 0.1° indicating good crystalline quality. Anisotropic etchings in molten KOH shows that the growth (0001) plane exposed to the AlN source predominately has an aluminum polarity, no N‐polar inversion domains were observed. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
13.
We have obtained single-crystal aluminum nitride (AlN) layers on diamond (1 1 1) substrates by metalorganic vapor-phase epitaxy (MOVPE). When the thermal cleaning temperature of the substrate and growth temperature of the AlN layer were below 1100 °C, the AlN layer had multi-domain structures mainly consisting of rotated domains. An interface layer, consisting of amorphous carbon and poly-crystal AlN, was formed between the AlN layer and the diamond substrate. On the other hand, when the thermal cleaning temperature and growth temperature were above 1200 °C, a single-crystal AlN layer was grown and no interface layer was formed. Therefore, we attribute the multi-domain structures to the interface layer. Even at the growth temperature of 1100 °C, by performing the thermal cleaning at 1200 °C, the single-crystal AlN layer was obtained, indicating that the thermal cleaning temperature of the substrate is a critical factor for the formation of the interface layer. The epitaxial relationship between the single-crystal AlN layer and the diamond (1 1 1) substrate was determined to be [0 0 0 1]AlN∥[1 1 1]diamond and [1 0 1¯ 0]AlN∥[1 1¯ 0]diamond. The AlN surface had Al polarity and no inversion domains were observed in the AlN layer. 相似文献
14.
《Progress in Crystal Growth and Characterization》1988,16(1):53-78
A review is given of the methods which have been used to grow single crystals and epitaxial layers of gallium nitride. In view of the problems in growing bulk crystals, the main emphasis is on heteroepitaxy. Sapphire has been the most popular substrate material, but leads to severe stress because of lattice and expansion mismatch. The use of an intermediate AlN layer appears to alleviate this problem. Chemical vapor deposition using gallium chloride and ammonia has given the highest quality layers to date, but a native donor remains a persistent problem. The use of high pressures of nitrogen offers promise as a means of reducing the native donor concentration. Atomic layer epitaxy is an alternative technique which looks promising for film deposition under well-controlled conditions. The properties of GaN and device considerations are included briefly in this review. 相似文献
15.
16.
W. J. Wang S. B. Zuo H. Q. Bao J. Wang L. B. Jiang X. L Chen 《Crystal Research and Technology》2011,46(5):455-458
The growth of AlN crystals by PVT method was investigated using TaC crucible in the temperature range of 2250‐2350 °C. AlN boules with 30 mm in diameter were successfully grown on the crucible lid by self‐seeded growth. The AlN boules consist of the spontaneously nucleated AlN single crystal grains with the {1010} natural crystalline face. The fast growth rate of more than 1 mm/h was achieved. AlN crystals grown on (11 0)‐, (10 0)‐, and (0001)‐face AlN seeds were investigated. Different experimental phenomena have been observed under particular condition. The crystal grown on (11 0)‐face seed has different natural crystalline face from the seed. For the crystal grown on (10 0) or (0001) seed, the crystal natural crystalline face is same as the crystallographic orientation of the seed. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献