共查询到16条相似文献,搜索用时 125 毫秒
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采用同步辐射光电子能谱(SRPES)结合扫描电子显微镜(SEM)和称量法,研究了中性(NH4)2S溶液钝化GaAs(100)表面,并与常规(NH4)2S碱性溶液钝化方法进行了比较- SRPES结果表明该处理方法可以产生较厚的Ga硫化物层和较强的Ga—S键,Ga的硫化物有好的稳定性-称量法表明该方法有更低的腐蚀速率-SEM结果表明该方法钝化处理的GaAs表面所产生的腐蚀坑数目少,直径小-
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为了有效降低GaAs半导体表面态密度,提出了采用正十八硫醇(ODT,CH3[CH2]17SH)进行GaAs表面钝化的方案。首先,分别对GaAs(100)晶片进行了常规硫代乙酰胺(TAM,CH3CSNH2)钝化和正十八硫醇钝化,通过X射线光电子能谱(XPS)对比分析了钝化前后晶片表面的化学成分,然后利用光致发光光谱(PL)对正十八硫醇处理的GaAs(100)晶片进行了钝化时间的优化,最后通过扫描电子显微镜(SEM)测试了钝化前后的晶片表面形貌。实验结果表明:采用正十八硫醇钝化的GaAs(100)表面,相比常规硫代乙酰胺钝化方案,具有更低的氧化物含量和更厚的硫化层厚度;室温钝化条件下,钝化时间越长,正十八硫醇的钝化效果越好,但PL强度在钝化超过24 h后基本达到稳定,最高PL强度提高了116%;正十八硫醇钝化的GaAs(100)晶片具有良好的表面形貌,表面形成了均匀、平整的硫化物钝化层。数据表明正十八硫醇是钝化GaAs(100)表面一种非常有效的技术手段。 相似文献
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利用光致发光谱、X射线光电子谱和俄歇电子谱等技术研究了(NH_4)_2S_x和P_2S_5/(NH_4)_2S_5化学钝化GaAs(100)表面.结果表明,(NH_4)_2S_x中S钝化可以完全去除GaAs表面的氧化物.P_2S_5/(NH_4)_2S_x中P_2S_5对降低G_2A_5表面态密度,提高光致发光强度是有效的.钝化表面P氧化物存在对防止GaAs表面初期氧化起重要作用.
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利用低能电子衍射(LEED)、X射线光电子能谱(XPS)、电子能量损失谱(EELS)、紫外光电子能谱(UPS),对室温下Mn在GaAs(100)4×1表面的淀积过程进行了研究。研究结果表明,当锰的覆盖度θ≥0.25nm时,LEED图案完全消失,表明Mn没有生长成单晶。LEED,EELS的结果都表明淀积初期是层状生长的。对XPS的Ga2p3/2,As2p3/2的峰形、强度进行分析,可以知道在很小的覆盖度下,Mn就与衬底反应。置换出的Ga被局限在离原来的界面约3nm
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为实现GaAs表面的钝化,以Na2S、(NH4)2S、CH3CSNH2为主要研究对象,通过对比实验研究得出较为理想的湿法钝化液。通过光致发光(PL)谱研究了(NH4)2S 叔丁醇、CH3CSNH2 NH4OH、CH3CSNH2 叔丁醇三种不同含硫溶液钝化(100)GaAs表面后的发光特性。PL谱测试发现,(NH4)2S 叔丁醇饱和溶液处理过的(100)GaAs表面光致发光强度最强,PL谱的相对发光强度是未做钝化处理的10倍左右。因此得出(NH4)2S 叔丁醇饱和溶液是较为理想的(100)GaAs表面钝化液。 相似文献
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本文采用原位X射线光电子能谱、紫外光电子能谱、高分辨率电子能量损失谱和低能电子衍射技术,研究了温度对P与GaAs(100)表面相互作用的影响。结果表明,经退火后,室温下淀积于GaAs表面的非晶P大部分脱附,仅剩下少量无规分布于表面的P集团。集团中部分P与衬底Ga原子成键,另一部分P则以单质形式存在,继续提高温度退火,将使P集团中的P全部与衬底发生反应生成GaAsP薄层。在高温GaAs衬底上淀积P,将得到GaAsP固溶体薄层。这一薄层有望成为GaAs表面理想的钝化膜。
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M. Nishida 《Solid State Communications》1979,31(7):513-516
Inward relaxation effects of the outermost Ga layer on the electronic structure of GaAs (111) Ga and outward expansion effects of the outermost As layer on that of GaAs () As are studied by extended Hückel theory. Three different surface geometries are examined for the respective surfaces. It is shown that upon relaxation on GaAs (111) or upon expansion on GaAs () new surface states associated with dangling- and back-bonds are revealed. The character and dispersion behaviour of strongly localized surface states are described. 相似文献
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Weichao Wang Geunsik Lee Robert M. Wallace Kyeongjae Cho 《Applied Surface Science》2010,256(22):6569-6573
First principles calculations of HfO2/GaAs interfaces indicate that the interface states originate from the charge mismatch between HfO2 and GaAs surfaces. We find that a model neutral interface (HfO2 and GaAs surfaces terminated with two O and one Ga atoms per surface unit cell) removes gap states due to the balance of the interface charge. F and H can neutralize the HfO2/GaAs interface resulting in useful band offsets, thus becoming possible candidates to passivate the interface states. 相似文献
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Xuefei LiAidong Li Xiaojie LiuYoupin Gong Xiaochun ChenHui Li Di Wu 《Applied Surface Science》2011,257(10):4589-4592
The Ge surfaces were cleaned and passivated by two kinds of chemical pretreatments: conventional combination of HF + (NH4)2S, and new one of HBr + (NH4)2S. The chemical states and stability at passivated Ge surfaces were carefully characterized. The influence of chemical surface treatments on the interface and electrical properties of Al2O3 gate dielectric films on Ge grown by atomic layer deposition (ALD) has been investigated deeply. It is found that the combination of HBr and (NH4)2S can remove more Ge-O bonds on the Ge surface compared to that of conventional HF and (NH4)2S with excellent stability. X-ray photoelectron spectroscopy (XPS) reveals that HBr and (NH4)2S treated Ge surface has a mixture states of GeOx (9.25%) and GeS (7.40%) while HF and (NH4)2S treated Ge surface has a mixture states of GeOx (16.45%) and GeS (3.37%). And the Ge-S peak from the surface of Ge substrates decreases a little after the HBr and (NH4)2S treated Ge surface was exposed in the ambient for 300 min, which suggests the Ge surface is stable to oxidants. The Al2O3 films on HBr and (NH4)2S treated Ge substrates exhibits better electrical properties such as large capacitance, decreased leakage current density by ∼two orders of magnitude, and less C-V hysteresis. This indicates that a reduction in charge traps possibly at the interface and more interface traps are terminated by sulfur. The surface treatment of HBr and (NH4)2S seems to be very promising in improving the quality of high-k gate stack on Ge substrates. 相似文献
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Improvement of Atomic-Layer-Deposited Al2O3/GaAs Interface Property by Sulfuration and NH3 Thermal Nitridation 下载免费PDF全文
Fermi level pinning at the interface between high-h gate dielectric and GaAs induced by unstable native oxides is a major obstacle for high performance GaAs-based metal-oxide-semiconductor (MOS) devices. We demonstrate the improved Al2O3/GaAs interracial characteristics by (NH4)2S immersion and NH3 thermal pretreatment prior to A1203 deposition. X-ray photoelectron spectroscopy (XPS) analysis confirms that sulfuration of GaAs surface by (NH4 )2S solution can effectively reduce As-O bonds while Ga-O bonds and elemental As still exist at Al2O3 /GaAs interface. However, it is found that N incorporation during the further thermal nitridation on sulfurated GaAs can effectively suppress the native oxides and elemental As in the sequent deposition of Al2O3. Atomic force microscopy (AFM) shows that the further thermal nitridation on sulfurated GaAs surface can also improve the surface roughness. 相似文献
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The regions around the respective carbon, nitrogen and oxygen K-edges of CH4, NH3, H2O, CH3OH, CH3OCH3 and CH3NH2 have been investigated by electron energy loss spectroscopy using a beam of 2.5 keV electrons. All spectra show a number of discrete peaks just below the K-shell ionization threshold. These discrete structures have been interpreted as being associated with the promotion of a K-shell electron to Rydberg orbitals which converge to the K-shell ionization threshold. 相似文献
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Yusuke Mizokawa Hiroshi Iwasaki Ryusuke Nishitani Shogo Nakamura 《Journal of Electron Spectroscopy and Related Phenomena》1978,14(2):129-141
The binding energies of Ga 3d, As 3d, Ga L3M4,5M4,5 and O 1s in Ga, As, GaAs, Ga2O3, As2O3 and As2O5 are reevaluated by means of ESCA. The calibration lines of the C 1s and the Au 4f gave different binding energies for the compound materials. In order to determine the absolute binding energies, the chemical shifts in Auger and photoelectron lines from a layered structure composed of thin layer oxide and substrate of a defined material were used. An energy calibration curve, E(Ga 3d) vs. ΔE(GA LMM - Ga 3d), was found to be useful for determination of binding energies in the material which contains gallium. In the case of the GaAs sample, both the chemical etching and the ion bombardment effects on the chemical structure of the GaAs surface are also discussed. 相似文献