共查询到20条相似文献,搜索用时 0 毫秒
1.
P. Y. Timbrell J. M. Baribeau D. J. Lockwood J. P. McCaffrey 《Journal of Electronic Materials》1990,19(7):657-663
Images of electrically active defects in Si1−xGex strained epilayers onn-type Si(100) have been obtained using charge collection microscopy (CCM) in a scanning electron microscope. Electrically
active defects were generated in the defect-free as-grown material by rapid thermal annealing treatments (3 min) over a temperature
range of 550 to 850° C. Point-like contrast, attributed to threading dislocations, as well as an additional line contrast
due to the formation of an interface misfit dislocation network, were observed as the metastable strained Si1−xGrx layers relaxed upon annealing. Cross-sectional and plan-view transmission electron microscopy were used to examine the Si1−xGex epilayers in finer detail. Double crystal x-ray diffraction and Raman scattering spectra were also obtained and the annealing
induced peak shifts investigated. 相似文献
2.
DC and AC electrical properties of amorphous barium titanate thin film capacitors have been investigated as a function of temperature. A clear correlation is found between the temperature dependence of DC leakage currents and the temperature variation of the AC loss peaks, showing that these measurement techniques are probing the same electrical defects. Using either of these two techniques in amorphous barium titanate, we were able to detect oxygen vacancies diffusion with activation energy around 1 eV, and electron traps at 0.3 and 0.4 eV. 相似文献
3.
Redfern D.A. Musca C.A. Dell J.M. Faraone L. 《Electron Devices, IEEE Transactions on》2005,52(10):2163-2174
One of the main limitations in the operability of modern infrared focal plane arrays of p-n junction diodes formed on molecular-beam epitaxy (MBE)-grown HgCdTe is the effect of localized defects. Such defects, including voids, triangles and microvoids, are a feature of the MBE growth regime and can compromise the performance of devices fabricated within the vicinity of electrically active defects. While such defects can often be identified visually, not all defects are electrically active such that they provide a current leakage path shunting the p-n junction of the individual photodiode. In this paper, the use of laser beam-induced current is proposed as a nondestructive characterization technique, and quantitative aspects of its use in the study of electrically active defects in photodiode arrays are examined. 相似文献
4.
本文用单一能级深陷阱模型研究了含深陷阱中心的PN结电容(C)及其微分量((dC)/(dω))与频率(ω)的关系,得到了相应的解析式.理论分析结果表明:电容微分量是一个具有峰值的函数,其峰值、峰位与深陷阱密度及载流子发射时间常数相关.由此提供了一种利用PN结的 C-ω特性确定深陷阱参数的新方法.用此方法,在室温(300K)条件下,测定了 P~+N结中的金受主能级的俘获截面σ_?=(5.6±0.8)×10~(-16)cm~2. 相似文献
5.
6.
A. N. Bright D. M. Tricker C. J. Humphreys R. Davies 《Journal of Electronic Materials》2001,30(3):L13-L16
Al(200 nm)/Ti(20 nm)/n-GaN contacts have been studied using transmission electron microscopy (TEM) and the resulting microstructures
correlated with the observed variation in specific contact resistance (ρc). A minimum ρc value of 7×10−7 Ωcm2 was obtained after annealing at 550°C for 1 min in argon. Bulk metal and interfacial phases have been characterized, and
explanations for the observed electrical behavior are proposed. A transition from TiN to AlN at the interface occurs between
650°C and 700°C. 相似文献
7.
We present a study of electrically active defects induced by ion implantation, for two dopants: arsenic and phosphorous. Our
analysis technique is Deep Level Transient Spectroscopy (D.L.T.S.). We have studied the generation of defects by direct implantation,
and indirect implantation, that is through an SiO2 layer. We follow the defect spectrum evolution for different doses (108 to 1014 atoms/cm2) and for different annealing temperatures (from room temperature up to 800° C). The comparison of our results with other
published ones allows us to improve the knowledge about the role of a protecting oxide layer, the influence of moderate thermal
annealing, and the effect of oxygen on deep centers produced by ion bombardment. 相似文献
8.
《Microelectronic Engineering》2007,84(9-10):2230-2234
The electrically active defects in high-k/SiO2 dielectric stacks are examined using a combination of low frequency noise (LFN) and charge pumping (CP) methods. The volume trap profile in the stacks is obtained by modeling the drain current noise spectra and charge pumping currents, with each technique covering a different depth range. The LFN is dependent on both the high-k and interfacial (IL) SiO2 thicknesses while the CP current is mainly dependent on the IL thickness. 相似文献
9.
10.
The potential of GaN as a wide band gap semiconductor is explored for application as double drift region mixed tunneling avalanche transit time (MITATT) diodes for operation at 120 GHz, 220 GHz and 0.35 THz using some computer simulation methods developed by our group. The salient features of our results have uncovered some peculiarities of the GaN based MITATT devices. An efficiency of more than 20% right up to a frequency of 0.35 THz (from the GaN MITATT diode) seems highly encouraging but a power output of only 0.76 W is indicative of its dismal fate. The existence of a noise measure minimum at the operating frequency of 0.35 THz is again exhilarating but the value of the minimum is miserably high i.e. more than 33 dB. Thus, although GaN is a wide band gap semiconductor, the disparate carrier velocities prevent its full potential from being exploited for application as MTATT diodes. 相似文献
11.
观察了AlGaN/GaN HEMT器件在短期应力后不同栅偏置下的一组漏极电流瞬态,发现瞬态的时间常数随栅偏压变化很小,据此判断这组瞬态由电子陷阱的释放引起.为了验证这个判断,采用数值仿真手段计算了上述瞬态.分别考虑了在器件中不同空间位置的电子陷阱,分析了应力和瞬态中相应的陷阱行为,对比和解释了仿真曲线与测量结果的异同.基于上述讨论,提出测量的瞬态可能是表面深陷阱和GaN层体陷阱的综合作用的结果. 相似文献
12.
观察了AlGaN/GaN HEMT器件在短期应力后不同栅偏置下的一组漏极电流瞬态,发现瞬态的时间常数随栅偏压变化很小,据此判断这组瞬态由电子陷阱的释放引起.为了验证这个判断,采用数值仿真手段计算了上述瞬态.分别考虑了在器件中不同空间位置的电子陷阱,分析了应力和瞬态中相应的陷阱行为,对比和解释了仿真曲线与测量结果的异同.基于上述讨论,提出测量的瞬态可能是表面深陷阱和GaN层体陷阱的综合作用的结果. 相似文献
13.
We report the effect of steam oxidation at 875° C on the electrical resistivity, crystalline quality (measured by ion channeling),
and Al concentration (measured by secondary ion mass spectrometry) in 0.25 μm thick, Si-implanted and recrystallized, Si-on-sapphire
films. After a deep Si implantation (180 keV, 1.4×l015 Si/cm2) at room temperature, and solid-phase epitaxial regrowth from the non-amorphized, 0.03 μm thick surface region, the initially
undoped SOS films become doped p-type, and their resistivity decreases from (1−5)xl014 ficm to 0.5 Ωcm. The doping is due to electrically active Al, released from the A12O3 by the Si implantation, and present in the recrystallized films at a concentration of ≃2×l016 Al/cm3 . After a 75 min steam oxidation at 875 °C, which consumes 0.06 Μm of Si, the resistivity of the recrystallized films increases
to over 40 Ωcm, but the Al concentration is unchanged. The oxidation also uncovers higher quality material below the non-recrystallized
surface layer. A semi-quantitative model is proposed to explain the electrical data, based on the diffusion of oxygen from
the Si/SiO2 interface into the SOS film during oxidation, and the formation of Al-O-Si neutral complexes. Data on the stability of the
high-resistivity films against high-temperature annealing or re-amorphization and annealing is given. 相似文献
14.
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
15.
In this work we demonstrate the effects of a post processing high temperature anneal on the reliability of ultra-thin SiON layers fabricated into both nmos and pmos devices in terms of the initial gate leakage current, stress induced leakage current (SILC), and the time dependent dielectric breakdown behaviour. The devices under consideration were annealed at several temperatures up to 500 °C. We show that different mechanisms dominate the leakage behaviour at different temperatures by examining the relative leakage in the low voltage range. In particular for pmos devices, the emptying of electron traps induced by temperature and subsequent annealing of these traps alters the leakage current profiles significantly, dependent on anneal temperature. We show that annealing improves the time dependent dielectric breakdown (TDDB) lifetimes of nmos devices and examine the reasons for this. 相似文献
16.
少子寿命测试技术是监控单晶硅中杂质和缺陷的数量及性质的重要技术手段.基于常规光电导少子寿命测试的基本参数,研究了不同性质的受主型杂质缺陷对太阳电池用p型单晶硅中少子衰减过程的影响,并重点分析了仅存在受主型电子陷阱或复合中心时,少子衰减过程的变化规律;受主型电子陷阱和复合中心并存时,少子衰减过程的变化规律.研究表明:p型单晶硅中仅存在电子陷阱或复合中心时,二者的密度和俘获截面越小,少子寿命越长,且二者均存在一个最小阈值;当二者并存时,少子电子的衰减过程可根据少子寿命值的不同分成不同的衰减区域. 相似文献
17.
The role of the low temperature buffer layer and layer thickness in the optimization of OMVPE growth of GaN on sapphire 总被引:1,自引:0,他引:1
S. D. Hersee J. Ramer K. Zheng C. Kranenberg K. Malloy M. Banas M. Goorsky 《Journal of Electronic Materials》1995,24(11):1519-1523
In agreement with previous work,12 a thin, low temperature GaN buffer layer, that is used to initiate OMVPE growth of GaN growth on sapphire, is shown to play
a critical role in determining the surface morphology of the main GaN epilayer. X-ray analysis shows that the mosaicity of
the main GaN epilayer continues to improve even after several μm of epitaxy. This continuing improvement in crystal perfection
correlates with an improvement in Hall mobility for thicker samples. So far, we have obtained a maximum mobility of 600 cm2/V-s in a 6 μm GaN epilayer. Atomic force microscopy (AFM) analysis of the buffer layer and x-ray analysis of the main epilayer
lead us to conclude that the both of these effects reflect the degree of coherence in the main GaN epitaxial layer. These
results are consistent with the growth model presented by Hiramatsu et al., however, our AFM data indicates that for GaN buffer
layers partial coherence can be achieved during the low temperature growth stage. 相似文献
18.
The deep level transient spectroscopy (DLTS) technique was used to investigate the effects of electron beam exposure (EBE) on n-GaN. A defect with activation energy of 0.12 eV and capture cross section of 8.0×10–16 cm2 was induced by the exposure. The defect was similar to defects induced by other irradiation techniques such as proton, electron, and gamma irradiation. In comparison to GaN, the EBE induced defects in other materials such as Si and SiC are similar to those induced by other irradiation methods. 相似文献
19.