半绝缘InP的铁掺杂激活与电学补偿

比较了掺Fe和非掺退火半绝缘(SI)InP材料中Fe杂质的分布,掺杂激活机理以及Fe原子与点缺陷的相互作用.原生掺Fe SI-InP中Fe的替位激活主要通过填隙-跳跃机制,但Fe原子易在位错周围聚集,与空位形成复合体缺陷,占据填隙位等,从而降低Fe的激活效率.在FeP2气氛下退火非掺InP获得的SI-InP材料中,Fe原子的激活主要通过扩散过程的"踢出-替位"机制.退火前材料中存在的In空位使Fe原子通过扩散充分占据In位,同时抑制了材料中深能级缺陷的形成.因此,这种SI-InP材料的Fe激活效率高、电学性能好.     

退火处理后非掺磷化铟的电传输特性

利用变温霍尔和电流-电压特性(I-V)两种方法分别对半导体和半绝缘的退火非掺磷化铟材料进行了测量.在非掺退火后的半导体磷化铟样品中可以测到缺陷带电导,这与自由电子浓度较低、有一定补偿度的原生非掺磷化铟的情况类似.非掺SI-InP表现出不同于原生掺铁的SI-InP的I-V特性,在一直到击穿为止的外加电场范围内呈欧姆特性,而掺铁SI-InP的I-V具有与陷阱填充有关非线性特征.根据空间电荷限制电流的理论,这种现象可以解释为非掺SI-InP中没有未被电子占据的空的深能级缺陷.     

高温退火非掺杂磷化铟制备半绝缘材料

对液封直拉(LEC)非掺磷化铟(InP)进行930℃ 80h的退火可重复制备直径为50和75mm的半绝缘 (SI)衬底.退火是在密封的石英管内纯磷(PP)或磷化铁(IP)两种气氛下进行的.测试结果表明IP-SI InP衬底具有很好的电学性质和均匀性,而PP-SI的均匀性和电学参数都很差.在IP-SI样品的PL谱中出现与深缺陷有关的荧光峰.光激电流谱的测量结果表明:在IP气氛下退火获得的半绝缘磷化铟中的缺陷明显比PP-SI磷化铟的要少.并对退火后磷化铟中形成缺陷的机理进行了探讨.     

高温退火非掺杂磷化铟制备半绝缘材料

对液封直拉(LEC)非掺磷化铟(InP)进行930℃ 80h的退火可重复制备直径为50和75mm的半绝缘 (SI)衬底.退火是在密封的石英管内纯磷(PP)或磷化铁(IP)两种气氛下进行的.测试结果表明IP-SI InP衬底具有很好的电学性质和均匀性,而PP-SI的均匀性和电学参数都很差.在IP-SI样品的PL谱中出现与深缺陷有关的荧光峰.光激电流谱的测量结果表明:在IP气氛下退火获得的半绝缘磷化铟中的缺陷明显比PP-SI磷化铟的要少.并对退火后磷化铟中形成缺陷的机理进行了探讨.     

Selective growth of InP on patterned,nonplanar InP substrates by low-pressure organometallic vapor phase epitaxy

The effects of indium sources, mask materials and etched mesa profiles on growth mor-phology of Fe-doped semi-insulating InP on patterned, nonplanar InP substrates were studied for low-pressure organometallic vapor phase epitaxy (OMVPE). The presence or absence of polycrystalline InP layers deposited on the mask was found to depend on the indium source but not on the mask material. Trimethylindium was found to be the preferable indium source for prevention of polycrystalline InP deposits on the mask. The etched mesa shape was found to dominate the final geometry of the OMVPE re-grown InP layer. Inclusion of an interfacial layer of 1.16 μm bandgap wavelength InGaAsP between the dielectric mask and InP substrate produces a favorable mesa shape by con-trolling the level of undercut during mesa etching, so as to form a smooth mesa profile. After selective regrowth of InP over the resulting mesa, a planar surface is typically achieved for mesa stripes with a mask overhang length as long as 2.6 μm and a mesa height as high as 4 μm.     

掺铁浓度对半绝缘磷化铟的一些性质的影响

利用霍尔效应、电流-电压(I-V)、光致发光谱(PL)和光电流谱(PC)研究了不同掺铁浓度的半绝缘InP的性质.半绝缘InP的I-V特性明显地依赖于掺铁的浓度.掺铁的浓度也对半绝缘InP的光学性质和材料中缺陷的形成有影响.用PL和PC分别研究了掺铁半绝缘InP的禁带收缩现象和材料中的缺陷.     

掺铁浓度对半绝缘磷化铟的一些性质的影响

利用霍尔效应、电流-电压(I-V)、光致发光谱(PL)和光电流谱(PC)研究了不同掺铁浓度的半绝缘InP的性质.半绝缘InP的I-V特性明显地依赖于掺铁的浓度.掺铁的浓度也对半绝缘InP的光学性质和材料中缺陷的形成有影响.用PL和PC分别研究了掺铁半绝缘InP的禁带收缩现象和材料中的缺陷.     

退火损伤对Er注入GaAs和Yb注入InP发光的影响

本文报道了CaAs∶Er、InP∶Yb发光样品的二次离子质谱、X-射线双晶衍射测量结果及其与Er离子的表面成份的关系.分析讨论了退火损伤对GaAs∶Er和InP∶Yb发光的影响以及Er~(3+)复合体发光中心模型.     

Effect of annealing conditions on the uniformity of undoped Semi-Insulating InP

Recently, it was found that undoped semi-insulating InP can be obtained by highpressure annealing of high purity materials. The reproducibility and the uniformity was, however, not satisfactory. In the present work, we found that not only Fe concentrations but also Cr and Ni concentrations in annealed wafers were slightly increased during annealing. Since it seems that the origin of the contamination was due to the vapor source of red phosphorus, conductive InP with a trace amount of Fe was annealed under low phosphorus vapor pressure in order to reduce the contamination. By preventing the contamination of Cr and Ni, preparation of semi-insulating InP became highly reproducible. The minimum Fe concentration for realizing semi-insulating InP was found to be 1 x 10¹⁵cm⁻³. It was also found that the better resistivity uniformity can be obtained at higher annealing temperatures.     

Study on microscopic defects in Fe-Doped InP single crystals

Effect of crystal growth conditions on the density of microscopic defects, observed on polished Fe-doped InP LEC single crystal wafers, has been investigated by an interference contrast microscope and a laser scattering tomography (LST) system. It was found that microscopic defects have no correlation with dislocations. Crystal rotation speed affects the density of microscopic defects. In addition, the density depends on the time that the InP melt is held in the molten state before crystal growth. On the other hand, it was found that the H₂O concentration in B₂O₃ has no correlation with the generation of microscopic defects. The relationship between the microscopic defects and the stoichiometry of grown crystals was investigated by coulometric titration analysis. Since the density of microscopic defects is reduced as the indium concentration decreases, it is speculated that their origin is indium or indium oxide.     

退火处理后非掺磷化铟的电传输特性

利用变温霍尔和电流-电压特性(I-V)两种方法分别对半导体和半绝缘的退火非掺磷化铟材料进行了测量.在非掺退火后的半导体磷化铟样品中可以测到缺陷带电导,这与自由电子浓度较低、有一定补偿度的原生非掺磷化铟的情况类似.非掺SI-InP表现出不同于原生掺铁的SI-InP的I-V特性,在一直到击穿为止的外加电场范围内呈欧姆特性,而掺铁SI-InP的I-V具有与陷阱填充有关非线性特征.根据空间电荷限制电流的理论,这种现象可以解释为非掺SI-InP中没有未被电子占据的空的深能级缺陷.     

Compensation mechanisms in nominally undoped semi-insulating InP and comparison with undoped InP grown under stoichiometry control

Nominally undoped semi-insulating InP can be prepared reproducibly by annealing under controlled phosphorus pressure. We present the electrical properties of a large series of undoped InP samples before and after annealing. Spectroscopic investigations show that the specimens are contaminated by iron during annealing, but native defects have to be taken into consideration in order to explain the electrical data. Annealed InP specimens are characterized by electrical and optical measurements and the results are compared to those obtained from InP crystals grown under stoichiometry control by the horizontal gradient freeze technique.     

Deep centers in undoped semi-insulating InP

Undoped semi-insulating (SI) InP samples, subjected to one-step and multi-step wafer annealing, and lightly and normally Fe-doped SI InP samples without annealing have been characterized by thermally stimulated current (TSC) spectroscopy. A dominant deep center at 0.63 eV is found in all samples and is undoubtedly due to iron. Two prominent TSC traps, T_b (0.44 eV) and T_d (0.33 eV), found in undoped SI InP, are thought to be related to the phosphorus antisite P_In, and traps at low temperatures, like T_e* (0.19 eV), to the phosphrus vacancy V_P.     

Cross-sectional TEM of Pd/InP and Au/lnP interfaces formed at substrate temperatures near 300 and 77K

Depositing Pd or Au on InP at cryogenic substrate temperatures has previously been found to significantly increase the barrier height of the resulting Schottky diode. In this work, cross-sectional transmission electron microscopy was used to determine the structural differences between metal/semiconductor (MS) interfaces formed at 300K (RT) and at 77K (LT). In the Pd/lnP case, RT samples exhibited a thick amorphous interaction layer at the MS interface, while LT samples only had a thin phosphorous-rich interfacial layer. However, in the Au/InP case, no amorphous interlayers were observed in any of the samples. Instead, a small amount of Au was found to extend into the InP lattice in the RT case which was not present in LT samples. The thermal stability of the barrier height was studied as well. LT Au/lnP samples were found to exhibit a distinct barrier height shift when annealed at 200°C which was linked to a grain coarsening in the polycrystalline Au layer at this temperature. X-ray diffraction was used to verify changes in the polycrystalline metal's average grain size. We conclude that a significant reduction in the interaction between the deposited metal and InP was responsible for the greatly enhanced barrier height observed in LT interfaces.     

The growth of InP crystals from the melt

The growth of InP crystals from the melt is discussed on the basis of new data on the pTx relations for the In/P system in the vicinity of stoichiometric InP. The preparation of nominally undoped n-type material by the gradient-freeze technique with visual control of the seeding process is described. Zn- and Cd-doped p-type crystals were prepared in a modified almost-isothermal apparatus in order to obtain uniform stoichiometry and regular dopant distribution. The crystals were characterized in terms of their chemical purity, dopant distribution, physical defects and electrical properties.     

Metalorganic vapor phase epitaxial growth,characterization and annealing experiments on InP doping superlattices

InP doping superlattices (DSLs) were grown by atmospheric pressure metalorganic vapor phase epitaxy (MOVPE) and their stability was examined by annealing at high temperatures. Diethylzinc (DEZ) and H₂S were used asp- andn-type doping sources, respectively. Photoluminescence (PL) measurements performed on as grown layers show a shift of the main emission peak with increasing excitation power in very good agreement with theoretical models. A comparison of the PL results between these structures and the annealed samples show that even at very high temperatures (up to 850° C) the tunability of the effective bandgap of the annealed superlattices is possible, although less pronounced than for the as grown layers. This is due to diffusion of the dopants, into adjacent layers and partial compensation of each other. Secondary ion mass spectrometry (SIMS) done on the as grown and annealed samples shows that only the Zn atoms diffuse. Diffusion coefficients obtained from the SIMS profiles give values in the range 1 × 10⁻¹⁴ <D < 9 × 10⁻¹⁴ cm²/s, still smaller than other published values estimated on layers, which did not suffer any treatment. This shows the high quality and stability of our layers even at high temperatures.     

掺Fe或同时掺Fe和Ga半绝缘InP的电学性质分析

本文采取理论计算与实验数据相拟合的方法,简明地图解了掺Fe或同时掺Fe和Ga的半绝缘InP的电学性质.当选取电子与空穴迁移率之比μ_n/μ_p(?)20时,两种材料的Hall迁移率μ_H都得到最佳拟合,与Rhee的结果一致.高温变温Hall数据表明,在迁移率与温度关系上,两种材料存在差异:掺Fe-InP的迁移率随温度升高而减小或基本不变,而同时掺Fe和Ga-InP的迁移率有随温度增加的趋势.     

Reactions between Pd thin films and InP

The reactions between Pd thin films and (001) oriented InP have been studied in detail. Palladium was deposited on InP by electron beam evaporation to a thickness of 60 nm. Specimens were then annealed in vacuum at temperatures up to 500° C for as long as several days. An amorphous ternary phase (Pd≈₃InP) formed during deposition. During annealing, several crystalline ternary phases were detected. Pd₂InP and Pd₅InP were detected at lower annealing temperatures,i.e. from 225–275° C. Pd₂InP grew first, exhibiting an epitaxial relationship with InP, followed by preferred growth of Pd₅InP within the Pd₂InP layer. Both phases later decomposed (≈400° C) producing Pd₂InP(II), which also grew epitaxially on InP. At temperatures greater than 400° C, Pd₂InP(II) decomposed to Pdln and PdP₂, which were thermodynamically stable in contact with InP.     

Diffusion of Cd And Zn In InP between 550 and 650°C

A large number of diffusions have been carried out in sealed quartz ampoules in the temperature range 550–650°C using Zn and Cd in InP. Three-fronted profiles were observed at 650°C for both Cd and Zn and the diffused samples were extensively analysed using Hall measurements, electron beam induced current, electrochemical carrier concentration profiling and thermal probing. These electrical measurements identified the p/n junction unambiguously and indicated a region of high compensation between the p/n junction and the third line. The weight of P added to the ampoule had little effect up to 0.4mg in 0.75cm³ volume at which point a dramatic reduction in diffusion depth for all fronts occurred for increasing P. Diffusion coefficients for Cd and Zn were estimated and plotted as a function of temperature.     

Si-and Be-implantations in lnP:Fe activated by halogen lamp rapid thermal annealing

Halogen lamp rapid thermal annealing is performed at different temperatures and time durations to activate InP:Fe implanted with 200 keV Si and 60 keV Be ions in the range of 5 x 10¹² -4 x 10¹⁴ cm^-2 . Better electrical properties are obtained in the rapid thermal annealed material than in conventional furnace annealed material. The mea-sured maximum dopant activation and electron mobility for a 200 keV/1 x 10¹⁴ cm^-2 Si-implant are 76% and 1440 cm²/V-s, respectively. For a 60 keV/4 x 10¹⁴ cm^-2 Be-implant an activation of 28% and a sheet resistance of 810 Ω/sq are obtained by using rapid thermal annealing. An implant profile broadening is observed in Be-implanted samples activated with either furnace annealing or rapid thermal annealing.