p-i-nInP/In_(0.53)Ga_(0.47)As/InP探测器结构优化

利用半导体仿真工具Silvaco对p-i-n InP/In_(0.53)Ga_(0.47)As/InP近红外光探测器进行优化仿真.参考实际器件对红外探测器进行建模,并将其暗电流、光谱响应仿真结果与实验结果进行拟合,保证仿真结果的有效性.以减小探测器的暗电流为目的,优化其结构.针对探测器吸收层厚度和吸收层掺杂浓度对暗电流、光响应的影响进行研究,发现当吸收层厚度大于0.3μm后,暗电流不再上升,但光响应随着吸收层厚度的增加而增大;当吸收层掺杂浓度不断上升时,器件暗电流不断降低,当掺杂浓度上升到2×1017/cm3时,暗电流达到最低值.本文还研究了p-i-n型探测器的瞬态响应,探究了响应速度与反偏电压之间的关系,发现提高反偏电压能减小探测器响应时间.     

基于silvaco-TCAD的In0.53Ga0.47As/InP红外探测器的仿真

采用silvaco-TCAD研究In0.53Ga0.47As/InP SAGCM-APD光电探测器,对探测器的结构参数对器件的电场分布、击穿电压和贯穿电压的影响进行仿真分析。研究表明电荷层对器件内部电场起到更好的调节作用,但过高的电荷层面密度会导致APD探测器的击穿电压与贯穿电压之差减小。倍增层厚度的增加使击穿电压先减小后增高,贯穿电压线性增加,同时耗尽层宽度变大,使器件电容减小。当倍增区厚度1 μm、偏压为-5 V时,器件电容密度达到了4.5×10-17 F/μm。反向偏置电压为30 V时,APD探测器在1.31 μm和1.55 μm波长下的响应度分别达到1 A/W和1.1 A/W     

InP/In0.53Ga0.47As/InP双异质结双极型晶体管的仿真与分析

运用Silvaco-TCAD软件构建了InP/In_(0.53)Ga_(0.47)As/InP双异质结双极型晶体管模型,研究了掺杂浓度、厚度以及温度对器件特性的影响.结果表明:双异质结双极型晶体管DHBT的开启电压能达到约0.4V,当浓度达到4×10^(19) cm^(-3)的时候,电流增益可以达到一个最佳状态,其峰值能达到约125左右,且浓度对截止频率以及最高振荡频率没有太大的影响;当增大基区厚度时,电流增益会减小,改变厚度能够使DHBT输出特性得以提升,并且提高基区电流的注入;双异质结双极型晶体管具有很好的温度稳定性.     

Analytical modeling and ATLAS simulation of N+-InP/n0-In0.53Ga0.47As/p+-In0.53Ga0.47As p-i-n photodetector for optical fiber communication

In this paper we report an analytical modeling of N⁺-InP/n⁰-In_0.53Ga_0.47As/p⁺-In_0.53Ga_0.47As p-i-n photodetector for optical fiber communication. The results obtained on the basis of our model have been compared and contrasted with the simulated results using ATLAS? and experimental results reported by others. The photodetector has been studied in respect of energy band diagram, electric field profile, doping profile, dark current, resistance area-product, quantum efficiency, spectral response, responsivity and detectivity by analytical method using closed form equations and also been simulated by using device simulation software ATLAS? from SILVACO® international. The photodetector exhibits a high quantum efficiency ～90%, responsivity ～1.152–1.2 A/W in the same order as reported experimentally by others, specific detectivity ～5 × 10⁹ cm Hz^1/2 W^?1at wavelength 1.55–1.65 μm, dark current of the order of 10^?11 A at reverse bias of 1.5 V and 10^?13–10^?12 A near zero bias. These values are comparable to those obtained for practical p-i-n detectors. The estimated noise equivalent power (NEP) is of the order of 2.5 × 10^?14 W.     

Annealing of ion-implanted Ga0.47In0.53As

We have investigated annealing of ion-implanted GaInAs using transmission electron microscopy. We have found that the best condition for the post-implantation anneals for GalnAs is a 30 second anneal at a temperature of 700–800°C. This produces a material similar in character to the untreated GaInAs. Anneals for longer than 30 seconds produce crystal defects becoming increasingly complex with time for similar temperatures.     

Pressure dependence study of the effective mass in Ga0.47In0.53As/InP heterojunctions

A study of the effective mass in GaInAs/InP heterojunctions under hydrostatic pressure up to 15 kbars is presented. Earlier results have shown the importance of hydrostatic pressure effects on the band parameters of the heterojunction to explain the experimental decrease of the carrier concentration with pressure at the interface (1). Here magnetophonon resonance experiments are performed to work out the increase of mass with pressure in our samples. The effective mass at atmospheric pressure is deduced from high temperature cyclotron resonance experiments and then used to calculate the frequency of the phonon interacting with the 2D electron gas (w_o). The value of w_o is found to be dependent on the carrier concentration of the measured samples. The lowest value is found for the highest carrier concentration sample.A band edge effective mass increase of 1 ± .1% kbar is found in the highest carrier concentration sample. This is two times smaller than the rate found experimentally in GaInAs bulk material and slightly smaller than in an AlInAs/GaInAs heterojunction. The experimental increase could be fitted with multiband k.p theory assuming no pressure dependence for the conduction band-valence band matrix element E_p. However at lower concentration a variation of the matrix element E_p with pressure has to be considered.     

Cation diffusion in InP/In0.53Ga0.47As superlattices: strain build-up and relaxation

InP and In_0.53Ga_0.47As are lattice matched and can form superlattices that are free of crystalline defects. Zn indiffusion enhances the diffusion of cations while leaving the anions unaffected; the resultant In_1–x Ga _x P/In_1–x Ga _x As superlattices are strained. Since the as-grown specimens are pseudomorphic, any defects observed after Zn diffusion must be attributed to strain relaxation. Studies of the post-growth strain build-up and relaxation in this novel system suggest a new strain relief mechanism for buried strained layers of face-centred-cubic (fcc) structures. The signature defect of the proposed mechanism is a microtwin along a {111} plane spanning the buried strained layer and terminating at both interfaces with partial dislocations of 1/6112 type. Energy analysis indicates that this new partial-dislocation strain relief mechanism is more effective than the conventional 60 perfect-dislocation mechanism for relieving the in-plane strain in buried strained layers. Therefore, the proposed mechanism is an energetically favourable relaxation channel and limits the useful thicknesses of strained layers in electronic and optoelectronic devices.     

Electron mobilities in isomorphic In0.53Ga0.47As quantum wells on InP substrates

The influence of the doping level, illumination, and width of isomorphic In_0.52Al_0.48As/In_0.53Ga_0.47As/In_0.52Al_0.48As quantum wells grown on InP substrates on the electron mobility is studied. The persistent photoconductivity at low temperatures is found. Band diagrams are calculated and optimal parameters are found for obtaining the maximum electron mobility. The quantum and transport electron mobilities in dimensional quantization subbands are obtained from the Shubnikov-de Haas effect. The electron mobilities are calculated in dimensional quantization subbands upon scattering by ionized impurities taking intersubband transitions into account. Scattering by ionized impurities in samples studied is shown to be dominant at low temperatures.     

生长温度对In0.53Ga0.47As/InP的LPMOCVD生长影响

利用LPMOCVD技术在InP衬底生长了InxGa1-xAs材料，获得表面平整．光亮的In0.53Ga0.47As外延层。研究了生长温度对InxGa1-xAs外延层组分、表面形貌、结晶质量、电学性质的影响。随着生长温度的升高，为了保证铟在固相中组分不变，必须增加三甲基铟在气相中的比例。在生长温度较高时，外延层表面粗糙。生长温度在630℃与650℃之间，X射线双晶衍射曲线半高宽最窄，高于或低于这个温度区间，半高宽变宽。迁移率随着生长温度的升高而增加,在630℃为最大值，然后随着生长湿度的升高反而降低。生长温度降低使载流子浓度增大，在生长温度大于630℃时载流子浓度变化较小。     

Efficient photoluminescence from triangular quantum wells at the interface of an InP/In0.53Ga0.47As heterostructure

Efficient photoluminescence (PL) with quantum yield close to 1 from InP/In_0.53Ga_0.47As heterostructures (HSs) at temperatures 77–300 K and low excitation levels is observed and investigated. The PL is due to a quasi-triangular quantum well (TQW) located at the HS interface and consists of two spectrally similar lines: InGaAs interband emission and emission from the bottom level of the TQW. It is found that as the temperature increases, the intersubband emission rises, while the TQW radiation is quenched. Pis’ma Zh. éksp. Teor. Fiz. 67, No. 10, 783–787 (25 May 1998)     

Two-dimensional electronic transport in In0.53Ga0.47As quantum Wells

Transport properties of the electrons itinerant two dimensionality in a square quantum well of In_0.53Ga_0.47As are studied in the framework of Fermi-Dirac statistics including the relevant scattering mechanisms. An iterative solution of the Boltzmann equation shows that the ohmic mobility is controlled by LO phonon scattering at room temperature, but below 130 K alloy scattering is predominant. The calculated mobilities with a suitable value of the alloy scattering potential agree with the experimental results over a range of lattice temperature. For lattice temperatures below 25 K where the carrier energy loss is governed by the deformation potential acoustic scattering, the warm electron coefficient is found to be negative. Its magnitude decreases with increasing lattice temperature and is greater for larger channel widths. Values of the small-signal AC mobility of hot electrons at a lattice temperature of 4.2 K are obtained for different sheet carrier densities and channel widths. Cut-off frequencies around 100 GHz are indicated.Dedicated to H.-J. Queisser on the occasion of his 60th birthday     

In0.53Ga0.47AS/In0.52Al0.48As量子阱中的正磁电阻效应

在低温强磁场条件下,对In0.53 Ga0.47 As/In0.52AI0.48As量子阱中的二维电子气进行了磁输运测试.在低磁场范围内观察到正磁电阻效应,在高磁场下这一正磁电阻趋于饱和,分析表明这一现象与二维电子气中的电子占据两个子带有关.在考虑了两个子带之间的散射效应后,通过分析低磁场下的正磁电阻,得到了每个子带电子的迁移率,结果表明第二子带电子的迁移率高于第一子带电子的迁移率.进一步分析表明,这主要是由两个子带之间的散射引起的.