Characteristics of native-oxide-confined InGaP-(AlxGa1-x)0.5In0.5P quantum-well ridgewaveguide lasers

We report 670-nm native-oxide confined GaInP-(Al_xGa_1-x)_0.5In_0.5P quantum-well ridge waveguide laser diodes. The devices are fabricated from a compressively strained GaInP-(Al_xGa_1-x)_0.5In_0.5P quantum-well separate confinement heterostructure laser structure. Wet chemical etching and wet oxidation process are used to form native oxide confined ridge waveguides. The oxidation process converts the p-Al_0.5In_0.5P cladding layer into AlO_x after ridge etch. Laser diodes of 3.5-μm-wide ridge waveguide operate with threshold currents below 13.5 mA and differential quantum efficiencies over 35%/facet     

Organometallic vapor phase epitaxial growth of (AlxGa1-x)0.5In0.5P and its heterostructures

Low pressure organometallic vapor-phase epitaxial growth of Ga_0.5In_0.5P and (Al_xGa_1-x) _0.5In_0.5P is examined. Epitaxial layers of bulk materials are characterized using photoluminescence, electroreflectance, Raman scattering spectroscopy, and surface morphology studies to determine lattice match and optimum growth conditions. Lattice matching at the growth temperature produces featureless growth surfaces, while lattice matching at room temperatures results in minimum photoluminescence linewidth but cracked surfaces due to tensile strain during growth. Raman scattering spectra of the quaternary reveal a three mode structure, with spectral peaks due to GaP-like, InP-like, and AIP-like LO phonons. Heterostructures are investigated including quantum shifts from a series of superlattices. These materials are incorporated in double-heterostructure lasers and single-quantum-well laser with graded-index separate confinement heterostructure     

High-temperature DC characteristics of AlxGa0.52-xIn0.48P/GaAs heterojunction bipolar transistors grownby metal organic vapor phase epitaxy

A series of Al_xGa_0.52-xIn_0.48P/GaAs heterojunction bipolar transistors (HBT's) with x=0 to x=0.52 showed ideality factors close to unity for both base current and collector current and small variation in gain with temperature up to at least T=623 K across the whole range of x composition. Hole current injection from the base into the emitter in these devices was shown to be negligible. The current gain, β, which is temperature insensitive was thought to be limited by bulk base recombination for x⩽0.3 and recombination at the graded emitter region for x>0.3. The optimum emitter composition (highest β, and good β stability with collector current and temperature) was found to be x=0.18-0.30. Useful transistor action with very high gain and output resistance is possible up to at least T=623 K, limited only by the thermal performance of the unoptimized ohmic contacts employed in the devices     

Characteristics of a In0.52(AlxGa1-x)0.48As/In0.53Ga0.47As(0⩽x⩽1) heterojunction and its application onHEMT's

The quaternary In_0.52(Al_xGa_1-x) _0.48As compound on InP substrates is an important material for use in optoelectronic and microwave devices. We systematically investigated the electrical properties of quaternary In_0.52(Al_xGa_1-x)_0.48As layers, and found a 10% addition of Ga atoms into the InAlAs layer improves the Schottky diode performance. The energy bandgap (E_g ) for the In_0.52(Al_xGa_1-x)_0.48As layer was (0.806+0.711x) eV, and the associated conduction-band discontinuity (ΔE_c), in the InAlGaAs/In_0.53Ga_0.47 As heterojunction, was around (0.68±0.01)ΔE_g . Using this high quality In_0.52(Al_0.9Ga_0.1)_0.48As layer in the Schottky and buffer layers, we obtained quaternary In_0.52(Al_0.9Ga_0.1)_0.48As/In _0.53Ga_0.47As HEMTs. This quaternary HEMT revealed excellent dc and microwave characteristics. In comparison with the conventional InAlAs/InGaAs HEMT's, quaternary HEMT's demonstrated improved sidegating and device reliability     

Dependently addressable dual-spot native-oxide-confined GaInP-(AlxGa1-x)0.5In0.5Pquantum-well lasers

We describe the fabrication and characteristics of 15-μm spaced dual-spot, 670-nm native-oxide confined GaInP-(Al_xGa_1-x )_0.5In_0.5P quantum-well ridge waveguide laser diodes. The devices are fabricated from a compressively strained GaInP-(Al_xGa_1-x)_0.5In_0.5P quantum-well separate confinement heterostructure laser structure. Wet oxidation of Al_0.5In_0.5P is used to form native-oxide-confined dual-ridge waveguides. The oxidation process converts part of the p-Al_0.5In_0.5P cladding layer into AlO_x after ridge etching. These diodes show excellent performance: uniform low threshold currents of 15 mA and differential quantum efficiencies over 35%/facet. The diodes show crosstalk less than 2%     

低压金属有机化合物气相外延生长的 (Al_x Ga_(1-x))_(0.51)In_(0.49)P折射率测量

采用测量反射谱方法确定了低压金属有机化合物气相外延生长的与 Ga As衬底匹配 (Alx Ga1 - x) 0 .5 1 In0 .49P外延材料的折射率 .实验中测量的反射谱波长范围为 0 .5— 2 .5 μm.在拟合实验数据过程中采用了单振子模型 .折射率数据用于分析应变量子阱 Ga In P/ Al Ga In P可见光激光二极管波导 ,计算出的器件远场图与实验数据吻合很好 .     

Characteristics of short-wavelength (617<λ<640 nm) Ga0.4In0.6P/(AlxGa1-x)0.5In0.5P strained, thin multiple-quantum-well lasers

The authors examine the operating characteristics of short wavelength (617<λ<640 nm) AlGaInP lasers containing three thin (~20 Å) compressively strained Ga_0.4In_0.6 P/(Al_0.6Ga_0.4)_0.5In_0.5 P quantum wells and Al_0.5In_0.5P cladding layers, grown by low pressure organometallic vapor phase epitaxy. At room temperature, wavelengths as short as 617 nm have been achieved, with pulsed threshold current density of 2.5 kA/cm². As a result of greater electron confinement at longer wavelengths, the threshold, and its temperature sensitivity, are improved     

（AlxGa1—x）yIn1—yP Films an Its Optical Constants on the Surface

The optical parameters for three samples of intrinsic,doped Si and doped Mg（AlxGa1-x)yIn1-yP prepared by the MOCVD on GaAs substrate were measured by using ellipsometry and were calculated by the two-layer absorption film model.The results obtained were discussed.The grown rates and thickness of oxidic layer on the intrinsic（AlxGa1-x)yIn1-yP surface exposed in the atmosphere were studied.Alinear dependence of oxidic layer thickness on the time was obtained.     

Al0.25In0.75P/Al0.48In0.52As/Ga0.35In 0.65As graded channelpseudomorphic HEMT's with high channel-breakdown voltage

A new Al_0.25In_0.75P/Al_0.48In_0.52 As/Ga_0.35In 0_.65As pseudomorphic HEMT where the InAs mole fraction of the Ga_1-xIn_xAs channel was graded (x=0.53→0.65→0.53) is described. The modification of the quantum well channel significantly improved breakdown characteristics. In addition, use of an Al_0.25In_0.75P Schottky layer increased the Schottky barrier height. Devices having 0.5 μm gate-length showed g_m of 520 mS/mm and I_max of 700 mA/mm. The gate-drain (BV_g-d) and source-drain (BV_d-s ) breakdown voltages were as high as -14 and 13 V, respectively. An f_T of 70 GHz and f_max of 90 GHz were obtained     

Electron transport across bulk(AlxGa1-x)0.5In0.5P barriersdetermined from the I-V characteristics of n-i-n diodes measured between60 and 310 K

The electron transport characteristics of five n-i-n diodes with (Al_xGa_1-x)_0.5In_0.5P intrinsic barrier regions of various aluminum composition x were determined from the measured I-V characteristics between 60 and 310 K. From these measurements, three different transport regimes were identified. Fowler-Nordheim tunneling was observed at temperatures below 215, 260, 110, 150, and 120 K for aluminum compositions of x=0.4, 0.5, 0.6, 0.7, and 1.0, respectively, with applied electric fields in excess of 5 MV/m. The temperature dependence of the Fowler-Nordheim tunneling currents is shown in AlGaInP for the first time with direct bandgap AlGaInP exhibiting a strong linear decrease in apparent barrier height with increasing temperature. The measured barrier height using the thermionic emission model yields values close to the expected conduction band offset between the GaInP spacer layers and the AlGaInP intrinsic barriers, as measured using high-pressure photoluminescence, and provides a novel technique for measuring the direct-indirect crossover composition in AlGaInP. It is shown that the lowest lying conduction band in AlGaInP is the dominant barrier to electron transport. This has important implications for the design of AlGaInP laser diodes     

Impact ionization rates in (100)Al0.48In0.52As

Impact ionization rates for electrons and holes in (100) Al_0.48In_0.52As were determined from photomultiplication measurements using AlInAs/GaInAs p⁺-i-n diodes grown by metalorganic vapor phase epitaxy (MOVPE). The impact ionization-rate ratio was derived as being 2.0~3.5 over the electric field range from 400 to 650 kV/cm. Ionization rates were found to be smaller than those previously reported. These results could be useful for designing AlInAs/GaInAs superlattice avalanche photodiodes with an electron-initiated configuration     

InP-based HEMT's with Al0.48In0.52AsxP1-x Schottky layers

In this letter we report on the DC and RF performance of InP-based HEMT's with Al_0.48In_0.52As_xP_1-x Schottky layers and GaInAs/InP composite channels. By replacing the Al_0.48In_0.52As Schottky layer with Al_0.48 In_0.52As_xP_1-x we have been able to increase the bandgap of the Schottky layer and achieve record breakdown voltages for 0.15 μm gate-length InP-based HEMT's. The 0.15 μm gate-length HEMT's have gate-to-drain breakdown voltages of over 13 V with current densities of 620 mA/mm and maximum transconductances of 730 mS/mm. On a wafer with a higher sheet charge we have obtained gate-to-drain breakdown voltages of 10.5 V with current densities of over 900 mA/mm. These are the highest breakdown voltages reported for 0.15 μm gate-length InP-based HEMT's with such high current densities. At 10 GHz a 450 μm wide HEMT has demonstrated 350 mW (780 mW/mm) of output power with power-added efficiency of 60% and 12 dB gain     

High-frequency submicrometerAl0.48In0.52As/In0.53Ga0.47As heterostructure bipolar transistors

The high speed scaling of an Al_0.48In_0.52As/In_0.53Ga_0.47 As submicrometer heterostructure bipolar transistor (HBT) is presented. Transistors with emitter dimensions of 0.5×11 and 3.5×3.5 μm² exhibit unity current-gain cutoff frequencies of 63 and 70 GHz, respectively. Emitter current density greater than 3.3×10⁵ A/cm² is demonstrated in a submicrometer AlInAs/InGaAs HBT. The analysis shows that the device speed is limited by the parasitic collector charging time     

AlxGa1−xN Ultraviolet Avalanche Photodiodes Grown on GaN Substrates

Al_xGa_1-xN (x=0.05) ultraviolet (UV) avalanche photodiodes grown on a GaN substrate are reported. The epitaxial structure was grown by metal-organic chemical vapor deposition on a free-standing bulk GaN substrate having low dislocation density. The growth conditions for Al_xGa_1-xN epitaxial layers on GaN substrates were optimized to achieve improved crystalline and structural quality. With UV illumination at lambda~250 nm, devices with mesa diameters of ~30 mum achieve stable maximum optical gains of ~50 at a reverse bias voltage of ~87 V.     

Excess Avalanche Noise in In0.52Al0.48As

Avalanche multiplication and excess noise arising from both electron and hole injection have been measured on a series of In_0.52Al_0.48As p⁺-i-n⁺ and n ⁺-i-p⁺ diodes with nominal avalanche region widths between 0.1 and 2.5 mum. With pure electron injection, low excess noise was measured at values corresponding to effective k=beta/alpha between 0.15 and 0.25 for all widths. Enabled ionization coefficients were deduced using a non-local ionization model utilizing recurrence equation techniques covering an electric field range from approximately 200 kV/cm to 1 MV/cm     

Enhancing the Light Extraction of (Alx Ga1 − x) 0.5In0.5P-Based Light-Emitting Diode Fabricated via Geometric Sapphire Shaping

AlGaInP-based light-emitting diodes (LEDs) with a transparent sapphire substrate were fabricated by the glue-bonding (GB) method. This transparent sapphire substrate is a geometric shaping structure by wet etching processes. Furthermore, the n-side-up surface has a nano-roughened texture by natural mask and chemical wet etching processes. The light output of this novel LED structure could be enhanced about 26.7% (at 350 mA) due to the higher light extraction as compared with the conventional GB-LEDs.     

RIE gate-recessed(Al0.3Ga0.7)0.5In0.5P/InGaAsdouble doped-channel FETs using CHF3+BCl3 mixingplasma

BCl₃+CHF₃ gas mixtures for the reactive ion etching process were applied to the gate-recess for fabricating (Al_0.3Ga_0.7)_0.5In_0.5P quaternary heterostructure double doped-channel FET's (D-DCFET), where a high uniformity of Vth was achieved. With the merits of this wide bandgap (Al_0.3Ga_0.7)_0.5In_0.5P layer, microwave power performance of this heterostructure D-DCFET demonstrates a compatible performance for devices fabricated on AlGaAs/InGaAs heterostructures     

Al0.3Ga0.22In0.48P/GaAs HBT高温特性的研究

本文研制了Al     

长寿命Al_xGa_(1-x)As-GaAs双异质结激光器

本文报导长寿命连续工作的Al_xGa_(1-x)As-GaAs双异质结激光器结构、特性.升温加速老化实验表明,E_α=0.75±0.05电子伏特.由此推算室温下器件寿命可达8万小时以上.