High-Performance In0.23Ga0.77As Channel MOSFETs with High Current Ratio Ion/Ioff Grown on Semi-insulating GaAs Substrates by MOCVD

We demonstrate high-performance In0.23 Ga0.77 As channel metal-oxide-semiconductor field-effect transistors （ MOS- FETs） with high on-current to off-current （Ion/Ioff） ratio grown on semi-insulating GaAs wafers by metal-organic chemical vapor deposition （MOCVD）. The 2μm channel-length devices exhibit a peak extrinsic transeonductance of 150 mS/mm and a drain current up to 500 mA/mm. The maximum effective mobility is 1680 cm2/Vs extracted by the split C-V method. Furthermore, the Ion/Ioff ratio is significantly improved from approximately 4.5 × 10^3 up to approximately 4.32 × 10^4 by controlling the etch thickness of In0.49Ga0.51P, The high drain current and high Ion/Ioff ratio of the In0.23Ga0.77As channel MOSFETs are achieved due to the high effective mobility and the low gate leakage current density.

Growth and Characterization of InAs1-xSbx with Different Sb Compositions on GaAs Substrates

InAs1-xSbx with different compositions is grown by molecular beam epitaxy on （100）-oriented semi-insulating GaAs substrates. The increase of Sb content in the epilayer results in the deterioration of crystal quality and surface morphology. Hall measurements show that the carrier concentration increases with the composition of Sb. The electron mobility decreases initially, when Sb composition exceeds a certain value, and the mobility increases slightly. In this work, we emphasize the comparison of crystal quality, surface morphology and electrical properties of epilayers with different Sb compositions.

Fabrication of 150-nm Al_(0.48)In_(0.52)As/Ga_(0.47)In_(0.53)As mHEMTs on GaAs substrates

High performance 150-nm gate-length metamorphic Al0.48In0.52As/Ga0.47In0.53 As high electron mobility transistors(mHEMTs) with very good device performance have been successfully fabricated.A T-shaped gate is fabricated by using a combined technique of optical and e-beam photolithography,which is beneficial to decreasing parasitic capacitance and parasitic resistance of the gate.The ohmic contact resistance R c is as low as 0.03 mm when using a novel ohmic contact metal system(Ni/Ge/Ti/Au).The devices exhibit excellent DC and RF performance.A peak extrinsic transconductance of 775 mS/mm and a maximum drain current density of 720 mA/mm are achieved.The unity current gain cut-off frequency(fT) and the maximum oscillation frequency(f max) are 188.4 and 250 GHz,respectively.

Metamorphic growth of 1.55 μm InGaAs/InGaAsP multiple quantum wells laser structures on GaAs substrates

We fabricate a GaAs-based InGaAs/InGaAsP multiple quantum wells （MQWs） laser at 1.55 pm. Using two-step growth method and thermal cyclic annealing, a thin low-temperature InP layer and a thick InP buffer layer are grown on GaAs substrates by low-pressure metal organic chemical vapor deposition technology. Then, high- quality MQWs laser structures are grown on the InP buffer layer. Under quasi-continuous wave （QCW） condition, a threshold current of 476 mA and slope efficiency of 0.15 mW/mA are achieved for a broad area device with 50 μm wide strip and 500 μm long cavity at room-temperature. The peak wavelength of emission spectrum is 1549.5 nm at 700 mA. The device is operating for more than 2000 h at room-temperature and 600 mA.

Fabrication of 80-nm T-gate high indium In_(0.7)Ga_(0.3)As/In_(0.6)Ga_(0.4)As composite channels mHEMT on GaAs substrate with simple technological process

An 80-nm gate length metamorphic high electron mobility transistor （mHEMT） on a GaAs substrate with high indium composite compound-channels Ino.7Ga0.aAs/Ino.6Gao.aAs and an optimized grade buffer scheme is presented. High 2-DEG Hall mobility values of 10200 cm2/（V.s） and a sheet density of 3.5 x 10^12 cm-2 at 300 K have been achieved. The device＇s T-shaped gate was made by utilizing a simple three layers electron beam resist, instead of employing a passivation layer for the T-share gate, which is beneficial to decreasing parasitic capacitance and parasitic resistance of the gate and simplifying the device manufacturing process. The ohmic contact resistance Rc is 0.2 n.mm when using the same metal system with the gate （Pt/Ti/Pt/Au）, which reduces the manufacturing cycle of the device. The mHEMT device demonstrates excellent DC and RF characteristics. The peak extrinsic transconductance of 1.1 S/mm and the maximum drain current density of 0.86 A/mm are obtained. The unity current gain cut-off frequency （fT） and the maximum oscillation frequency （fmax） are 246 and 301 GHz, respectively.

Influence of GaAs substrate on the transmission performance of epitaxially grown Fabry-P'erot filter

The influence of GaAs substrate on the transmission performance of a multi-film Fabry-P＇erot filter （FPF）,fabricated by metalorganic chemical vapor deposition epitaxial growth on GaAs substrate,is investigated using the transfer matrix method.On the basis of the theoretical simulation,we determine that the quality of the resonant transmission peak of this epitaxially grown FPF （EG-FPF） deteriorates through splitting when the substrate is taken into account.Rapid periodic oscillation of peak-transmittivity along with the alteration of substrate thickness is also observed in the simulation results.Finally,a remarkably improved transmission performance of the EG-FPF is obtained by thinning the substrate down to a suitable thickness range through well-controlled grinding and polishing.

Temperature-Dependent Photoluminescence Characteristics of InAs/GaAs Quantum Dots Directly Grown on Si Substrates

The first operation of an electrically pumped 1.3μm InAs/GaAs quantum-dot laser was previously reported epitaxially grown on Si （100） substrate. Here the direct epitaxial growth condition of 1.3μm InAs/OaAs quantum on a Si substrate is further investigated using atomic force microscopy, etch pit density and temperature-dependent photoluminescence （PL） measurements. The PL for Si-based InAs/GaAs quantum dots appears to be very sensitive to the initial OaAs nucleation temperature and thickness with strongest room-temperature emission at 40000 （17Onto nucleation layer thickness）, due to the lower density of defects generated under this growth condition, and stronger carrier confinement within the quantum dots.

Study on the performance of thin-film VCSELs on composite metal substrate

Thin film p-side up vertical-cavity surface-emitting lasers(VCSELs)with 940 nm wavelength on a composite metal(Copper/Invar/Copper;CIC)substrate has been demonstrated by twice-bonding transfer and substrate removing techniques.The CIC substrate is a sandwich structure with a 10µm thick Copper(Cu)layer/30µm thick Invar layer/10µm thick Cu layer.The Invar layer was composed of Iron(Fe)and Nickel(Ni)with a proportion of 70:30.The thermal expansion coefcient of the composite CIC metal can match that of the GaAs substrate.It results that the VCSEL layers can be successfully transferred to CIC metal substrate without cracking.At 1 mA current,the top-emitting VCSEL/GaAs and thin-flm VCSEL/CIC had a voltage of 1.39 and 1.37 V,respectively.The optical output powers of VCSEL/GaAs and VCSEL/CIC were 21.91 and 24.40 mW,respectively.The 50µm thick CIC substrate can play a good heat dissipation function,which results in improving the electrical and optical characteristics of thin flm VCSELs/CIC.The VCSEL/CIC exhibited a superior thermal management capability as compared with VCSEL/GaAs.The obtained data suggested that VCSELs on a composite metal substrate not only afected signifcantly the characteristics of thin film VCSEL,but also improved considerably the device thermal performance.

An improved single-π equivalent circuit model for on-chip inductors in GaAs process

An improved single-π equivalent circuit model for on-chip inductors in the GaAs process is presented in this paper. Considering high order parasites, the model is established by comprising an improved skin effect branch and a substrate lateral coupling branch. The parameter extraction is based on an improved characteristic function approach and vector fitting method. The model has better simulation than the previous work over the measured data of 2.5r and 4.5r on-chip inductors in the GaAs process.