Hung-Pin Shiao

Mobility and charge density tuning in double δ-doped pseudomorphic high-electron-mobility transistors grown by metal organic chemical vapor deposition

In this article, the authors present mobility and charge density tuning for metal organic chemical vapor deposition (MOCVD)-grown double δ-doped pseudomorphic high-electron-mobility transistors (PHEMTs). Good epitaxial wafers were obtained by MOCVD as indicated by uniform and abrupt interfaces seen in measurements taken using a transmission electron microscope and two pronounced Si-δ-doped peaks in the secondary ion mass spectrometry analysis. The 1-μm-gate-length PHEMT device exhibited good dc performance with a threshold voltage of −1.34V, a maximum drain current of 570mA∕mm, and a maximum transconductance of 279mS∕mm. From the dependences of mobility and charge density between the δ-doping level and spacer layer thickness, most PHEMT design requirements in the ranges between 5750 and 7500cm2∕Vs (for mobility) and 2.4×1012 and 3.6×1012cm−2 (for charge density) can be satisfied.

Mobility and Charge Density Tuning in Double-Doped Enhancement-Mode Pseudomorphic High-Electron-Mobility Transistors Grown by Metalorganic Chemical Vapor Deposition

We present mobility and charge density tuning for metalorganic chemical vapor deposition (MOCVD)-grown double-doped enhancement-mode (E-mode) pseudomorphic high-electron-mobility transistors (PHEMTs) by varying the supplier layer doping level and spacer layer thickness. From the resolvable Pendellosung oscillation in double-crystal X-ray diffraction measurements and a pronounced two-dimensional electron-gas peak in capacitance–voltage (C–V) analyses, good epitaxial wafers are obtained by MOCVD. The 1-µm-gate-length E-mode PHEMT device exhibits a good pinch-off characteristic with a threshold voltage of 0.025 V and a maximum transconductance of 203 mS/mm. The dependences of the pinch-off characteristic in C–V measurement on sheet carrier concentration and spacer layer thickness for E-mode PHEMT application is also described in detail.

High-Temperature and Low-Threshold-Current Operation of 1.5 µm AlGaInAs/InP Strain-Compensated Multiple Quantum Well Laser Diodes

High-temperature and low-threshold-current of 1.5 µm strain-compensated multiple-quantum-well (SC-MQW) graded-index separate-confinement-heterostructure (GRIN-SCH) AlGaInAs/InP laser diodes have been successfully fabricated. An epitaxial wafer was grown by low-pressure metalorganic chemical vapor deposition (LP-MOCVD) and the 2-µm-wide ridge-waveguide (RWG) structure with self-aligned process was adopted. Significant improvements in threshold current high-temperature operation and characteristic temperature have been demonstrated. Under CW operation, these laser diodes exhibited a threshold current of 5.4 mA and 17 mA at 20°C and 100°C, respectively. Output power exceeding 5 mW was obtained at a temperature as high as 120°C. Also they have a characteristic temperature T0 of 90 K between 20°C and 70°C which is as good as the best values of the conventional InGaAsP/InP lasers.

High performance and high reliability of 1.55-μm current-blocking grating complex-coupled DFB lasers

We report the high performance and high reliability of the 1.55 /spl mu/m current-blocking grating complex-coupled InGaAsP strained distributed-feedback MQW lasers. Small variation in slope efficiency, high characteristic temperature, and high side mode suppression ratio have been achieved over a wide temperature range of 20/spl deg/C-90/spl deg/C. From the accelerated aging test, the median life at 25/spl deg/C and 5 mW is estimated to be longer than 50 years.

Growth and Performance Study of Aluminum-Free InGaAs/GaAs/InGaAsP Strained Quantum-Well Pump Lasers

The growth of InGaP, InGaAs and InGaAsP epilayers lattice matched to GaAs using the low pressure organometallic vapor phase epitaxy (LP-OMVPE) system was investigated. For the application of erbium-doped fiber amplifiers (EDFAs), the emission wavelength and far-field pattern of the pump laser were designed. The optical and electrical performances of the resultant pump laser were measured.

Elimination of burn-in effect in metal-organic chemical vapor deposition grown InGaP/GaAs heterojunction bipolar transistors by multistep in situ annealing

The burn-in effect in InGaP/GaAs heterojunction bipolar transistors (HBTs) grown by metal–organic chemical vapor deposition was eliminated by a multistep in situ annealing process. The presence of hydrogen in the HBT base region is the origin of the burn-in effect. An in situ annealing process was conducted during the growth of the emitter cap to reduce the concentration of hydrogen incorporated in the base region. However, diffusion may cause hydrogen to be retrapped in the base and emitter regions during the growth of the residual structure after annealing. In order to eliminate the burn-in effect, a multistep in situ annealing process was evaluated for its ability to overcome the indiffusion of hydrogen. In this investigation, a burn-in effect of less than 5% for metal–organic chemical vapor deposition grown HBTs was achieved without noticeably degrading the device performance by four-step in situ annealing.

High reliability of 1.55 /spl mu/m current-blocking grating complex-coupled DFB lasers

We report the high performance and high reliability of the 1.55 /spl mu/m current-blocking grating complex-coupled distributed-feedback lasers. Small variations in slope efficiency, high characteristic temperature, and high side mode suppression ratio have been achieved over a wide temperature range of 20/spl sim/90/spl deg/C. From the accelerated aging test, the median life for the lasers operating at 25/spl deg/C and 5 mW is estimated to be longer than 50 years.