M. Hollfelder

InP/InGaAs photodetector based on a high electron mobility transistor layer structure: Its response at 1.3 μm wavelength

We report on the investigation of the room‐temperature optoelectronic behavior of a metal–semiconductor–metal two‐dimensional electron gas photodiode based on the two‐dimensional electron gas of a high electron mobility transistor structure. The photodetector is fabricated in the InP/InGaAs material system, without use of Al‐containing layers. Optoelectronic measurements on a device with a finger spacing of 3 μm show a full width at half‐maximum (FWHM) of the pulse response of ≤60 ps, which is the resolution limit of our measurement equipment. Low‐temperature measurements at 40 K with electro‐optical sampling at a wavelength of 890 nm show a FWHM of 1 ps.

0.1-μm T-gate Al-free InP/InGaAs/InP pHEMTs for W-band applications using a nitrogen carrier for LP-MOCVD growth

We report on the DC and RF performance of HEMTs based on the Al-free material system InP/InGaAs/InP. These structures were grown by LP-MOCVD using a nitrogen carrier. The influence of gate length and channel composition on the performance of these devices is investigated. We demonstrate that optimum DC and RF performance using highly strained channels can be obtained only if additional composite channels are grown. The cutoff frequencies f/sub T/=160 GHz and f/sub max/=260 GHz for a 0.1-/spl mu/m T-gate device indicate the suitability of our devices for W-band applications.

Simple realization of a monolithic integrated photoreceiver for 10 Gbit/s using an InP/InGaAs heterostructure

A novel monolithic integrated photoreceiver for 10 Gbit/s long-wavelength optoelectronic transmission systems is presented. The photoreceiver consists of an MSM photodetector and a HEMT amplifier, prepared on an identical InGaAs/InP 2DEG layer structure. Design considerations, preparation procedure and optoelectronic properties of the photoreceiver under 1.3 /spl mu/m wavelength illumination are presented. The MSM photodetectors exhibit a 3 dB bandwidth of 16 GHz and the HEMT amplifiers have the cut-off frequency f/sub T/ of 45 GHz and f/sub max/, of 85 GHz. A bandwidth of 16 GHz can be achieved on optimized integrated photoreceivers.

0.2 /spl mu/m T-gate InP/InGaAs/InP pHEMT with an InGaP diffusion barrier layer grown by LP-MOCVD using an N/sub 2/-carrier

We report on the development of an Al-free InP/InGaAs/InP HEMT that is grown by LP-MOCVD using an N<inf>2</inf> carrier. We demonstrate that Zn diffusion affects the performance of those HEMTs and can be reduced by inserting an In<inf>0.5</inf>Ga<inf>0.5</inf>P diffusion barrier layer. Devices with a 0.2μm T-Gate yield the cutoff frequencies of f<inf>T</inf>= 135GHz and f<inf>max</inf>= 200GHz. The performance especially of f<inf>max</inf> is limited by the high output conductance and can be improved by reducing the In content of the channel from 77% to 68%.The development of the High Electron Mobility Transistor (HEMT) in the last years resulted in the best RF performance in the material system InAlAs/lnGaAs/InP. Nevertheless, some problems like the kink-effect or photoconductivity arise that are related to aluminium containing layers. These problems can be avoided by using InP instead of InAlAs. InP/InGaAs/InP HEMTs grown by LP-MOCVD using H/sub 2/ as carrier gas demonstrated very good RF performance. We present now the first data of Al-free HEMTs grown by LP-MOCVD using a nitrogen carrier, which improves the growth process in terms of homogeneity, safety and costs. We show that Zn diffusion affects the performance of those HEMTs and can be suppressed by inserting an InGaP layer below the p-doped InP that acts as diffusion barrier for Zn. This diffusion barrier allows smaller gate to channel separations resulting in improved RF performance of f/sub T/=135 GHz and f/sub max/=200 GHz for 0.2 /spl mu/m T-gate HEMTs.