Influence of doping concentration on DC and RF performance of AlGaN/GaN HEMTs on silicon substrate

in Physica Status Solidi A. Applications and Materials Science (2003), (1), 179-182

AlGaN/GaN HEMTs with different carrier supply layers are fabricated on Si substrate, using MOVPE growth technique. The influence of the carrier supply doping concentration on the HEMT properties is ... [more ▼]

AlGaN/GaN HEMTs with different carrier supply layers are fabricated on Si substrate, using MOVPE growth technique. The influence of the carrier supply doping concentration on the HEMT properties is investigated by Hall measurements and by electrical DC and RF characterisation of transistor devices. Hall mobility is found to decrease with increasing sheet concentration, while the gate leakage current increases. The device with the highest carrier supply doping concentration of 1019 cm–3 is provided with a GaN cap layer to reduce gate leakage. The transistors based on modulation doped layer structures show much higher DC performance than the undoped device. Best RF properties are obtained for a doping level of 5 × 1018 cm–3. High frequency measurements exhibit fT and fMAX values of 35 GHz and 37 GHz, respectively, for devices with 300 nm gate length. [less ▲]

0.1 µm T-gate Al-free InP/InGaAs/InP pHEMTs for W-Band Applications Using a Nitrogen Carrier for LP-MOCVD Growth

in IEEE Electron Device Letters (1997), 18

We report on the dc and RF performance of HEMT’s 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 ... [more ▼]

We report on the dc and RF performance of HEMT’s 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 fT =160 GHz and fmax=260 GHz for a 0.1- um T-gate device indicate the suitability of our devices for W-Band applications. [less ▲]

Novel HEMT layout: The RoundHEMT

in Electronics Letters (1995), 31(1995), 589-591

Submicrometer Silicon Permeable Base Transistors with Buried CoSi2 Gates

in Electronics Letters (1993), 29(1993), 215-217