Picosecond Pulse Generators in InP-Based High Electron Mobility Transistor Technology for 10 Gbps Wireless Communication

Characterization of single event effect simulation in InP-based High Electron Mobility Transistors

The performance damage mechanism of InP-based high electron mobility transistors (HEMTs) after proton irradiation has been investigated comprehensively through induced defects. The effects of the defect type, defect energy level with respect to conduction band ET, and defect concentration on the transfer and output characteristics of the device are discussed based on hydrodynamic model and Shockley–Read–Hall recombination model. The results indicate that only acceptor-like defects have a significant influence on device operation. Meanwhile, as defect energy level ET shifts away from conduction band, the drain current decreases gradually and finally reaches a saturation value with ET above 0.5 eV. This can be attributed to the fact that at sufficient deep level, acceptor-type defects could not be ionized any more. Additionally, the drain current and transconductance degrade more severely with larger acceptor concentration. These changes of the electrical characteristics with proton radiation could be accounted for by the electron density reduction in the channel region from induced acceptor-like defects.

The authors report on the state-of-the-art power performance of InP-based HEMTs (high electron mobility transistors) at 59 GHz. Using a 448- mu m-wide HEMT with a gate length of 0.15 mu m, an output power of 155 mW with a 4.9-dB gain and a power-added efficiency of 30.1% were obtained. By power-combining two of these HEMTs, an output power of 288 mW with 3.6-dB gain and a power-added efficiency of 20.4% were achieved. This is the highest output power reported with such a high efficiency for InP-based HEMTs, and is comparable to the best results reported for AlGaAs/InGaAs on GaAs pseudomorphic HEMTs at this frequency. >

Military applications for heterostructure microelectronics technology

We report optical mixing with difference frequencies to 211 GHz in 50 nm gate pseudomorphic InP-based high electron mobility transistors (HEMTs). To our knowledge, this is the highest frequency optical mixing signal obtained in three terminal devices. To detect the signals at these frequencies, a novel three-wave-mixing configuration was employed. To demonstrate the wide tunability of this setup, a sweep of frequencies from 160 to 190 GHz was performed. The optically generated millimeter wave signals were downconverted to 97 GHz and radiated. For the radiation experiments, tunable baseband signals were also added by injection into the gate terminal of our HEMTs, thereby providing a method to transmit information.

An improved recessed-gate structure for high-performance short-gate InP-based InAlAs/InGaAs high electron mobility transistors (HEMTs) is presented. The effective gate length of the HEMTs is found to be related to the electron density in the side-etched region between the gate and the ohmic capped region. The higher electron density in the side-etched region is efficiently suppresses the effective gate length. A new gate recess process, which consists of a sequence of wet-chemical etching and Ar-plasma etching, enables us to reduce the effective gate length. The new recessed-gate structure successfully provides improved performance with high uniformity. A cutoff frequency of 300 GHz is achieved even with 0.07-µm-gate HEMTs.

A 70 nm gate-length In 0.7 Ga 0.3 As/In 0.52 Al 0.48 As InP-based high electron mobility transistor (HEMT) was successfully fabricated with a gate width of 2×20μm and source-drain space of 2 μm. The T-shaped gate with a stem height of 200nm is fabricated to minimize parasitic capacitance. The fabricated devices exhibited a maximum drain current density of 720 mA/mm (V GS =0.2V) and a maximum peak extrinsic-transconductance of 1600 mS/mm. The current gain extrinsic cutoff frequency f T and the maximum oscillation frequency f max were 310 and 540 GHz, respectively. The HEMTs are promising for use in THz-wave integrated circuits.

Toward the realization of ultra-fast wireless communications systems, the inherent broad bandwidth of the terahertz (THz) band is attracting attention, especially for short-range instant download applications. In this paper, we present our recent progress on InP-based THz MMICs and packaging techniques based on low-temperature co-fibered ceramic (LTCC) technology. The transmitter MMICs are based on 80-nm InP-based high electron mobility transistors (HEMTs). Using the transmitter packaged in an E-plane split-block waveguide and compact lens receiver packaged in LTCC multilayered substrates, we tested wireless data transmission up to 27 Gbps with the simple amplitude key shifting (ASK) modulation scheme. We also present several THz antenna-in-packaging solutions based on substrate integrated waveguide (SIW) technology. A vertical hollow (VH) SIW was applied to a compact medium-gain SIW antenna and low-loss interconnection integrated in LTCC multi-layer substrates. The size of the LTCC antennas with 15-dBi gain is less than 0.1 cm3. For feeding the antenna, we investigated an LTCC-integrated transition and polyimide transition to LTCC VH SIWs. These transitions exhibit around 1-dB estimated loss at 300 GHz and more than 35 GHz bandwidth with 10-dB return loss. The proposed package solutions make antennas and interconnections easy to integrate in a compact LTCC package with an MMIC chip for practical applications.

InP-based high electron mobility transistors (HEMTs) will be affected by protons from different directions in space radiation applications. The proton irradiation effects on InAlAs/InGaAs hetero-junction structures of InP-based HEMTs are studied at incident angles ranging from 0 to 89.9° by SRIM software. With the increase of proton incident angle, the change trend of induced vacancy defects in the InAlAs/InGaAs hetero-junction region is consistent with the vacancy energy loss trend of incident protons. Namely, they both have shown an initial increase, followed by a decrease after incident angle has reached 30°. Besides, the average range and ultimate stopping positions of incident protons shift gradually from buffer layer to hetero-junction region, and then go up to gate metal. Finally, the electrical characteristics of InP-based HEMTs are investigated after proton irradiation at different incident angles by Sentaurus-TCAD. The induced vacancy defects are considered self-consistently through solving Poisson’s and current continuity equations. Consequently, the extrinsic transconductance, pinch-off voltage and channel current demonstrate the most serious degradation at the incident angle of 30°, which can be accounted for the most severe carrier sheet density reduction under this condition.

Metal-organic vapor-phase epitaxy (MOVPE) growth of InP was investigated by using both triethylphosphine (TEP) and phosphine (PH/sub 3/) simultaneously as phosphorus sources. Excellent surface morphology was obtained at 630 and 660/spl deg/C by using both TEP and phosphine simultaneously at an optimized balance even though the phosphine supply amount was drastically reduced. The regular monolayer-step array of the sample surface indicates the enhancement of step-flow growth attributed to the enhancement of phosphorus source supply. By using this method, we obtained the InP recess-etching stopper layers of InP-based high electron mobility transistors (HEMTs) with excellent etching selectivity. Low-temperature InP growth at 475/spl deg/C and below was also examined for the growth of emitter in InP-based heterojunction bipolar transistors (HBTs). It is confirmed that this growth method is quite effective for the improvement of InP crystal quality of InP-based epiwafers and the cost reduction for epiwafer production.

An anti-radiation structure of InP-based high electron mobility transistor (HEMT) has been proposed and optimized with double Si-doped planes. The additional Si-doped plane under channel layer has made a huge promotion in channel current, transconductance, current gain cut-off frequency, and maximum oscillation frequency of InP-based HEMTs. Moreover, direct current (DC) and radio frequency (RF) characteristic properties and their reduction rates have been compared in detail between single Si-doped and double Si-doped structures after 75-keV proton irradiation with dose of 5 × 1011 cm−2, 1 × 1012 cm−2, and 5 × 1012 cm−2. DC and RF characteristics for both structures are observed to decrease gradually as irradiation dose rises, which particularly show a drastic drop at dose of 5 × 1012 cm−2. Besides, characteristic degradation degree of the double Si-doped structure is significantly lower than that of the single Si-doped structure, especially at large proton irradiation dose. The enhancement of proton radiation tolerance by the insertion of another Si-doped plane could be accounted for the tremendously increased native carriers, which are bound to weaken substantially the carrier removal effect by irradiation-induced defects.

This paper presents analytical results of the effects of jitter and inter symbol interference (ISI) on a millimeter-wave impulse radio (IR) transceiver, compared with performance of the developed 10-Gb/s W-band IR transmitter prototype. The compact and cost-effective IR transmitter consists of a pulse generator (PG) that creates a short pulse with a duration of <10 ps, a band-pass filter (BPF) that shapes the short pulse to the desired millimeter-wave pulse (wavelet), and a power amplifier (PA) which is deployed as an option. Jitters of the PG and ISI from the BPF are a great issue to make the IR transceiver robust and to obtain excellent performance. One analysis verified that, thanks to a novel retiming architecture, the random jitter and the data dependent jitter from the PG give only a small penalty of <0.5-dB increase in signal to noise ratio (SNR) for achieving a bit error rate (BER) of <10−12. The alternative analysis on the effect of ISI from the BPF indicated that using a Gaussian BPF enables transmission with a BER of <10−12 up to a data rate of 1.4 times as large as a bandwidth of the BPF, whereas the ISI analysis suggested that mismatching of the skirt characteristics of the developed BPF to those of a Gaussian BPF causes tail lobes following the wavelet, resulting in an on/off ratio of <15 dB and hence an SNR penalty of <6 dB.

The HEMT (high electron mobility transistor) LSI perspective is presented, and technological challenges for VLSI are addressed, including the performance advantage in the deep-submicron range, device size and voltage scaled-down approaches, and self-aligned InGaAs-based HEMTs. In addition, the future directions of HEMT technology are projected, focusing on InGaAs-based device technology compared with GaAs-based HEMT LSI technology. >

AlGaN/GaN high electron mobility transistors (HEMTs) have potential applications in the next generation high-power microwave and switching devices. They can maintain robust device characteristics under high temperature operation and high voltage conditions because of their superior material properties [1]. Sapphire and SiC are popularly used as substrate materials for GaN optoelectronic devices. Recently GaN on Si (111) technology has found applications in electronic devices because of its low cost and superior scalability of wafer size. In this study, 0.5µm gate length GaN on Si HEMT technology was proposed and demonstrated with field-plate technology. This GaN on Si HEMT process realized the high performance microwave and power electronics and circuits successfully.

Three mm-wave pulse generation circuits fabricated in a standard 65nm CMOS process are presented. Two versions are based on the cross-coupled NMOS LC-VCO (500um × 300 um), and one is based on the Colpitts VCO (600um × 300 um). No additional buffers are used in the cross-coupled versions, as they are directly loaded by 50 Ohms through a balun. They can produce measured pulses exceeding 8dBm peak output power suitable for impulse radio (IR) systems, and also capable of producing pulses at 6.2pJ/pulse. A drive stage is used in the Colpitts based version to drive 50 Ohm measurement equipment, achieving phase coherent pulses with 8.6pJ/pulse, suitable for pulsed radar applications or IR systems.