InP-based HEMTs Research Articles

Accurate on Wafer Calibration and S-parameter Measurement Setup for InP-based HEMT Devices to 220 GHz

Accurate on Wafer Calibration and S-parameter Measurement Setup for InP-based HEMT Devices to 220 GHz

Effects of electron irradiation on analog and linearity performance of InP-based HEMT

Effects of electron irradiation on analog and linearity performance of InP-based HEMT

Influence of BCB Protection on Irradiation Response of InP-Based HEMTs: A Comparative Study

Influence of BCB Protection on Irradiation Response of InP-Based HEMTs: A Comparative Study

Improvement of single event effects in InP-based HEMT with a composite channel of InGaAs/InAs/InGaAs

In this paper, a hardened single event effects in InP-based HEMT with a InGaAs/InAs/InGaAs composite channel (CC HEMT) is investigated by the two-dimensional numerical simulations. The composite channel significantly improves the single event effects. Compared to the conventional InP-based HEMT with single InGaAs channel (SC HEMT), the peak drain current is markedly decreased for CC HEMT, owing to a high barrier in the InGaAs/InAs/InGaAs locates electrons in the middle of the sandwiched layer. In addition, the electron concentration of the InAs channel is smaller of CC HEMT than that of InGaAs channel of SC HEMT after ion strike. This also makes the decrease in drain current. Through optimal device parameters, the peak drain current of the CC HEMT with 9/1/5 nm In0.8Ga0.2As/InAs/In0.8Ga0.2 channel is 129.1 % smaller than that of the SC HEMT with In0.53Ga0.47 channel.

An Accurate Model for InP HEMT Small-Signal Equivalent Circuit Based on EM Simulation

A high-reliability small-signal equivalent circuit model for indium-phosphide-based high-electron-mobility transistors (InP-based HEMTs) is proposed. A de-embedding scheme for the representative structure is utilized in this model with an electromagnetic simulation approach to consider the distributed extrinsic parasitic elements. The intrinsic part of the small-signal model is directly extracted with the Y-parameter of the intrinsic two-port network. The extraction of the parametric elements was performed under different biases and three different gate widths ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 20\,\,\mu \text{m}$ </tex-math></inline-formula> , <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 30\,\,\mu \text{m}$ </tex-math></inline-formula> , and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 50\,\,\mu \text{m}$ </tex-math></inline-formula> ), our S-parameter predictions showed good agreement with measurements in the 1–50-GHz frequency range. The proposed model performs an electromagnetic simulation of different gate-width devices, considers the devices’ distribution and radio-frequency behavior, and avoids errors caused by traditional tests’ extraction of parasitic parameters. The proposed model solves the problem that the conventional indium phosphide-based HEMT small-signal model is limited by the device topology, making the high-frequency modeling more accurate.

Study of single event effect for the InP-based HEMT with In0.53Ga0.47As/In0.3Ga0.7As/In0.7Ga0.3As composite channel

In this study, the single event effects in In0.53Ga0.47As/In0.3Ga0.7As/In0.7Ga0.3As composite channel InP-based HEMT are investigated using TCAD simulation for the first time. Due to the higher conduction band difference between bottom In0.7Ga0.3As channel and InAlAs buffer, the electrons in the buffer layer induced by ions strike cannot enter the channel, led to reduce the peak concentration in the composite channel and significantly weakened the drain current for composite channel device. Meanwhile, higher barrier height under the gate for composite channel InP-based HEMT is formed after particle strike, and further attenuate the drain current. Therefore, the single event effects can be effectively reduced by designing channel structure. In addition, drain voltage and incident position also show significant impact drain current. With the increase in the drain voltage, the drain current increase and the most sensitive incident position is the gate electrode for the device.

Influence of double InGaAs/InAs channel on DC and RF performances of InP-based HEMTs

The double InGaAs/InAs channel structure is designed to improve DC and RF characteristics of InP-based HEMT, which is studied by the numerical simulation. The saturated channel current, transconductance, subthreshold slope, drain induced barrier lowering, and frequency characteristics are analyzed. A comparison is done between the device with the double InGaAs/InAs channel and InGaAs channel. By using double InGaAs/InAs channel, maximum transconductance of 1019.7 mS/mm is achieved, and the lower value of subthreshold slope and drain induced barrier lowering is also obtained. The excellent performance of device with double InGaAs/InAs channel structure is mainly due to the enhanced confinement of the electrons in the channel region. In addition, the maximum oscillation frequency of 758.7 GHz is obtained with the double InGaAs/InAs channel structure.These results indicate that InP-based HEMT with double InGaAs/InAs channel structure is a promising candidate for high frequency application.

Improvement of Single Event Effects in Inp-Based Hemt with a Composite Channel of Ingaas/Inas/Ingaas

Improvement of Single Event Effects in Inp-Based Hemt with a Composite Channel of Ingaas/Inas/Ingaas

A study of gate recess-width control of InP-based HEMTs by a Si3N4 passivation layer

Recess process for opening a narrow trench in the capping layer for T-shaped gates is one of the most important steps in the fabrication of InP-InAlAs/InGaAs based high electron mobility transistors, since the recessed-width strongly influences the DC/RF performances of the devices. Conventional chemical wet etch fails to well control the recess-width and its uniformity, leaving the seemingly small issue still rarely addressed so far. This work quantitatively analyzed the relationship between the recess-width and the DC/RF properties of the device by numerical simulations. To enhance the controllability of the recess-width, a 20-nm thick Si3N4 passivation layer pre-grown on the top of the capping layer was proposed. Careful comparisons of the recess-width as well as the device property with and without the passivation layer was carried out. Our results from both experiments and simulations indicate that it is promisingly feasible to control the recess-width to the desired scale by chemical wet etch when a dielectric layer such as Si3N4 is applied to protect the InGaAs capping layer from being over recessed, leading to enhanced device performance. With such an additional Si3N4 passivation layer, it is expected that the manufacturing yield of the InP-based high electron mobility transistors should be significantly enhanced with improved device performances.

Electron irradiation effects on InP-based HEMTs with different gate widths

In this paper, the influence of electron irradiation on DC and RF characteristics of InP-based HEMTs with different gate widths were studied by irradiation experiment. The results show that the value of channel current (IDS) and transconductance (gm) are decreased for device with different gate width after electron irradiation, which is mainly due to the reduction of mobility in the channel by the irradiation-induced defects. However, the carrier concentration in the channel has a little change. Compared with the device with 100 μm gate width, IDS and gm of the device with 40 μm gate width were decreased by 1.5% and 3%. Meanwhile, the forward gate current decreased due to the increase of series resistance of gate contact caused by electron irradiation. The interface defects induced by electron irradiation induced the increase of the reverse gate current. Additionally, the current gain cut-off frequency (fT) and maximum oscillation frequency (fmax) were reduced by 19.8% and 10.9% for device with 40 μm gate width, and the fT and fmax were only reduced by 7.1% and 8.2% for device with 100 μm gate width. The experimental results indicate that designing a reasonable structure is an effective method to enhance the radiation resistance in InP-based HEMTs, and this method can also be utilized in other semiconductor devices.

Effect of 1 MeV electron irradiation on gate contact characteristics of InP-based HEMTs

In this study, the variation of Schottky gate contact characteristics of InP-based HEMTs have been studied with the irradiation fluence range from 1 × 1014 cm-2 to 1 × 1016 cm-2 at 1 MeV. The results show that the reverse gate current increases with irradiation fluence, and the reason is that electrons would be released from the induced interface defects and pass through the Schottky barrier under reverse bias. Additionally, the forward gate current decreases and the series resistance of gate contact increases with electron fluence, because the carrier mobility and concentration should be deteriorated by the induced defects in bulk materials and surface state defects at contact interface. It is also found that the ideality factor n increases and the Schottky barrier height ΦB decreases with irradiation fluence, which can be attributed to the radiation induced interface defects at contact interface.

Surface Improvement of InAlAs/InGaAs InP-Based HEMT Through Treatments of UV/Ozone and TMAH

In this paper, we introduce novel surface treatments of UV/Ozone and TMAH to solve the surface problem of gate recess of InAlAs/InGaAs InP-based HEMTs. The problem of nonstoichiometric surface of InP etch stopper layer was found to be the result of donor-like surface defects brought by HF damage, bringing troubles like kink effect, high gate leakage current and deteriorated noise performance. Through the method of surface treatments, the InAlAs/InGaAs InP-based HEMTs exhibit excellent DC performances, demonstrating a low gate leakage currents of 10 -8 A/um, a peak transconductance of 1100mS/mm, an improved subthreshold swing of 92.5mV/decade at V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ds</sub> = 1.0V, and a positive threshold voltage shift of V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> = 300 mV. The ft of 260GHz and fmax of 440GHz were hardly influenced by the surface treatments while the noise performances were improved obviously. Two orders of magnitude smaller input noise spectral density shows the method of surface treatment can effectively reduce the surface defects and significantly improve the surface of gate recess of InAlAs/InGaAs InP-based HEMTs.

Characterization of InP-based pseudomorphic HEMT with T-gate

This paper proposes two structures of InAlAs/InGaAs-based pseudomorphic high electron mobility transistor (PHEMT): one with rectangular-gate and another with T-gate. Both the proposed PHEMTs consist of an In0.52Al0.48As supply/barrier layer and In0.53Ga0.47As channel layer built on an InP substrate. The proposed InAlAs/InGaAs-based PHEMT with rectangular-gate exhibits 1.32 × increment in drain current and 0.55 × decrement in threshold voltage compared to those of AlGaAs/GaAs-based previously proposed HEMT on GaAs substrate. This is because of the role of indium in the new materials used for the proposed device layers. The proposed InAlAs/InGaAs-based PHEMT with T-gate exhibits further improvements in DC and RF characteristics. The PHEMT with T-gate shows 1.42 ×/1.14 ×/1.4 × increment in drain current/cut-off frequency/maximum oscillation frequency respectively compared to the PHEMT with rectangular-gate. It also exhibits 0.67 × decrement in noise figure compared to that of PHEMT with rectangular-gate. All the theoretical results are verified with the simulation results obtained while analyzing the structures considered in this work. The simulation results were recorded while simulating the devices using Silvaco Atlas.

蝶形天线增强的InP基室温HEMT太赫兹探测器研究

蝶形天线增强的InP基室温HEMT太赫兹探测器研究

Improved DC and RF performance of InAlAs/InGaAs InP based HEMTs using ultra-thin 15 nm ALD-Al2O3 surface passivation

Owing to the great influence of surface passivation on DC and RF performance of InP-based HEMTs, the DC and RF performance of InAlAs/InGaAs InP HEMTs were studied before and after passivation, using an ultra-thin 15 nm atomic layer deposition Al2O3 layer. Increase in Cgs and Cgd was significantly limited by scaling the thickness of the Al2O3 layer. For verification, an analytical small-signal equivalent circuit model was developed. A significant increase in maximum transconductance (gm) up to 1150 mS/mm, drain current (IDS) up to 820 mA/mm and fmax up to 369.7 GHz was observed, after passivation. Good agreement was obtained between the measured and the simulated results. This shows that the RF performance of InP-based HEMTs can be improved by using an ultra-thin ALD-Al2O3 surface passivation.

Growth condition optimization and mobility enhancement through inserting AlAs monolayer in the InP-based InxGa1−xAs/In0.52Al0.48As HEMT structures**Project supported by the National Natural Science Foundation of China (Grant No. 61434006).

The structure of InP-based InxGa1−xAs/In0.52Al0.48As pseudomorphic high electron mobility transistor (PHEMT) was optimized in detail. Effects of growth temperature, growth interruption time, Si δ-doping condition, channel thickness and In content, and inserted AlAs monolayer (ML) on the two-dimensional electron gas (2DEG) performance were investigated carefully. It was found that the use of the inserted AlAs monolayer has an enhancement effect on the mobility due to the reduction of interface roughness and the suppression of Si movement. With optimization of the growth parameters, the structures composed of a 10 nm thick In0.75Ga0.25As channel layer and a 3 nm thick AlAs/In0.52Al0.48As superlattices spacer layer exhibited electron mobilities as high as 12500 cm2·V−1·s−1 (300 K) and 53500 cm2·V−1·s−1 (77 K) and the corresponding sheet carrier concentrations (Ns) of 2.8 × 1012 cm−2 and 2.9 × 1012 cm−2, respectively. To the best of the authors’ knowledge, this is the highest reported room temperature mobility for InP-based HEMTs with a spacer of 3 nm to date.

Studying on source/drain contact resistance reduction for InP-based HEMT

In this letter, Ti/Pt/Au metal system has been investigated for the source/drain contact of MHEMT, the Ti/Pt/Au contact exhibits good ohmic contact characteristics with well thermal stability in the temperature range from 280 to 340°C. To further optimize the contact resistance, different metal deposition methods and contact layers are experimentally investigated. With sputtering Pd as an interlayer between Ti/Pt/Au and n+-InGaAs, the specific contact resistivity is further reduced to 3.51 × 10−5 Ω cm2. Meanwhile, by adopting this metal contact system, the MHEMT shows good DC and RF characteristics, including full channel current of 75 mA/mm, extrinsic maximum transconductance gm.max of 96 ms/mm, unity current gain cutoff frequency fT of 60 GHz and maximum frequency of oscillation fmax of 156 GHz. These good electrical characteristics demonstrate that this metal contact system is beneficial for the performance improvement of MHEMT. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:217–221, 2016

Fabrication of a 120 nm gate-length lattice-matched InGaAs/InAlAs InP-based HEMT

A new PMMA/PMGI/ZEP520/PMGI four-layer resistor electron beam lithography technology is successfully developed and used to fabricate a 120 nm gate-length lattice-matched In0 53Ga0 47As/In0 52Al0 48As InP-based HEMT, of which the material structure is successfully designed and optimized by our group. A 980 nm ultra-wide T-gate head, which is nearly as wide as 8 times the gatefoot (120 nm), is successfully obtained, and the excellent T-gate profile greatly reduces the parasitic resistance and capacitance effect and effectively enhances the RF performances. These fabricated devices demonstrate excellent DC and RF performances such as a maximum current gain frequency of 190 GHz and a unilateral power-gain gain frequency of 146 GHz.

$W$-band Transmitter and Receiver for 10-Gb/s Impulse Radio With an Optical-Fiber Interface

A <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">W</i> -band millimeter-wave transmitter and receiver that are based on impulse radio (IR) architecture were developed. The IR-based apparatuses have an optical-fiber input/output interface board that supports multi protocol signals (OC-192 and 10 GbE) and that implements a forward error correction (FEC), enabling 10-Gb/s data transmission both in space and fiber seamlessly. Analyzing an IR-based receiver model with simple on/off demodulation architecture, required signal-to-noise ratios were calculated for IR-based systems affected by various inter-symbol interference (ISI) levels. A millimeter-wave module used in the transmitter, consisting of a 6.5-ps pulse modulator with InP-based HEMTs and a band-pass filter formed on an alumina substrate, emitted wavelets, or RF pulses, with an average power of -26 dBm, occupying frequencies between 78-93 GHz. A front-end module used in the receiver, consisting of two cascaded low-noise amplifiers, an envelope detector, and a limiting amplifier, had a sensitivity of -36 dBm. In a back-to-back test where the transmitter and receiver were connected by a waveguide, disabling the FEC, error-free operation was achieved with a test pattern of PRBS 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">31</sup> -1 at the OC-192 compliant data rate of 9.95328 Gb/s. Furthermore, using a horn antenna and enabling the FEC, radio transmission and reception in a distance of 20 cm were confirmed with a bit error rate of less than 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-12</sup> . These results confirmed the basic technologies for simple and compact IR-based systems, which could be used as an alternative to fiber optic cables.

InP-based HEMTs Suitable for Ultra-high-speed MMICs Fabrication

not Available.