RF Dielectric Loss Due to MOCVD Aluminum Nitride on High Resistivity Silicon

Berber, Feyza; Johnson, Derek W.; Sundqvist, K. M.; Piner, Edwin L.; Huff, Gregory H.; Harris, H. R.

doi:10.1109/tmtt.2017.2656865

Cited by 20 publications

(12 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Radiation losses being negligible in the probed frequency range, 34 attenuations during signal propagation on such metaldielectric waveguides primarily originate from the nonideality of the materials in the form of dielectric loss and conductor loss. The latter is known to be the dominant factor at <1 GHz and is controlled by surface resistivity and line inductivity, which should be similar for all of the identically deposited metallic lines.…”

Section: Acs Applied Electronic Materialsmentioning

confidence: 99%

“…27,29,32 Arguments negating the role of the substrate also exist, with the AlN nucleation layer itself held accountable for being conductive. 34 Irrespective of the origin, the presence of a capacitively coupled buried channel greatly undermines the potential of GaN HEMTs by inducing power loss not only for the transistors but also for the passive components and the connecting transmission lines of the integrated circuits (ICs); for example, investigations on structures grown by molecular beam epitaxy (MBE) process have identified that controlling the epi/ substrate interface is essential to minimize parasitic conduction and radio frequency (RF) loss. 35,36 Given the superior growth rates and wafer throughput but also the different thermodynamics and reaction kinetics of the MOVPE technique, understanding and controlling the physical origin of the parasitic conduction path in MOVPE-grown structures have become important to the demonstration and large-scale production of high-performance GaN-on-Si RF electronics.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Origin(s) of Anomalous Substrate Conduction in MOVPE-Grown GaN HEMTs on Highly Resistive Silicon

Ghosh

Hinz

Fairclough

et al. 2021

ACS Appl. Electron. Mater.

View full text Add to dashboard Cite

The performance of transistors designed specifically for high-frequency applications is critically reliant upon the semiinsulating electrical properties of the substrate. The suspected formation of a conductive path for radio frequency (RF) signals in the highly resistive (HR) silicon substrate itself has been long held responsible for the suboptimal efficiency of as-grown GaN high electron mobility transistors (HEMTs) at higher operating frequencies. Here, we reveal that not one but two discrete channels distinguishable by their carrier type, spatial extent, and origin within the metal-organic vapor phase epitaxy (MOVPE) growth process participate in such parasitic substrate conduction. An ntype layer that forms first is uniformly distributed in the substrate, and it has a purely thermal origin. Alongside this, a p-type layer is localized on the substrate side of the AlN/Si interface and is induced by diffusion of group-III element of the metal-organic precursor. Fortunately, maintaining the sheet resistance of this p-type layer to high values (∼2000 Ω/□) seems feasible with particular durations of either organometallic precursor or ammonia gas predose of the Si surface, i.e., the intentional introduction of one chemical precursor just before nucleation. It is proposed that the mechanism behind the control actually relies on the formation of disordered AlSiN between the crystalline AlN nucleation layer and the crystalline silicon substrate.

show abstract

Section: Acs Applied Electronic Materialsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Origin(s) of Anomalous Substrate Conduction in MOVPE-Grown GaN HEMTs on Highly Resistive Silicon

Ghosh

Hinz

Fairclough

et al. 2021

ACS Appl. Electron. Mater.

View full text Add to dashboard Cite

show abstract

“…Not only the use of high-resistivity substrates is necessary 2 , but also the achievement of both sufficient crystal quality and electrical resistivity of AlN/Si interface is required. Different phenomena have been reported as possible origins of parasitic conductivity and propagation losses: the diffusion of dopant species into the Si substrate 3 – 5 , the formation of an inversion layer at the AlN/Si interface 6 – 9 as well as degraded crystal quality 7 , 10 . In this context, the combination of several techniques is necessary to know the composition of the interface and its electrical behavior.…”

Section: Introductionmentioning

confidence: 99%

Electrical activity at the AlN/Si Interface: identifying the main origin of propagation losses in GaN-on-Si devices at microwave frequencies

Bah

Valente

Lesecq

et al. 2020

Sci Rep

View full text Add to dashboard Cite

AlN nucleation layers are the basement of GaN-on-Si structures grown for light-emitting diodes, high frequency telecommunication and power switching systems. In this context, our work aims to understand the origin of propagation losses in GaN-on-Si High Electron Mobility Transistors at microwaves frequencies, which are critical for efficient devices and circuits. AlN/Si structures are grown by Metalorganic Vapor Phase Epitaxy. Acceptor dopant in-diffusion (Al and Ga) into the Si substrate is studied by Secondary Ion Mass Spectroscopy and is mainly located in the first 200 nm beneath the interface. In this region, an acceptor concentration of a few 10 18 cm -3 is estimated from Capacitance–Voltage (C–V) measurements while the volume hole concentration of several 10 17 cm -3 is deduced from sheet resistance. Furthermore, the combination of scanning capacitance microscopy and scanning spreading resistance microscopy enables the 2D profiling of both the p -type conductive channel and the space charge region beneath the AlN/Si interface. We demonstrate that samples grown at lower temperature exhibit a p -doped conductive channel over a shallower depth which explains lower propagation losses in comparison with those synthesized at higher temperature. Our work highlights that this p -type channel can increase the propagation losses in the high-frequency devices but also that a memory effect associated with the previous sample growths with GaN can noticeably affect the physical properties in absence of proper reactor preparation. Hence, monitoring the acceptor dopant in-diffusion beneath the AlN/Si interface is crucial for achieving efficient GaN-on-Si microwave power devices.

show abstract

“…To test the RF loss of the epitaxial materials, the conductive part of the HEMT device needs to be removed, leaving only the buffer layer, and the CPW electrodes are fabricated directly on the buffer layer, as shown in Figure 1b. The S 21 of the CPW is usually used to characterize the RF loss of the buffer layer [19,20]. We used Silvaco to establish the CPW transmission line model.…”

Section: Structure Descriptionmentioning

confidence: 99%

Reduction in RF Loss Based on AlGaN Back-Barrier Structure Changes

et al. 2022

View full text Add to dashboard Cite

We designed a high electron mobility transistor (HEMT) epitaxial structure based on an AlGaN/GaN heterojunction, utilizing Silvaco TCAD, and selected AlGaN with an aluminum composition of 0.1 as the back-barrier of the AlGaN/GaN heterojunction. We enhanced the confinement of the two-dimensional electron gas (2DEG) by optimizing the structural parameters of the back barrier, so that the leakage current of the buffer layer is reduced. Through these optimization methods, a lower drain leakage current and a good radio frequency performance were obtained. The device has a cut-off frequency of 48.9 GHz, a maximum oscillation frequency of 73.20 GHz, and a radio frequency loss of 0.239 dB/mm (at 6 GHz). This work provides a basis for the preparation of radio frequency devices with excellent frequency characteristics and low RF loss.

show abstract

RF Dielectric Loss Due to MOCVD Aluminum Nitride on High Resistivity Silicon

Cited by 20 publications

References 27 publications

Origin(s) of Anomalous Substrate Conduction in MOVPE-Grown GaN HEMTs on Highly Resistive Silicon

Origin(s) of Anomalous Substrate Conduction in MOVPE-Grown GaN HEMTs on Highly Resistive Silicon

Electrical activity at the AlN/Si Interface: identifying the main origin of propagation losses in GaN-on-Si devices at microwave frequencies

Reduction in RF Loss Based on AlGaN Back-Barrier Structure Changes

Contact Info

Product

Resources

About