Thermal Performance Improvement of AlGaN/GaN HEMTs Using Nanocrystalline Diamond Capping Layers

Guo, Hua; Li, Yizhuang; Yu, Xinxin; Zhou, Jianjun; Kong, Yuechan

doi:10.3390/mi13091486

Cited by 7 publications

(3 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[5][6][7] The problem is more severe at higher frequencies with low power gain. [8][9][10][11] Achieving a higher power density (7-10 W mm À1 ) reproducibly and reliably beyond 10 GHz is still challenging. [12][13][14] In addition, short channel effects (SCEs) tend to reduce the gain for smaller gate lengths meant to increase the operating frequency.…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Gate and SiC Substrate Grooved InGaN Back‐Barrier AlGaN/GaN HEMTs for High‐Power RF Applications

Parvez,

Sahu,

Basak

et al. 2024

Physica Status Solidi (a)

View full text Add to dashboard Cite

We report high‐power InGaN back‐barrier AlGaN/GaN high electron mobility transistors with the gate placed closer to the source with an Au‐filled groove in the SiC substrate near the drain end. An InGaN back‐barrier is known to reduce short‐channel effects at high drain‐to‐source (VDS) voltage. However, the improvement is realized at the cost of reduced two‐dimensional electron gas density (ns) and saturation drain‐to‐source (IDS,SAT) current. Here, we demonstrate that both ns and IDS,SAT are recovered when the gate is appropriately delineated near the source. The junction temperature increases at higher VDS, which tends to deteriorate the power performance and suppress the benefits from higher IDS,SAT. This problem is contained by further thinning down the SiC substrate near the drain by creating a backside groove using deep reactive‐ion‐etching and filling it with Ti/Au. An enhanced thinned‐down substrate distributes the lateral electric field uniformly near the drain end, compounding its benefits with an asymmetric gate and lower junction temperature. The proposed device shows an output power of Pout = 6.7 W mm−1 at VDS = 28 V at 15 GHz for a 200 nm gate length (LG).

show abstract

Section: Introductionmentioning

confidence: 99%

Asymmetric Gate and SiC Substrate Grooved InGaN Back‐Barrier AlGaN/GaN HEMTs for High‐Power RF Applications

Parvez,

Sahu,

Basak

et al. 2024

Physica Status Solidi (a)

View full text Add to dashboard Cite

show abstract

“…Previously, conventional face-up double gate fingers GaN HEMTs capped by a diamond heat spreader and a SiN passivation layer for RF application have been accomplished and discussed [ 11 ]. Thermal experiments show that thermal resistance of GaN HEMT with a diamond heat spreader layer is lower than traditional GaN HEMT with a SiN passivation layer by 21.4%.…”

Section: Introductionmentioning

confidence: 99%

Thermal Analysis of Flip-Chip Bonding Designs for GaN Power HEMTs with an On-Chip Heat-Spreading Layer

et al. 2023

View full text Add to dashboard Cite

In this work, we demonstrated the thermal analysis of different flip-chip bonding designs for high power GaN HEMT developed for power electronics applications, such as power converters or photonic driver applications, with large gate periphery and chip size, as well as an Au metal heat-spreading layer deposited on top of a planarized dielectric/passivation layer above the active region. The Au bump patterns can be designed with high flexibility to provide more efficient heat dissipation from the large GaN HEMT chips to an AlN package substrate heat sink with no constraint in the alignment between the HEMT cells and the thermal conduction bumps. Steady-state thermal simulations were conducted to study the channel temperatures of GaN HEMTs with various Au bump patterns at different levels of current and voltage loadings, and the results were compared with the conventional face-up GaN die bonding on an AlN package substrate. The simulations were started from a single finger isolated HEMT cell and then extended to multiple fingers HEMT cells (total gate width > 40 mm) to investigate the “thermal cross-talk” effect from neighboring devices. Thermal analysis of the GaN HEMT under pulse operation was also performed to better reflect the actual conditions in power conversion or pulsed laser driver applications. Our analysis provides a combinational assessment of power GaN HEMT dies under a working condition (e.g., 1MHz, 25% duty cycle) with different flip chip packaging schemes. The analysis indicated that the channel temperature rise (∆T) of a HEMT cell in operation can be reduced by 44~46% by changing from face-up die bonding to a flip-chip bonding scheme with an optimized bump pattern design.

show abstract

“…Owing to their high frequency and power handling potentialities, AlGaN/GaN high-electron-mobility transistors (HEMTs) are expected to play substantial roles in future satellite and information technologies [ 1 , 2 , 3 , 4 ]. The majority of the power of such devices is dissipated over relatively small areas of about 0.5–1 μm around the gate contact, resulting in local Joule self-heating [ 5 , 6 , 7 , 8 , 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

Explicit Thermal Resistance Model of Self-Heating Effects of AlGaN/GaN HEMTs with Linear and Non-Linear Thermal Conductivity

et al. 2022

View full text Add to dashboard Cite

We presented an explicit empirical model of the thermal resistance of AlGaN/GaN high-electron-mobility transistors on three distinct substrates, including sapphire, SiC, and Si. This model considered both a linear and non-linear thermal resistance model of AlGaN/GaN HEMT, the thickness of the host substrate layers, and the gate length and width. The non-linear nature of channel temperature—visible at the high-power dissipation stage—along with linear dependency, was constructed within a single equation. Comparisons with the channel temperature measurement procedure (DC) and charge-control-based device modeling were performed to verify the model’s validity, and the results were in favorable agreement with the observed model data, with only a 1.5% error rate compared to the measurement data. An agile expression for the channel temperature is also important for designing power devices and monolithic microwave integrated circuits. The suggested approach provides several techniques for investigation that could otherwise be impractical or unattainable when utilizing time-consuming numerical simulations.

show abstract

Thermal Performance Improvement of AlGaN/GaN HEMTs Using Nanocrystalline Diamond Capping Layers

Cited by 7 publications

References 19 publications

Asymmetric Gate and SiC Substrate Grooved InGaN Back‐Barrier AlGaN/GaN HEMTs for High‐Power RF Applications

Asymmetric Gate and SiC Substrate Grooved InGaN Back‐Barrier AlGaN/GaN HEMTs for High‐Power RF Applications

Thermal Analysis of Flip-Chip Bonding Designs for GaN Power HEMTs with an On-Chip Heat-Spreading Layer

Explicit Thermal Resistance Model of Self-Heating Effects of AlGaN/GaN HEMTs with Linear and Non-Linear Thermal Conductivity

Contact Info

Product

Resources

About