The Role of Carbon Doping on Breakdown, Current Collapse, and Dynamic On‐Resistance Recovery in AlGaN/GaN High Electron Mobility Transistors on Semi‐Insulating SiC Substrates

Zagni, Nicolò; Chini, Alessandro; Puglisi, Francesco Maria; Pavan, Paolo; Verzellesi, Giovanni

doi:10.1002/pssa.201900762

Cited by 15 publications

(10 citation statements)

References 17 publications

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“…Calibration of the simulation parameters against measurements taken from [ 1 ] has already been reported in [ 14 , 17 ]. What makes the measurements reported in [ 1 ] instrumental to our scope is the possibility of calibrating our simulation deck against a consistent set of experimental data from devices with several different L GD values.…”

Section: Modeling Frameworkmentioning

confidence: 99%

“… Calibrated pulsed I D – V DS curve simulations (lines) showing the achieved agreement in current-collapse measurements from [ 1 ] (symbols). Adapted from [ 17 ]. …”

Section: Figurementioning

confidence: 99%

“…These aspects call for the correct modeling of C-related trap states in GaN transistors when performing device simulations to investigate important performance-limiting effects, such as buffer leakage and related V BD [ 13 , 14 ], dynamic R ON [ 4 , 10 , 16 ], current collapse [ 2 , 12 , 17 ], and threshold voltage instabilities [ 18 , 19 , 20 , 21 ]. In fact, both the concentration of acceptor states ( N C,A ) and donor states ( N C,D ), as well as their compensation ratio , defined as CR = N C,D / N C,A , need to be properly determined in order to reproduce the features of realistic devices and calibrate device simulation for a given technology.…”

Section: Introductionmentioning

confidence: 99%

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On the Modeling of the Donor/Acceptor Compensation Ratio in Carbon-Doped GaN to Univocally Reproduce Breakdown Voltage and Current Collapse in Lateral GaN Power HEMTs

et al. 2021

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The intentional doping of lateral GaN power high electron mobility transistors (HEMTs) with carbon (C) impurities is a common technique to reduce buffer conductivity and increase breakdown voltage. Due to the introduction of trap levels in the GaN bandgap, it is well known that these impurities give rise to dispersion, leading to the so-called “current collapse” as a collateral effect. Moreover, first-principles calculations and experimental evidence point out that C introduces trap levels of both acceptor and donor types. Here, we report on the modeling of the donor/acceptor compensation ratio (CR), that is, the ratio between the density of donors and acceptors associated with C doping, to consistently and univocally reproduce experimental breakdown voltage (VBD) and current-collapse magnitude (ΔICC). By means of calibrated numerical device simulations, we confirm that ΔICC is controlled by the effective trap concentration (i.e., the difference between the acceptor and donor densities), but we show that it is the total trap concentration (i.e., the sum of acceptor and donor densities) that determines VBD, such that a significant CR of at least 50% (depending on the technology) must be assumed to explain both phenomena quantitatively. The results presented in this work contribute to clarifying several previous reports, and are helpful to device engineers interested in modeling C-doped lateral GaN power HEMTs.

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Section: Modeling Frameworkmentioning

confidence: 99%

“… Calibrated pulsed I D – V DS curve simulations (lines) showing the achieved agreement in current-collapse measurements from [ 1 ] (symbols). Adapted from [ 17 ]. …”

Section: Figurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the Modeling of the Donor/Acceptor Compensation Ratio in Carbon-Doped GaN to Univocally Reproduce Breakdown Voltage and Current Collapse in Lateral GaN Power HEMTs

et al. 2021

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“…The above C doping model was adopted since it allowed us to reproduce current-collapse and breakdown effects in different GaN power HEMTs yielding an acceptable agreement with experimental results [27][28][29][30][31][32][33]. The key feature of this model is that dominant, deep, acceptor-type, hole traps are partially compensated by shallow, donor-type, electron traps.…”

Section: Modeling Frameworkmentioning

confidence: 99%

The effects of carbon on the bidirectional threshold voltage instabilities induced by negative gate bias stress in GaN MIS-HEMTs

et al. 2020

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In this paper, numerical device simulations are used to point out the possible contributions of Carbon doping to the threshold voltage instabilities induced by negative gate bias stress in AlGaN/GaN Metal Insulator Semiconductor High Electron Mobility Transistors (MIS-HEMTs). It is suggested that Carbon can have a role in both negative and positive threshold voltage shifts, as a result of the changes in the total negative charge stored in the Carbon-related acceptor traps in the GaN buffer as well as the attraction of Carbon-related free holes to the device surface and their capture into interface traps or recombination with gate-injected electrons. For a proper device optimization of Carbon-doped MIS-HEMTs, it is therefore important to take these mechanisms into account, in addition to those related to defects in the gate dielectric volume and interface which are conventionally held responsible for threshold voltage instabilities.

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“…Such charges can be located either in a 2-DHG or at shallow traps [14,15]. On the other hand, the negative charge release leading to the subsequent slow current increase is thermally activated, since it involves by multi-phonon emission from a deep level (CN) [23].…”

Section: Pulsed Drain Current Transientmentioning

confidence: 99%

OFF-state trapping phenomena in GaN HEMTs: Interplay between gate trapping, acceptor ionization and positive charge redistribution

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Meneghini

Santi

et al. 2020

Microelectronics Reliability

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We present an extensive analysis of the trapping processes induced by drain bias stress in AlGaN/GaN highelectron-mobility transistors (HEMTs) with p-GaN gate. We demonstrate that: (i) with increasing drain stress, pulsed I-V and VTH measurements shown an initial positive VTH variation and an increase in RON then, for drain voltages >100 V, VTH is stable and the RON shows a partial recovery. (ii) At moderate voltages, VTH instability is related to trapping at the gate stack, due to residual negative charge left behind by the holes that leave the p-GaN layer through the Schottky gate contact and/or to trapping at the barrier. At higher voltages, we demonstrate the interplay of two trapping processes by C-V and pulsed drain current analysis: (iii) a fast storage of positive charge, accumulated near the buffer/SRL interface, not strongly thermally activated, dominating at higher voltages; (iv) a slower negative charge storage, thermally activated with activation energies for trapping and de-trapping equal to ~0.6 eV and ~0.4-0.8 eV, respectively.

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The Role of Carbon Doping on Breakdown, Current Collapse, and Dynamic On‐Resistance Recovery in AlGaN/GaN High Electron Mobility Transistors on Semi‐Insulating SiC Substrates

Cited by 15 publications

References 17 publications

On the Modeling of the Donor/Acceptor Compensation Ratio in Carbon-Doped GaN to Univocally Reproduce Breakdown Voltage and Current Collapse in Lateral GaN Power HEMTs

On the Modeling of the Donor/Acceptor Compensation Ratio in Carbon-Doped GaN to Univocally Reproduce Breakdown Voltage and Current Collapse in Lateral GaN Power HEMTs

The effects of carbon on the bidirectional threshold voltage instabilities induced by negative gate bias stress in GaN MIS-HEMTs

OFF-state trapping phenomena in GaN HEMTs: Interplay between gate trapping, acceptor ionization and positive charge redistribution

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