pith. sign in

arxiv: 2604.05106 · v1 · submitted 2026-04-06 · ⚛️ physics.app-ph · cond-mat.mtrl-sci

Temperature Dependent Characteristics of Quasi-vertical AlN Schottky Diodes on Bulk AlN Substrate

Md Abdul Hamid , Nabasindhu Das , Advait Gilankar , Brad Lenzen , David J. Smith , Nidhin Kurian Kalarickal This is my paper

Pith reviewed 2026-05-10 18:50 UTC · model grok-4.3

classification ⚛️ physics.app-ph cond-mat.mtrl-sci
keywords AlNSchottky barrier diodeshigh temperaturePoole-Frenkel emissionpower devicesbulk AlNMOCVDinterfacial layer
0
0 comments X

The pith

Quasi-vertical AlN Schottky diodes maintain stable rectification up to 300°C with leakage following Poole-Frenkel emission from 0.34 eV traps.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper reports fabrication and temperature-dependent electrical characterization of MOCVD-grown quasi-vertical AlN Schottky barrier diodes fabricated on bulk AlN substrates. It demonstrates that these devices deliver current densities above 2 kA/cm² at 10 V, turn-on voltages near 3 V, and on/off ratios exceeding 10^9 at room temperature while preserving rectifying behavior at 300°C. The work maps how carrier transport becomes thermally activated at higher temperatures, how net doping rises because silicon acts as a deep donor, and how reverse leakage is governed by Poole-Frenkel emission, all while noting the presence of a thin interfacial layer at the metal-semiconductor junction.

Core claim

Quasi-vertical AlN SBDs on bulk AlN substrates achieve current densities exceeding 2 kA/cm² at 10 V with a turn-on voltage of approximately 3.0 V and on/off ratios greater than 10^9 at room temperature. These diodes maintain stable rectifying operation up to 300°C, where current density increases due to thermally activated transport, the extracted Schottky barrier height rises, and the ideality factor falls. Capacitance-voltage data indicate that the net donor concentration rises with temperature because of the deep donor character of Si in AlN, while reverse-bias leakage follows Poole-Frenkel emission with an estimated trap energy of 0.34 eV; a 5 nm AlNxOy interfacial layer is present at a

What carries the argument

Temperature-dependent current-voltage and capacitance-voltage measurements that identify Poole-Frenkel emission as the dominant reverse leakage mechanism and the deep-donor ionization of silicon dopants as the source of temperature-dependent carrier concentration.

Load-bearing premise

The temperature dependence of capacitance and leakage can be fully attributed to the deep-donor nature of Si and Poole-Frenkel emission without significant contribution from other mechanisms or from the observed 5 nm interfacial layer altering the effective barrier.

What would settle it

A measurement showing that the reverse current does not follow the expected Poole-Frenkel field dependence or that the activation energy deviates significantly from 0.34 eV would challenge the leakage mechanism identification.

read the original abstract

We report on the fabrication and temperature-dependent characterization of MOCVD-grown quasi-vertical AlN Schottky barrier diodes (SBDs) on bulk AlN substrates. The SBDs exhibited high current densities exceeding 2 kA/cm2 at 10 V, with a turn-on voltage of ~3.0 V (at 1 A/cm^2) and an on/off ratio >10^9 at room temperature. Stable rectifying operation was maintained up to 300 C (the highest measured temperature), with a pronounced increase in current density at elevated temperatures due to thermally activated carrier transport, accompanied by an increase in extracted Schottky barrier height and a reduction in ideality factor. Capacitance voltage measurements showed strong temperature dependence due to the deep donor nature of Si in AlN, resulting in an increase in the net donor concentration (ND-NA) from ~5x10^17 cm-3 at 300 K to ~1x10^18 cm-3 at 373 K. Temperature-dependent reverse-bias characteristics were consistent with Poole-Frenkel emission as the dominant leakage mechanism, with an estimated trap energy of ~0.34 eV. Characterization using transmission electron microscopy and energy-dispersive X-ray spectroscopy revealed a ~5 nm AlNxOy interfacial layer at the metal/semiconductor junction, which likely influences both forward and reverse transport. These results provide insight into carrier transport, leakage mechanisms, interface chemistry, and high-temperature characteristics, and guidance for the future development of high-performance AlN power devices.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The manuscript reports fabrication and temperature-dependent I-V/C-V characterization of MOCVD-grown quasi-vertical AlN Schottky barrier diodes on bulk AlN. It claims current densities >2 kA/cm² at 10 V, turn-on voltage ~3.0 V (at 1 A/cm²), on/off ratio >10^9 at RT, stable rectification to 300 °C, ND-NA rising from ~5×10^17 to ~1×10^18 cm^{-3} (300–373 K) due to Si deep donors, reverse leakage consistent with Poole-Frenkel emission (trap energy ~0.34 eV), and a ~5 nm AlN_xO_y interfacial layer observed by TEM/EDX that likely influences transport.

Significance. If the mechanism assignments hold after addressing interface effects, the work supplies concrete high-temperature performance metrics and transport insights for AlN power devices, an area of growing interest for harsh-environment electronics. The explicit reporting of high current density, on/off ratio, and combined electrical-microscopy data provides useful benchmarks and guidance for future device development.

major comments (2)
  1. [Abstract and reverse-bias section] Abstract and reverse-bias leakage analysis: The central claim that temperature-dependent reverse leakage is dominated by Poole-Frenkel emission with a ~0.34 eV trap rests on standard PF plots and activation analysis. However, the ~5 nm AlN_xO_y interfacial layer (TEM/EDX) is explicitly noted to 'likely influence both forward and reverse transport,' yet no calculation of its tunneling probability, dielectric-constant effect on effective barrier, or fixed-charge contribution is provided to show that subtracting the layer leaves the PF signature and 0.34 eV value unchanged. This is load-bearing for the leakage-mechanism conclusion.
  2. [Capacitance-voltage measurements] C-V temperature-dependence section: The reported rise in ND-NA from ~5×10^17 cm^{-3} (300 K) to ~1×10^18 cm^{-3} (373 K) is assigned to the deep-donor behavior of Si. This interpretation requires that the interfacial layer's states or thickness variation with temperature do not contribute appreciably to the apparent doping trend; no such separation or sensitivity analysis is shown, nor are error bars or raw 1/C²-V plots supplied to quantify uncertainty in the extracted values.
minor comments (2)
  1. [Abstract] Abstract lacks any mention of error bars, number of devices measured, or explicit fitting procedures for ideality factor, barrier height, and trap energy; adding these would improve reproducibility.
  2. [Discussion or interface analysis] The manuscript would benefit from a brief quantitative estimate (even order-of-magnitude) of the interfacial layer's expected tunneling current or barrier modification to directly support the claim that bulk mechanisms remain dominant.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the positive evaluation of our work on quasi-vertical AlN Schottky diodes and for the constructive major comments. We address each point below with the strongest honest defense possible based on the data and analysis in the manuscript. Revisions will be made to improve clarity where the comments identify gaps.

read point-by-point responses

  1. Referee: The central claim that temperature-dependent reverse leakage is dominated by Poole-Frenkel emission with a ~0.34 eV trap rests on standard PF plots and activation analysis. However, the ~5 nm AlNxOy interfacial layer (TEM/EDX) is explicitly noted to 'likely influence both forward and reverse transport,' yet no calculation of its tunneling probability, dielectric-constant effect on effective barrier, or fixed-charge contribution is provided to show that subtracting the layer leaves the PF signature and 0.34 eV value unchanged. This is load-bearing for the leakage-mechanism conclusion.

    Authors: We agree that quantifying the interfacial layer's contribution would strengthen the conclusion. The observed PF plots remain linear across 300-573 K with a consistent 0.34 eV activation energy extracted from the temperature dependence of leakage current density, which is governed by bulk emission rather than the thin static layer. The 5 nm AlNxOy layer primarily affects the effective barrier in forward bias, as separately analyzed. In revision we will add a WKB-based estimate of tunneling probability through the layer (using its measured thickness and approximate dielectric constant from EDX) and discuss why it does not alter the dominant PF signature or extracted trap energy. We will also note the analysis limitations. revision: partial

  2. Referee: The reported rise in ND-NA from ~5×10^17 cm^{-3} (300 K) to ~1×10^18 cm^{-3} (373 K) is assigned to the deep-donor behavior of Si. This interpretation requires that the interfacial layer's states or thickness variation with temperature do not contribute appreciably to the apparent doping trend; no such separation or sensitivity analysis is shown, nor are error bars or raw 1/C²-V plots supplied to quantify uncertainty in the extracted values.

    Authors: The doubling of ND-NA with temperature aligns with the known ~0.2-0.3 eV deep donor level of Si in AlN, where higher temperature ionizes more donors as the Fermi level shifts. Measurements were taken at 1 MHz to suppress slow interface trap response. In the revised manuscript we will include the raw 1/C²-V plots, add error bars derived from linear regression uncertainty on each 1/C²-V fit, and provide a sensitivity analysis demonstrating that plausible temperature-induced changes in the 5 nm layer (e.g., ±1 nm thickness or fixed charge) cannot account for the observed factor-of-two increase in ND-NA. This will reinforce the Si deep-donor assignment. revision: yes

Circularity Check

0 steps flagged

No circularity: purely experimental parameter extraction from measured I-V/C-V data using standard equations

full rationale

The paper is an experimental characterization study reporting fabrication of quasi-vertical AlN SBDs, temperature-dependent I-V and C-V measurements, and extraction of quantities (turn-on voltage, barrier height, ideality factor, ND-NA, trap energy ~0.34 eV) via direct application of textbook semiconductor relations (e.g., thermionic emission, Poole-Frenkel model, Mott-Schottky analysis) to the raw data. No self-definitional loops, fitted inputs relabeled as predictions, load-bearing self-citations, uniqueness theorems, or ansatzes imported from prior author work appear. The ~5 nm interfacial layer is noted as likely influential but is not incorporated into any derivation that would create circularity; the central claims remain independent of any internal redefinition. The chain is self-contained against external benchmarks.

Axiom & Free-Parameter Ledger

2 free parameters · 2 axioms · 0 invented entities

The central claims rest on standard semiconductor-physics models for Schottky transport and Poole-Frenkel emission plus the assumption that the observed interfacial layer is the primary non-ideality source; no new entities are postulated.

free parameters (2)
  • trap energy = 0.34 eV
    Fitted value of ~0.34 eV extracted from temperature-dependent reverse leakage assuming Poole-Frenkel emission dominates.
  • net donor concentration at 300 K = 5x10^17 cm-3
    Extracted from C-V data and reported as ~5x10^17 cm-3.
axioms (2)
  • domain assumption Poole-Frenkel emission is the dominant reverse-bias leakage mechanism
    Invoked to interpret temperature-dependent reverse I-V data and to extract the 0.34 eV trap energy.
  • domain assumption Si acts as a deep donor whose ionization changes with temperature
    Used to explain the observed increase in ND-NA between 300 K and 373 K.

pith-pipeline@v0.9.0 · 5609 in / 1725 out tokens · 33713 ms · 2026-05-10T18:50:02.192794+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Lean theorems connected to this paper

Citations machine-checked in the Pith Canon. Every link opens the source theorem in the public Lean library.

What do these tags mean?
matches
The paper's claim is directly supported by a theorem in the formal canon.
supports
The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
extends
The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
uses
The paper appears to rely on the theorem as machinery.
contradicts
The paper's claim conflicts with a theorem or certificate in the canon.
unclear
Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.

Reference graph

Works this paper leans on

4 extracted references · 4 canonical work pages

  1. [1]

    Electron mobility in AlN from first principles,

    1 A. Wang, N. Pant, W. Lee, J.-C. Chen, F. Giustino, and E. Kioupakis, “Electron mobility in AlN from first principles,” Appl. Phys. Lett. 127(7), 072110 (2025). 2 C. Perez, A.J. McLeod, M.E. Chen, S. Yi, S. Vaziri, R. Hood, S.T. Ueda, X. Bao, M. Asheghi, W. Park, A.A. Talin, S. Kumar, E. Pop, A.C. Kummel, and K.E. Goodson, “High Thermal Conductivity of S...

    work page 2025

  2. [2]

    Deep- Ultraviolet AlN Metalens with Imaging and Ultrafast Laser Microfabrication Applications,

    Duh, B.-R. Lee, C.-Y . Huang, M.-H. Shih, R.-H. Horng, K. Konishi, and M.L. Tseng, “Deep- Ultraviolet AlN Metalens with Imaging and Ultrafast Laser Microfabrication Applications,” Nano Lett. 25(8), 3141–3149 (2025). 10 W. Sun, C.-K. Tan, and N. Tansu, “AlN/GaN Digital Alloy for Mid- and Deep-Ultraviolet Optoelectronics,” Sci Rep 7(1), 11826 (2017). 11 Q. ...

    work page 2025

  3. [3]

    High-current, high-voltage AlN Schottky barrier diodes,

    Kirste, S. Pavlidis, E. Kohn, R. Collazo, and Z. Sitar, “High-current, high-voltage AlN Schottky barrier diodes,” Appl. Phys. Express 17(10), 101002 (2024). 13 C. Hartmann, A. Dittmar, J. Wollweber, and M. Bickermann, “Bulk AlN growth by physical vapour transport,” Semicond. Sci. Technol. 29(8), 084002 (2014). 14 S. Hasan, A. Mamun, K. Hussain, D. Patel, ...

    work page 2024

  4. [4]

    High-current, high-voltage AlN Schottky barrier diodes,

    Kirste, S. Pavlidis, E. Kohn, R. Collazo, and Z. Sitar, “High-current, high-voltage AlN Schottky barrier diodes,” Appl. Phys. Express 17(10), 101002 (2024). 18 H. Cao, M. Nong, T. Liu, G.I. García, Z. Liu, X. Tang, M. Kumar, B. Sarkar, Y . Wu, and X. Li, “Performance Enhancement of n-Type AlN Schottky Barrier Diodes Using Oxygen-Rich Rapid Thermal Anneali...

    work page 2024