scholarly journals 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

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 709
Author(s):  
Nicolò Zagni ◽  
Alessandro Chini ◽  
Francesco Maria Puglisi ◽  
Paolo Pavan ◽  
Giovanni Verzellesi

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.

2008 ◽  
Vol 600-603 ◽  
pp. 1345-1348 ◽  
Author(s):  
Akira Nakajima ◽  
Shuichi Yagi ◽  
Mitsuaki Shimizu ◽  
Hajime Okumura

The effect of AlGaN surface traps on breakdown voltage VB and drain current collapse in AlGaN/GaN high electron mobility transistors (HEMTs) were investigated using experimental measurement and numerical simulation. The drain current transient due to surface traps was systematically measured and analyzed, and the activation energy of a surface trap was evaluated as approximately 0.7 eV. Results from the device simulation of VB in HEMTs were in good agreement with the experimental results when assuming surface traps. The results indicate that surface traps increase VB, and induce a crucial current collapse.


2003 ◽  
Vol 764 ◽  
Author(s):  
B. Luo ◽  
F. Ren ◽  
M. A. Mastro ◽  
D. Tsvetkov ◽  
A. Pechnikov ◽  
...  

AbstractHigh quality undoped AlGaN/GaN high electron mobility transistors(HEMTs) structures have been gorwn by Hydride Vapor Phase Epitaxy (HVPE). The morphology of the films grown on Al2O3 substrates is excellent with root-mean-square roughness of ∼0.2nm over 10×10μm2 measurement area. Capacitance-voltage measurements show formation of dense sheet of charge at the AlGaN/GaN interface. HEMTs with 1μm gate length fabricated on these structures show transconductances in excess of 110 mS/mm and drain-source current above 0.6A/mm. Gate lag measurements show similar current collapse characteristics to HEMTs fabricated in MBE- or MOCVD grown material.


2011 ◽  
Vol 1324 ◽  
Author(s):  
Takuma Nanjo ◽  
Misaichi Takeuchi ◽  
Akifumi Imai ◽  
Yousuke Suzuki ◽  
Muneyoshi Suita ◽  
...  

ABSTRACTA channel layer substitution of a wider bandgap AlGaN for a conventional GaN in high electron mobility transistors (HEMTs) is an effective method of enhancing the breakdown voltage. Wider bandgap AlGaN, however, should also increase the ohmic contact resistance. Si ion implantation doping technique was utilized to achieve sufficiently low resistive source/drain contacts. The fabricated AlGaN channel HEMTs with the field plate structure demonstrated good pinch-off operation with sufficiently high drain current density of 0.5 A/mm without noticeable current collapse. The obtained maximum breakdown voltages was 1700 V in the AlGaN channel HEMT with the gate-drain distance of 10 μm. These remarkable results indicate that AlGaN channel HEMTs could become future strong candidates for not only high-frequency devices such as low noise amplifiers but also high-power devices such as switching applications.


2014 ◽  
Vol 7 (9) ◽  
pp. 096501 ◽  
Author(s):  
Kengo Kobayashi ◽  
Shinya Hatakeyama ◽  
Tomohiro Yoshida ◽  
Yuhei Yabe ◽  
Daniel Piedra ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document