Nagoya University · 물리·천문학
Takeru Kumabe 교수의 연구실은 고성능 nitride 계 반도체 소자, 특히 AlGaN/GaN 기반의 고전류 밀도 및 고효율 전자소자를 목표로 하며, 분포형 전하 이동도(전기적 분극)를 이용한 독창적 도핑 기술(DPD: Distributed Polarization Doping)을 핵심으로 연구를 진행하고 있습니다. 특히 도핑 원자 없이도 안정적이고 높은 수준의 수동성과 전하 수송 특성을 확보한 '도핑 불필요(p-dopant-free)' p형 AlGaN 층의 구현과, 이를 응용한 HBT, p-n 접합, 전자소자에서의 소자 특성 향상에 중점을 두고 있습니다. ICP-RIE 등 밀도 높은 공정 손상 최소화 기술과 깊이 분석 기반의 광물성 분석을 융합하여, 고신뢰성 소자 설계 기반을 마련하고 있습니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
Nearly ideal vertical Al <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\textit{x}}$</tex-math> </inline-formula> Ga <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text{1}-\textit{x}}$</tex-math> </inline-formula> N ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xl
Abstract Inductively coupled plasma–reactive ion etching (ICP–RIE)-induced damage in heavily Mg-doped p-type GaN ([Mg] = 2 × 10 19 cm −3 ) was investigated by low-temperature photoluminescence (PL) and depth-resolved cathodoluminescence (CL) spectroscopy. From PL measurements, we found broad yellow luminescence (YL) with a maximum at around 2.2–2.3 eV, whose origin was considered to be isolated nitrogen vacancies ( V N ), only in etched samples. The depth-resolved CL spectroscopy revealed that t
Abstract An AlGaN/GaN heterojunction bipolar transistor (HBT) with N-p-n configuration was fabricated by the “regrowth-free” method, resulting in a contamination-free emitter-base AlGaN/GaN heterojunction. The low-bias-power-based low-damage inductively coupled plasma–reactive ion etching was employed in this study for emitter mesa definition instead of the conventional selective-area-regrowth technique. The method successfully minimized the etching-induced damage in the p-GaN base layer and the
Herein, the operation of dopant‐free GaN‐based p‐n junctions formed by distributed polarization doping (DPD) is experimentally demonstrated and their space charge profiles and carrier transport properties are investigated. The device exhibits ideal space charge profiles explained by polarization effects and demonstrates the excellent controllability of DPD. In addition, it shows rectification and electroluminescence under forward‐biased conditions. The carrier transport properties could be expla
We investigated the hole mobility limiting factors in dopant-free p-type distributed polarization-doped (DPD) AlGaN layers by an experimental method. p-DPD AlGaN exhibited a higher hole mobility than GaN:Mg with a similar room temperature hole concentration across all temperature ranges owing to the absence of ionized impurity scattering. In addition, unlike in n-DPD AlGaN, alloy scattering was not always critical in p-DPD AlGaN. The extracted alloy scattering potential was only 0.3 eV, which re
Minority carrier properties in dopant-free p-type distributed polarization doped (DPD) AlGaN layers were investigated on the basis of the forward-biased current density–voltage (J–V) characteristics of p–n+ diodes. The fabricated p-DPD AlGaN/n+–AlGaN:Si diodes exhibited ideal electrical characteristics despite the absence of acceptor atoms in the p-type layer. The extracted Shockley–Read–Hall lifetime exceeded 300 ps, which was longer than that reported for p-GaN:Mg on GaN substrates with a simi
Nearly ideal vertical AlGaN ( <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" alttext="0.7\ \leq x<1.0" display="inline"><m:mrow><m:mn>0</m:mn><m:mo>.</m:mo><m:mn>7</m:mn><m:mspace width="5.0pt" /><m:mo>≤</m:mo><m:mi>x</m:mi><m:mo><</m:mo><m:mn>1</m:mn><m:mo>.</m:mo><m:mn>0</m:mn></m:mrow></m:math> ) p-n diodes are fabricated on an AlN substrate. Distributed polarization doping (DPD) was employed for both p-type and n-type layers of the p-n junction, instead of conventional impurity d
Nearly ideal vertical AlxGa1-xN (\(0.7\ \le x<1.0\)) p-n diodes are fabricated on an AlN substrate. Distributed polarization doping (DPD) was employed for both p-type and n-type layers of the p-n junction, instead of conventional impurity doping, to overcome the major bottleneck of AlN-based material: the control of conductivity. Capacitance-voltage measurements revealed that the net charge concentration agreed well with the DPD charge concentration expected from the device layer structure. The
