naa a22 4500 51080067X CHVBK 20180411083353.0 cr unu---uuuuu 180411e20130101xx s 000 0 eng 10.1007/s11664-012-2109-3 doi (NATIONALLICENCE)springer-10.1007/s11664-012-2109-3 Polarization-Engineered Ga-Face GaN-Based Heterostructures for Normally-Off Heterostructure Field-Effect Transistors [Elektronische Daten] [Hyeongnam Kim, Digbijoy Nath, Siddharth Rajan, Wu Lu] Polarization-engineered Ga-face GaN-based heterostructures with a GaN cap layer and an AlGaN/p-GaN back barrier have been designed for normally-off field-effect transistors (FETs). The simulation results show that an unintentionally doped GaN cap and p-GaN layer in the buffer primarily deplete electrons in the channel and the Al0.2Ga0.8N back barrier helps to pinch off the channel. Experimentally, we have demonstrated a normally-off GaN-based field-effect transistor on the designed GaN cap/Al0.3Ga0.7N/GaN channel/Al0.2Ga0.8N/p-GaN/GaN heterostructure. A positive threshold voltage of 0.2V and maximum transconductance of 2.6mS/mm were achieved for 80-μm-long gate devices. The device fabrication process does not require a dry etching process for gate recessing, while highly selective etching of the GaN cap against a very thin Al0.3GaN0.7N top barrier has to be performed to create a two-dimensional electron gas for both the ohmic and access regions. A self-aligned, selective etch of the GaN cap in the access region is introduced, using the gate metal as an etch mask. The absence of gate recess etching is promising for uniform and repeatable threshold voltage control in normally-off AlGaN/GaN heterostructure FETs for power switching applications. TMS, 2012 Normally-off III-nitride heterostructures nationallicence polarization engineering nationallicence selective etching nationallicence GaN cap nationallicence AlGaN/ p -GaN back barrier nationallicence Kim Hyeongnam Department of Electrical and Computer Engineering, The Ohio State University, 43210, Columbus, OH, USA aut Nath Digbijoy Department of Electrical and Computer Engineering, The Ohio State University, 43210, Columbus, OH, USA aut Rajan Siddharth Department of Electrical and Computer Engineering, The Ohio State University, 43210, Columbus, OH, USA aut Lu Wu Department of Electrical and Computer Engineering, The Ohio State University, 43210, Columbus, OH, USA aut Journal of Electronic Materials Springer US; http://www.springer-ny.com 42/1(2013-01-01), 10-14 0361-5235 42:1<10 2013 42 11664 https://doi.org/10.1007/s11664-012-2109-3 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11664-012-2109-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kim Hyeongnam Department of Electrical and Computer Engineering, The Ohio State University, 43210, Columbus, OH, USA aut NATIONALLICENCE 700 1- Nath Digbijoy Department of Electrical and Computer Engineering, The Ohio State University, 43210, Columbus, OH, USA aut NATIONALLICENCE 700 1- Rajan Siddharth Department of Electrical and Computer Engineering, The Ohio State University, 43210, Columbus, OH, USA aut NATIONALLICENCE 700 1- Lu Wu Department of Electrical and Computer Engineering, The Ohio State University, 43210, Columbus, OH, USA aut NATIONALLICENCE 773 0- Journal of Electronic Materials Springer US; http://www.springer-ny.com 42/1(2013-01-01), 10-14 0361-5235 42:1<10 2013 42 11664 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer