Microwave performance of ZnO/ZnMgO heterostructure field effect transistors

✍ Scribed by Sasa, Shigehiko ;Maitani, Takeshi ;Furuya, Yuto ;Amano, Takeshi ;Koike, Kazuto ;Yano, Mitsuaki ;Inoue, Masataka

• Book ID: 105366002
• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 509 KB
• Volume: 208
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.201000509

✦ Synopsis

Abstract

We report the first microwave performance of single crystalline ZnO/ZnMgO heterostructure field‐effect transistors (HFETs). The structure consisted of a 15‐nm‐thick ZnO channel layer was grown by molecular beam epitaxy (MBE) on an a‐sapphire substrate. Two‐finger type HFETs with 1 or 2‐µm‐long gate were fabricated and measured for microwave performance. The transconductance of the HFETs are 28 and 23 mS/mm for 1 and 2‐µm‐gate devices, respectively. The microwave measurement of ZnO‐based TFTs revealed that the current gain cutoff frequency f~T~ of 1.75 GHz and that of unilateral power gain f~max~ of 2.45 GHz for 1‐µm‐gate HFET. Electron velocity obtained by two‐terminal measurements implies that the structural design is crucial for further improvement of the high‐frequency performance of ZnO/ZnMgO HFETs.magnified image

Small‐signal microwave characteristics of a 1‐µm‐gate ZnO/ZnMgO heterostructure FET. The current gain cutoff frequency of 1.75 GHz and the unilateral power gain cutoff frequency of 2.45 GHz were obtained.