Impact of ZnO gate interfacial layer on piezoelectric response of AlGaN/GaN C-HEMT based ring gate capacitor

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• 作者：T.  ; Lalinsk&yacute ; ^a ; G.  ; Vanko^a ; M.  ; Vallo^a ;   ; ^{eleklali@savba.sk} ; M.  ; Dr?í ; k^b ; J.  ; Bruncko^b ; J.  ; Jakovenko^c ; V.  ; Kuti&scaron ; ^d ; I.  ; R&yacute ; ger^a ; &Scaron ; .  ; Ha&scaron ; ?í ; k^a ; M.  ; Husá ; k^c[Author vitae]
• 关键词：Stress sensor ; Dynamical stress ; AlGaN/GaN ; Circular-HEMT ; Piezoelectric response ; ZnO ; SiC
• 刊名：Sensors and Actuators A: Physical
• 出版年：2011
• 出版时间：December 2011
• 年：2011
• 卷：172
• 期：2
• 页码：386-391
• 全文大小：817 K

文摘

We report on a piezoelectric response investigation of AlGaN/GaN circular high electron mobility transistor (C-HEMT) based ring gate capacitor as a new stress sensor device to be potentially applied for dynamic high-pressure sensing. A ring gate capacitor of C-HEMT with an additional ZnO gate interfacial layer was used to measure the changes in the piezoelectric charge induced directly by the variation of piezoelectric polarization of both gate piezoelectric layers (AlGaN, ZnO) for harmonic loading at different excitation frequences. Our experimental results show that about 10 nm thick piezoelectric ZnO layer grown on ring gate/AlGaN interface of C-HEMT can yield almost a 60 % increase in the piezoelectric detection sensitivity of the device due to its higher piezoelectric coefficient. A three-dimensional CoventorWare simulation is carried out to confirm the increase in the measured piezoelectric response of ZnO based ring gate capacitor of C-HEMT.