We show that AlN-based piezocapacitors with relatively high piezoelectric coefficient (d(33)) values (3-4 pC/N) can be fabricated on polyimide (PI) substrates at 160 degrees C or even at room temperature by sputtering processes. With respect to PI, a reduction of the piezoelectric performances was observed on polyethylene naphthalate (PEN). With the same approach, a d(33) value as high as 8 pC/N was achieved on rigid substrates (SiO2/Si). In all cases, a thin Al buffer layer was deposited, immediately before AlN, without breaking the vacuum in the deposition chamber, in order to preserve the interface from contaminations that would obstruct the optimal atomic stratification with the desired [0001] growth axis. The piezoelectric behavior was thus correlated to the degree of texturing of the AlN layer through the evaluation of the XRD texturing coefficients and to the morphology by means of AFM analyses. We show that a high level of roughness introduced by the PEN substrate, coupled with the effect of the substrate flexibility on the piezoelectric coefficient, reduces the impact of the AlN texturing on the d(33) values. (C) 2015 AIP Publishing LLC.

AlN texturing and piezoelectricity on flexible substrates for sensor applications

MIRABELLA, SALVATORE;CONDORELLI, Guglielmo Guido;
2015

Abstract

We show that AlN-based piezocapacitors with relatively high piezoelectric coefficient (d(33)) values (3-4 pC/N) can be fabricated on polyimide (PI) substrates at 160 degrees C or even at room temperature by sputtering processes. With respect to PI, a reduction of the piezoelectric performances was observed on polyethylene naphthalate (PEN). With the same approach, a d(33) value as high as 8 pC/N was achieved on rigid substrates (SiO2/Si). In all cases, a thin Al buffer layer was deposited, immediately before AlN, without breaking the vacuum in the deposition chamber, in order to preserve the interface from contaminations that would obstruct the optimal atomic stratification with the desired [0001] growth axis. The piezoelectric behavior was thus correlated to the degree of texturing of the AlN layer through the evaluation of the XRD texturing coefficients and to the morphology by means of AFM analyses. We show that a high level of roughness introduced by the PEN substrate, coupled with the effect of the substrate flexibility on the piezoelectric coefficient, reduces the impact of the AlN texturing on the d(33) values. (C) 2015 AIP Publishing LLC.
File in questo prodotto:
File Dimensione Formato  
AlN-texturing-and-piezoelectricity-on-flexible-substrates-for-sensor-applications2015Applied-Physics-Letters.pdf

non disponibili

1.41 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11769/19181
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 26
  • ???jsp.display-item.citation.isi??? 25
social impact