Atomic layer deposition of hafnium silicate film for high mobility pentacene thin film transistor applications

作者：Lee Seunghyup; Yun Dong Jin; Rhee Shi Woo; Yong Kijung^*

来源：Journal of Materials Chemistry, 2009, 19(37): 6857-6864.

DOI：10.1039/b908216f

The performance of pentacene thin film transistors (TFTs) was improved using a hafnium silicate (Hf(x)Si(1-x)O(2)) thin film as a high-k dielectric layer. For growth of the Hf(x)Si(1-x)O(2) thin films, an atomic layer chemical vapor deposition (ALCVD) process was optimized using silicon alkoxide and hafnium amido as precursors. The self-limiting surface reactions of each precursor were observed, indicating the ALCVD growth characteristics. The film thickness linearly increased depending on the number of process cycles, with a remarkably high growth rate of 2.3 angstrom per cycle. The chemical binding states, thermal stability and electrical characteristics of the films grown were investigated using XPS, XRD and capacitance-voltage and leakage current-voltage analysis. The pentacene TFTs fabricated with the ALCVD-grown Hf(0.67)Si(0.33)O(2) dielectric layer were characterized and the results were compared to the pentacene TFTs using Al(2)O(3) and SiO(2) film as dielectric layers. The pentacene/Hf(0.67)Si(0.33)O(2) TFT showed a three-fold and five-fold higher mobility than a pentacene/Al(2)O(3) TFT and a pentacene/SiO(2) TFT, respectively. With additional treatments to enhance the characteristics of the OTFT, pentacene/Hf(x)Si(1-x)O(2) TFTs have great potential as high mobility devices with low operational voltage.

• 出版日期2009