45.2: Effects of RF Sputtering Parameters and Film Composition on C‐Axis Aligned Crystalline (CAAC) IGZO Films

Abstract

The influence of deposition parameters on the properties of RF sputter deposited c-axis aligned crystalline (CAAC) IGZO was evaluated using both single parameter and design of experiment (DOE) analysis. Deposition temperature and oxygen partial pressure were found to be primary parameters determining CAAC alignment and crystallinity. CAAC is first formed at a deposition temperature of 185 o C, reaching optimal surface normal alignment at ~315 o C. Crystallinity and alignment increase rapidly with oxygen fraction up to 10%, then becoming nearly independent up to 50%. The Zn fraction and (Ga+Zn)/In ratio were identified as key parameters correlated to c-axis texture in the films. Zinc loss during deposition at high temperatures and low oxygen partial pressures correlated with poor CAAC alignment, while (Ga+Zn)/In ratio approaching an ideal 2.0 ratio exhibited improved CAAC crystallinity. Author KeywordsIGZO, c-axis alignment, thin film, sputtering, design of experiment (DOE).

45-3: A Novel Seamless Kawara-type Multidisplay with Flexible OLED Panels Using an Optically Isotropic Film

“…We have developed our own equipment to automate this separation process, making this technology suitable for mass production [7]. The FETs use c-axis-aligned crystalline indium gallium zinc oxide [8][9][10][11][12][13], and color display is achieved with a "white tandem OLED, top emission, and color filter" (WTC) structure [14][15][16]. Transparent electrodes with different thicknesses for different colors are provided on reflective electrodes, i.e., a microcavity structure is employed.…”

7-2: Transmissive OLED and Reflective LC Hybrid (TR-Hybrid) Display

“…We discovered CAAC-IGZO and nanocrystalline IGZO (nc-IGZO), which have crystal morphologies different from those of single crystal and amorphous IGZOs [9][10][11][12]. Cornell University has also investigated CAAC-OS [13][14][15][16][17][18]. In CAAC-IGZO films, atomic arrangement parallel to a substrate surface is observed by cross-sectional transmission electron microscopy (TEM).…”

37-2: 1058-ppi 4K LC Display Using a Top-Gate Self-Aligned CAAC-OS FET

“…To develop low-power, high-resolution displays, our research focused on oxide semiconductors. Oxide semiconductors have a wide range of crystallinities beyond the single-crystal state, and these alternatives have been studied in previous research [1][2][3][4][5][6][7][8][9]. In particular, we used a c-axis aligned crystalline oxide semiconductor (CAAC-OS) to fabricate highly reliable field-effect transistors (FETs) [10][11][12][13][14].…”