Giwan Yoon

Film Bulk Acoustic Resonator Fabrication for Radio Frequency Filter Applications

In this paper, a two-step radio frequency (RF) sputtering deposition technique for piezoelectric ZnO film formation and its successful application for film bulk acoustic resonator (FBAR) devices are presented. Several critical parameters of the RF sputtering process such as deposition pressure, RF power and O2 concentration were studied to clarify their effects on the material characteristics of the ZnO films. The ZnO films deposited by the proposed two-step deposition are shown to have the growth characteristic of strongly preferred orientation toward the c-axis. The FBAR devices with the ZnO films showed a large return loss of ~50 dB at the center frequency of 1.49 GHz. It was also found that the impedance matching of the FBAR could be easily achieved simply by controlling the resonance area of the resonator.

Two-step deposition process of piezoelectric ZnO film and its application for film bulk acoustic resonators

In this article, a two-step deposition technique of piezoelectric zinc oxide (ZnO) film formation using radio-frequency (rf) sputtering and its successful applications for film bulk acoustic resonators (FBAR) are presented. Several critical sputtering process parameters such as deposition pressure, rf power, and O2 concentration were investigated to understand their impacts on the resulting crystal structures and surface morphologies of the ZnO films. The ZnO films formed by the two-step deposition have shown the growth characteristic of the strongly preferred orientation toward c axis. The FBAR with the ZnO films showed a large return loss of ∼50 dB at the center frequency of 1.49 GHz. It was also found that the impedance matching of the FBAR could be easily achieved by simply controlling the resonance area of the resonator.

Characterization of High Quality Nitrided Gate Dielectric Films Manufactured in Reduced Pressure Furnace for Ultralarge Scale Integration Complementary Metal Oxide Semiconductor Applications

High quality, ultrathin nitrided gate dielectric films were investigated to study their effects on device performance and reliability for ultralarge scale integration complementary metal oxide semiconductor applications. Thermal nitridation was performed on 200 mm wafers in a vertical reduced pressure furnace using N 2 O and/or NH 3 . It was demonstrated that nitrided gate dielectric films (ROXNOX, N 2 O oxide) have improved hot carrier lifetime and barrier properties to boron diffusion. In addition, N 2 O oxides, as well as ROXNOX, were found to be a promising alternative gate dielectric to the conventional oxide.

A new fabrication technique for 2.75 GHz ZnO-based FBAR devices

We for the first time present a new fabrication technique of ZnO-based FBAR devices using a multi-layered Bragg reflector. To improve the resonance performance, 0.03?m-thick chromium (Cr)-adhesion layers were inserted into the Bragg reflector and also thermal treatments were made to the devices. At operating frequency of about 2.75 GHz, very high return loss values and quality factor (Q) were observed under an optimum thermal annealing condition.

Metal-Oxide-Semiconductor Characteristics of NH3-Nitrided N2O-Annealed Oxides Fabricated at Reduced Pressure

In this paper, a new technique, namely, the fabrication of NH3-nitrided N2O-annealed oxides (NNO) under reduced pressure, is presented to attain the desired nitrogen concentrations and profiles that eventually improve the hot-carrier lifetime and high immunity to boron penetration. The proposed NNO dielectrics fabricated at reduced pressure (<550 Torr) showed excellent hot-carrier lifetimes and barrier properties to boron penetration without any adverse effects on the electrical properties and reliability.