Materials Science Forum Vols. 778-780

Abstract: An effective acceptor level (E_A^eff) for representing the increased ionization ratio in extrinsically photon-recycled p-type GaN is proposed. E_A^eff at 300 K in the range of 0.1360.145 eV is found to reproduce current/voltage characteristics of transmission-line-model patterns formed with GaN p-n junction epitaxial layers and electrode spacing of 320 μm when the p-n diode current flowing through an 80×100-μm electrode is 90 mA. When E_A^eff is decreased from 0.160 eV to 0.145 eV, the on-resistance of 18×100-μm GaN bipolar transistors is predicted to be reduced by more than 50%.

Abstract: In this study, a gallium nitride (GaN) substrate grown by the Na flux method was processed by catalyst-referred etching (CARE). CARE process for GaN involves two-step: the first step uses the photoelectrochemical process (PEC-CARE) and the second step applies a platinum (Pt) catalyst (Pt-CARE). PEC-CARE can produce a highly ordered GaN (0001) surface. The surface roughness was 0.638 nm root-mean-square (rms). Pt-CARE can produce an atomically flat surface with a step-terrace structure on the entire surface. The surface roughness was 0.113 nm rms. The removal rates of PEC-CARE and Pt-CARE were found to be 45.5 and 5.5 nm/h, respectively.

Abstract: To solve the problem of the limitation to improve device performance in standard Si integration technologies and to develop radiation-harsh devices, the irradiation effects of Si_1-xC_x source/drain (S/D) n-type metal oxide semiconductor field effect transistors (n-MOSFETs) have been investigated. It is shown that the drain current and the maximum electron mobility of Si_1-xC_x n-MOSFETs decrease by electron irradiation. The reduction of the device performance can be explained by the radiation-induced lattice defects in the devices. However, the electron mobility enhancement effect by adding C remained after an electron irradiation up to 5×10¹⁷ e/cm².

Abstract: The structure of ZnO thin films grown in room temperature by reactive DC sputter technique on polyethylene terephthalate film were evaluated by SEM and TEM. The quality of ZnO thin films grown in room temperature were observed to vary widely. ZnO crystals grow without uniform orientation in early stage of growth, and then ZnO crystallinity improves as the ZnO thin films grow up. And ZnO crystallinity is influenced by roughened surface of PET film.