講演情報
[14a-K201-6]Ripple structure formation on GaAs using Ar plasma irradiation
〇(PC)Quan Shi1, Shin Kajita1, Noriyasu Ohno2 (1.Univ. Tokyo, 2.Nagoya Univ.)
キーワード：
Plasma processing、Ripple structure
Gallium arsenide (GaAs) with nanoscale pattern is popular for semiconductor applications due to its unique optical and electrical properties [1]. Ion etching technique, such as ion beam etching, is widely used to form various kinds of surface pattern. Particularly, ripple structure can be easily formed when ions bombarded to the surface in an oblique angle [2]. However, the incident ion energy of ion beam is usually large (> 500 eV) which could lead to defects in semiconductor substrate materials. Plasma irradiation could control the ion energy in a small level conveniently by changing the bias on the sample. Nevertheless, due to the fact that the electric field in the plasma sheath is usually perpendicular to the material surface, there has been limited research on the inclined etching of materials by plasma. This study utilized an inclined magnetic field with respect to the surface normal and the influence of surrounding metals on the sheath of the substrate material to achieve inclined ion incidence, forming ripple structures on the surface of GaAs material.
Figs. 1(a-c) shows the GaAs ripple structure formed after the argon (Ar) plasma irradiation with RF bias. As the irradiation time increases, ripple becomes clear after 80 min. Fig 1(d) is the power spectra of horizontal lines on (a-c), which indicate the wavelength of the ripple. After 40 minutes of irradiation, the wavelength of the ripples is approximately 50 nm. After 80 minutes, it decreases to about 40 nm and remains unchanged even with longer irradiation times.
Figs. 1(a-c) shows the GaAs ripple structure formed after the argon (Ar) plasma irradiation with RF bias. As the irradiation time increases, ripple becomes clear after 80 min. Fig 1(d) is the power spectra of horizontal lines on (a-c), which indicate the wavelength of the ripple. After 40 minutes of irradiation, the wavelength of the ripples is approximately 50 nm. After 80 minutes, it decreases to about 40 nm and remains unchanged even with longer irradiation times.