The Process and Mechanism of Preparing Nanoporous Silicon: Helium Ion Implantation

Ion implantation is an effective way to control performance in semiconductor technology. In this paper, the fabrication of 1 similar to 5 nm porous silicon by helium ion implantation was systemically studied, and the growth mechanism and regulation mechanism of helium bubbles in monocrystalline silicon at low temperatures were revealed. In this work, 100 keV He ions (1 similar to 7.5 x 10(16) ions/cm(2)) were implanted into monocrystalline silicon at 115 degrees C similar to 220 degrees C. There were three distinct stages in the growth of helium bubbles, showing different mechanisms of helium bubble formation. The minimum average diameter of a helium bubble is approximately 2.3 nm, and the maximum number density of the helium bubble is 4.2 x 10(23) m(-3) at 175 degrees C. The porous structure may not be obtained at injection temperatures below 115 degrees C or injection doses below 2.5 x 10(16) ions/cm(2). In the process, both the ion implantation temperature and ion implantation dose affect the growth of helium bubbles in monocrystalline silicon. Our findings suggest an effective approach to the fabrication of 1 similar to 5 nm nanoporous silicon, challenging the classic view of the relationship between process temperature or dose and pore size of porous silicon, and some new theories are summarized.

Automated summary

This study systematically investigated the fabrication of 1 to 5 nm porous silicon using helium ion implantation and revealed the growth and regulation mechanism of helium bubbles in monocrystalline silicon at low temperatures. The growth of helium bubbles can be divided into three distinct stages, each with different formation mechanisms. The minimum average diameter of a helium bubble is approximately 2.3 nm, with a maximum number density of 4.2 x 10^23 m^-3. The porous structure cannot be obtained at injection temperatures below 115℃ or injection doses below 2.5 x 10^16 ions/cm^2. Both the ion implantation temperature and dose have an impact on the growth of helium bubbles in monocrystalline silicon. This research provides an effective approach for fabricating 1 to 5 nm nanoporous silicon, challenging traditional views and proposing new theories.