Chip Manufacturing: Dielectric Materials Regulate the Electric Field

In the chip, various insulating dielectric materials silently regulate the electric field distribution through their unique dielectric constants, which ultimately determine the efficiency of the transistor and the performance of the chip. From classic silica to revolutionary high-K materials, each medium plays an irreplaceable role in a specific location on the chip.

As the most traditional insulating material, silica has long played a central role in gate media with its stable chemical properties and ideal silicon interface properties. With a relative dielectric constant of approximately 3.9, it excels in the early stages of micro- to nano-processing. However, as the process shrinks, the silica layer needs to be continuously thinned to maintain sufficient gate control capabilities. When the thickness is close to 1 nanometer, the quantum tunneling effect causes a sharp increase in gate leakage current, like a dam that is too thin to block the water flow, causing the static power consumption of the transistor to rise sharply.

Silicon nitride, with its high dielectric constant and excellent blocking properties, plays multiple roles in chips. Its dielectric constant is about 7, which is almost twice as high as silica, which allows it to provide greater capacitance at the same thickness. In memory chip capacitors, silicon nitride effectively improves the charge storage capacity per unit area as a dielectric layer. At the same time, its high-density characteristics make it an ideal diffusion barrier layer, which can effectively prevent the migration of impurity ions in the chip.

Silica nitrogen represents the crystallization of the wisdom of classical material systems. By introducing nitrogen into silica, the dielectric constant of the material is increased to about 5, while the boron penetration resistance and thermal stability are significantly enhanced. This improvement makes silicon oxide an ideal gate dielectric material in the 45nm to 28nm process nodes, effectively suppressing leakage current while maintaining sufficient gate control capability.

In the back-end interconnect layer of the chip, silicon carbide doped with the important mission of reducing parasitic capacitance. By introducing carbon into silica, the dielectric constant of the material can be reduced to less than 3.0. A lower dielectric constant means less electric field interaction between adjacent metal wires and reduced capacitive coupling, which directly translates into faster signal transmission and lower power consumption. In modern multi-level interconnect architectures, low-K media are like high-efficiency isolation bands between dense metal lines, ensuring signal integrity and transmission efficiency.