Thin Film Fabrication Techniques

Abstract

Thin film fabrication process involves many considerations in order to obtain desired devices in the electronics domain. The bottom-up techniques which are used to synthesize thin films have numerous advantages and applications as far as VLSI (very large-scale integration) technology and nano-electronics are considered. If we take into consideration of physical processes, then under evaporation, thermal, molecular beam epitaxy, e-beam, laser, ion-plating are considered. Similarly, under sputtering, DC, RF, Magnetron are taken into contemplation. Further with respect to chemical processes, which include thermal, MOCVD (metal-organic chemical vapor deposition), PECVD (plasma enhanced chemical vapor deposition); similarly, under plating, electroplating, electroless along with sol-gel method and ALE (Atomic layer epitaxy) are considered to be requisite thin film synthesis process. Modern thin film growth techniques like molecular beam epitaxy (MBE) have demonstrated the ability to produce samples with carrier mobilities that are higher than those of bulk crystals while having complete control over the growth rate. This technology is essential for establishing the correct stoichiometry and layer-by-layer growth. We may create a thin film hall bar device for the same sample holder using two physical masks: one for reactive ion etching (RIE), also known as an etching mask, and the other for depositing metal electrodes, also known as a metal mask. While the etching mask is used to specify the size of the thin film Hall bar, the metal mask is utilized to deposit the metal electrodes. After the sample is made from the MBE, the thin film Hall bar can be made using RIE and an etching mask placed over the sample on the sample holder. The etching can be done using the required gas for a predetermined period of time to produce the required Hall bar structure. The metal mask can also be utilized to construct metal ohmic connections by applying heat evaporation to a thin film Hall bar sample.