What is ion implantation?
Ion implantation is doping that can achieve controlled quantity and quality, Ion implantation is the most important doping method.
Doping changes the electrical properties of the wafer. Due to the poor electrical conductivity of intrinsic silicon (ie, silicon single crystal without impurities), it can only function as a semiconductor when an appropriate amount of impurities is added to the silicon to change its structure and electrical properties. This process is called doping. Silicon doping is the basis for the preparation of P-N junctions in semiconductor devices. It refers to doping the required impurity atoms into a specific semiconductor region to locally dope the substrate and change the electrical properties of the semiconductor. It has been widely used in chips. The whole process of manufacturing. In chip manufacturing, both thermal diffusion and ion implantation can introduce impurity elements into silicon wafers. The specific differences are as follows:
Thermal Diffusion: Using high temperature to drive impurities through the lattice structure of silicon, the effect of doping is affected by time and temperature.
Ion implantation: The impurity is introduced into the silicon wafer by high-voltage ion bombardment, and the impurity can be implanted after the atomic-level high-energy collision with the silicon wafer.In the ion implantation process, the implanted ions include B, P, As, Sb, C, Si, Ge, O, N, H ions, and so on.
Precise controllability makes ion implantation the most important doping method. With the continuous reduction of chip feature size and the increase in integration, various devices are also constantly shrinking. Since the performance of transistors is increasingly affected by the doping profile, ion implantation is the only means that can accurately control doping and can repeat control of doping concentration and depth has resulted in the transition from thermal diffusion to ion implantation for almost all doping processes in modern wafer fabrication.
