Utilizes Low Energy Germanium Implantation to Create the Desired Number of Defects in Silicon Substrate
This addition of germanium ions to a silicon substrate allows for control over the number of interstitial point defects, a discovery that could be used to create unique dopant profiles in semiconductor device structures. The thermal oxidation of silicon injects interstitial point defects that affect certain material behaviors, such as diffusion and defect formation, which are relevant to the fabrication of microelectronics. An additional layer of germanium at the oxidizing interface prevents interstitial point defects during oxidation.
However, researchers at the University of Florida have determined that the addition of germanium does not entirely suppress interstitial injection. In fact, controlling the dose of germanium into silicon allows them to control the rate and location of interstitial injection; within the field of semiconductor manufacturing, this could allow a single anneal step to achieve differential and controlled diffusion in different regions of a microelectronic circuit.
Control over the number of interstitial injections during the thermal oxidation of silicon for microelectronics
- Implants a variant dose of germanium ions into a silicon substrate, altering the rate of interstitial injection during thermal oxidation
- Modulates dopant diffusion behavior in the region below the implant, allowing for the control of junction depths
- Achieves differential and controlled diffusion in different regions of a microelectronic circuit
- Modulates extended defect growth rates in different areas of a device in applications where such defects are desirable
This modulation procedure developed by University of Florida researchers controls the rate of interstitial injections during thermal oxidation by altering the germanium dose. Implanting the desired number of germanium ions into the silicon surfaces forms a doped silicon substrate. Then the substrate heats in a dry oxidizing ambient environment to allow the implanted germanium ions to form a superficial layer on the surface of the silicon substrate. The germanium implantation dose and energy can be uniform or non-uniform across the surface. Processes such as selective patterning, masking, or implantation can achieve non-uniform germanium implantation. This allows for control of the junction depths by modulating dopant diffusion behavior in the region below the implant, which is important for semiconductor manufacturing.