Effects of resist strip and clean on USJ performance

As junction depths decrease below 50 Aring, surface conditions before, during and after implantation have an increasing impact on the characteristics of the junction. Understanding the effects of photoresist strip and clean on the junction characteristics after annealing are critical to achieve expected and consistent device performance. Photoresist strip and clean is found to cause: junction etching, dopant bleaching and junction oxidation. Implant conditions can enhance these effects. Surprisingly, the strip and clean can also effect the dopant distribution, and possibly dopant activation. These effects are modified and many times enhanced by degree of amorphization, and vary significantly by type of activation anneal. Details of a parametric study show influence of resist strip parameters (power, pressure, temperature, chemistry) on surface oxidation, surface etching and surface passivation, as well unexpected interactions between the resist strip with the implant and anneal conditions.