Flexibly-Shaped-Pulse Flash Lamp Annealing with Assisted Temperature Control (FSP-FLAplus) to Realize a Wide Range of Annealing Conditions

摘要

Millisecond annealing (MSA), such as flash lamp annealing (FLA) and laser spike annealing, is used for dopant activation of ultra-shallow junctions (USJ) in scaled complimentary metal-oxide-semiconductor (CMOS) devices. This is because lower sheet resistance (Rs) and less dopant diffusion are achieved with MSA and these are crucial requirements for minimizing the junction depth (Xj) in state-of-the-art CMOS [1-5]. In FLA the sample is irradiated for a few milliseconds with a Xe-lamp after pre-heating to 500 °C or more. The assisted heating is done either using a resistive heater or by irradiation with a halogen lamp. With lamp heating, the assisted temperature (TA) range is from 500 to 1000 °C compared with from 300 to 600 °C using a resistive heater. In addition, with lamp assisted heating the temperature profile can be controlled to the second order, similar to spike rapid thermal annealing (sRTA). Thus, we can use higher TA with less dopant diffusion, and higher pre-heat temperatures enable higher peak temperatures during Xe-lamp irradiation. We also used a Flexibly-Shaped-Pulse (FSP) system to control the annealing time and temperature [6-10]. By combining FSP technology with lamp assisted heating, we expect to be able to have control over a wide-range of annealing times and temperatures. In addition, this combination may produce a synergistic effect on device performance. In this report, we examine, first, the effects of high assisted temperatures. Then, we demonstrate the excellent potential of combining FSP technology and lamp assisted heating on device performance.