Office of Technology Transfer – University of Michigan

Non-Thermal Semiconductor Doping Via Femtosecond-Scale Laser Irradiation

Technology #7084

Semiconductor devices often utilize electronic doping, which is the addition of chemical impurities of the material, e.g., to alter electrical conductivity. The doping process for most semiconductor materials requires elevated temperatures to incorporate and activate dopants. However, subjecting semiconductor materials to elevated temperatures can also degrade properties of the material, and can limit the process design and applications of the semiconductor materials. A method of introducing dopants that avoids heating the material could have an impact in the flexible electronics and high-power electronics markets. The flexible electronics market is projected to reach $13.23B by 2020 [1], and the energy market of high-power electronics was $1.9B in 2013 [2]. The method described below achieves doping at low temperatures using femtosecond laser pulses.

Non-Thermal Semiconductor Doping

Femtosecond laser pulses are capable producing non-thermal (or cold) melting, and the introduction of impurity elements in combination with the laser pulses allows the introduction of dopants to the target area of the laser. In contrast to excimer laser irradiation, the method described here avoids thermal interaction in the material while achieving localized doping. The findings are supported through experimental validation where electrical conductivity changes of several orders of magnitude were achieved. The technology impacts the consumer electronics, energy, defense, automotive, and industrial sectors, and its specific applications include high-power electronics, transparent or flexible electronics, and sensors operating in harsh environments, e.g., near combustion engines.

Applications

  • Devices for high-power electronics, e.g. power switches
  • Sensors operating in harsh environments, e.g., near combustion engines
  • Transparent or flexible electronics

Advantages

  • Non-thermal doping
  • Localized doping
  • Conduction changes of several orders of magnitude
  • Process carried out at low temperatures

[1] Flexible Electronics Market worth $13.23 Billion by 2020. SE 2571. Markets and Markets. 2014 [2] Power Electronics: Technologies and Global Markets. EGY057B. BCC Research. 2015.