Low-dose n-type nitrogen implants in 4H-SiC

Lightly-doped n-type layers have been fabricated in 4H-SiC by low-dose implantation of nitrogen ions and characterized using the Hall effect. Near-bulk electron mobility is achieved in the implanted layers. Activation rates for the implanted nitrogen ions, energies and densities of the two-level nitrogen donor, and compensation are found from fitting the measured Hall free-electron density to a charge neutrality model as a function of temperature. Measured nitrogen activation rates are 55% and 71% for 1300 and 1600 °C anneal temperatures, respectively. Compensation due to unannealed implant damage is 32% and 17% of the implant dose for 1300 and 1600 °C anneal temperatures, respectively.