Stress Engineering With Silicon Nitride Stressors for Ge-on-Si Lasers

Abstract

Side and top silicon nitride stressors were proposed and shown to be effective in reducing the threshold current Ith and in improving the wall-plug efficiency ηwp of Ge-on-Si lasers. Side stressors only turned out to be a more efficient way to increase ηwp than using the top and side stressors together. With the side stressors and geometry optimizations, a ηwp of 34.8% and an Ith of 36 mA (Jth of 27 kA/cm2) can be achieved with a defect limited carrier lifetime (τp,n) of 1 ns. With τp,n = 10 ns, an I th of 4 mA (Jth of 3 kA/cm2) and a ηwp of 43.8% can be achieved. These are tremendous improvements from the case with no stressors. These results give strong support to the Ge-on-Si laser technology and provide an effective way to improve the Ge laser performance.

Keywords

• Germanium
• semiconductor lasers
• silicon photonics