Breakdown and conduction mechanisms of ALD HfSiON dielectric with TaN gate using carrier separation analysis [MOSFETs]

For the first time, we evaluated the breakdown and conduction mechanisms of ALD HfSiON with TaN gate. In the unstressed HfSiON, hole current dominates the gate leakage current. Under the SILC condition, the electron trap generation from the band edge of the TaN gate and conduction band edge of the Si substrate is accelerated, resulting in an increase of electron current. After soft breakdown of the dielectric, the electron current is predominant in the gate leakage. We demonstrate that the electron tunneling current mainly contributes to the degradation and breakdown of HfSiON dielectric with TaN gate. The conduction mechanism of the electrons and holes is Fowler-Nordheim tunneling.