Improved reliability characteristics of Ge MOS devices by capping Hf or Zr on interfacial layer

Ultralow equivalent oxide thickness and excellent reliability characteristics in Ge MOS devices with ZrO2 gate dielectrics are achieved by capping Hf or Zr on interfacial layer. Device with a Hf-cap layer demonstrates the lowest interface trap density and stress-induced leakage current. On the other hand, device with a Zr-cap layer exhibits the lowest hysteresis effects and stress-induced voltage shifts. The HfGeOx IL of high quality and ZrGeOx IL with few oxide traps are promising to improve reliability characteristics in Ge MOS devices.