Effects of annealing on electrical properties of Si/Si junctions by surface-activated bonding

Abstract

Effects of annealing on surface-activated bonding (SAB)-based Si/Si junctions were investigated by transmission electron microscopy (TEM) observations and current–voltage (I–V) measurements. We observed an amorphous-like layer at the bonding interface, which was recrystallized by annealing. We extracted the potential barrier heights at Si/Si interfaces annealed at different temperatures from the results of I–V measurements at various ambient temperatures. For p-Si/p-Si junctions, the barrier height increased as the annealing temperature increased from 200 to 400 °C and decreased from 400 to 1000 °C. For n-Si/n-Si junctions, the barrier height increased as the annealing temperature increased from 200 to 600 °C and decreased from 600 to 1000 °C. By using the charge neutral level (CNL) model, we estimated the energy of CNL, ECNL, and the density of interface states, Dit, at each annealing temperature. Dit decreased as the annealing temperature increased from 400 to 1000 °C. ECNL showed values larger than the reported ones.