Diode-Like Current Leakage and Ferroelectric Switching in Silicon SIS Structures with Hafnia-Alumina Nanolaminates.

Silicon semiconductor-insulator-semiconductor (SIS) structures with high-k dielectrics are a promising new material for photonic and CMOS integrations. The "diode-like" currents through the symmetric atomic layer deposited (ALD) HfO/AlO/HfO… nanolayers with a highest rectification coefficient 10 are observed and explained by the asymmetry of the upper and lower heterointerfaces formed by bonding and ALD processes. As a result, different spatial charge regions (SCRs) are formed on both insulator sides. The lowest leakages are observed through the stacks, with total AlO thickness values of 8-10 nm, which also provide a diffusive barrier for hydrogen. The dominant mechanism of electron transport through the built-in insulator at the weak field E < 1 MV/cm is thermionic emission. The Poole-Frenkel (PF) mechanism of emission from traps dominates at larger E values. The charge carriers mobility 100-120 cm/(V s) and interface states (IFS) density 1.2 × 10 cm are obtained for the n-p SIS structures with insulator HfO:AlO (10:1) after rapid thermal annealing (RTA) at 800 °C. The drain current hysteresis of pseudo-metal-oxide-semiconductor field effect transistor (MOSFET) with the memory window 1.2-1.3 V at the gate voltage |V| < ±2.5 V is maintained in the RTA treatment at T = 800-900 °C for these transistors.