Novel InGaSb/AlP Quantum Dots for Non-Volatile Memories

Abstract

Non-volatile memories based on the flash architecture with self-assembled III-V quantum dots (SAQDs) used as a floating gate are one of the prospective directions for universal memories. The central goal of this field is the search for a novel SAQD with hole localization energy (<i>E</i>_loc) sufficient for a long charge storage (10 years). In the present work, the hole states' energy spectrum in novel InGaSb/AlP SAQDs was analyzed theoretically with a focus on its possible application in non-volatile memories. Material intermixing and formation of strained SAQDs from a Ga<i>_x</i>Al_1-<i>x</i>Sb<i>_y</i>P_1-<i>y</i>, In<i>_x</i>Al_1-<i>x</i>Sb<i>_y</i>P_1-<i>y</i> or an In<i>_x</i>Ga_1-<i>x</i>Sb<i>_y</i>P_1-<i>y</i> alloy were taken into account. Critical sizes of SAQDs, with respect to the introduction of misfit dislocation as a function of alloy composition, were estimated using the force-balancing model. A variation in SAQDs' composition together with dot sizes allowed us to find that the optimal configuration for the non-volatile memory application is GaSbP/AlP SAQDs with the 0.55-0.65 Sb fraction and a height of 4-4.5 nm, providing the <i>E</i>_loc value of 1.35-1.50 eV. Additionally, the hole energy spectra in unstrained InSb/AlP and GaSb/AlP SAQDs were calculated. <i>E</i>_loc values up to 1.65-1.70 eV were predicted, and that makes unstrained InGaSb/AlP SAQDs a prospective object for the non-volatile memory application.