Capacitorless single transistor dynamic random-access memory (1T-DRAM) cells on silicon-germanium-on-insulator (SGOI) substrates with various Ge mole fractions in the relaxed-SiGe layers were investigated. SGOI substrates with strained-Si channels showed higher on-currents and carrier mobility than a silicon-on-insulator (SOI) substrate with unstrained-Si channels. SGOI 1T-DRAM devices had larger memory windows than a similar device with SOI; memory window increased with increasing Ge mole fraction in the relaxed-SiGe layer. The SGOI 1T-DRAMs showed degraded retention times. High-temperature annealing reduced the effects of crystalline defects and thus improved the electrical properties of the SGOI substrates, leading to higher carrier mobility, larger memory window, and longer data retention. (C) 2012 Elsevier B. V. All rights reserved.