The silicon dioxide (SiO2) was deposited using various gas as oxygen and nitrous oxide (N2O) in nowadays. In order to improve electrical characteristics and the interface state density (D_{it}) in low temperature, It was deposited with carbon dioxide (CO2) and silane (SiH4) gas by inductively coupled plasma chemical vapor deposition (ICP-CVD). Each D_{it} of SiO2 using CO2 and N2O gas was 1.30×1010 cm-2·eV-1 and 3.31×1010 cm-2·eV-1. It showed SiO2 using CO2 gas was about 2.55 times better than N2O gas. After 10 years when the thin film was applied to metal/insulator/semiconductor(MIS)-nonvolatile memory(NVM), MIS NVM using SiO2(CO2) on tunneling layer had window memory of 2.16 V with 60% retention at bias voltage from +16 V to -19 V. However, MIS NVM applied SiO2(N2O) to tunneling layer had 2.48 V with 61% retention at bias voltage from +20 V to -24 V. The results show SiO2 using CO2 decrease the D_{it} and it improves the operating voltage.

Dual-gate PCRAM which unify capacitor-less DRAM and NVM using a PCM instead of a typical SONOS flash memory is proposed as 1 transistor. VO2 changes its phase between insulator and metal states by temperature and field. The front-gate and back-gate control NVM and DRAM, respectively. The feasibility of URAM is investigated through simulation using c-interpreter and finite element analysis. Threshold voltage of NVM is 0.5 V that is based on measured results from previous fabricated 1TPCM with VO2. Current sensing margin of DRAM is 3 ㎂. PCM does not interfere with DRAM in the memory characteristics unlike SONOS NVM. This novel unified dual-gate PCRAM reported in this work has 1 transistor, a low RESET/SET voltage, a fast write/erase time and a small cell so that it could be suitable for future production of URAM.