Title :
MOSFET transistors fabricated with high permitivity TiO2 dielectrics
Author :
Campbell, Stephen A. ; Gilmer, David C. ; Wang, Xiao-chuan ; Hsieh, Ming-ta ; Kim, Hyeon-Seag ; Gladfelter, Wayne L. ; Yan, Jinhua
Author_Institution :
Dept. of Electr. Eng., Minnesota Univ., Minneapolis, MN, USA
fDate :
1/1/1997 12:00:00 AM
Abstract :
Layers of polycrystalline anatase TiO2 have been deposited through the thermal decomposition of titanium tetrakisisopropoxide (TTIP). 500 Å films deposited and annealed in oxygen at 750°C had average roughnesses (Ra) of about 30 Å. Capacitors made from 190 Å layers of TiO2 displayed a voltage dependent accumulation capacitance. This was postulated to be caused by finite width effects in the accumulation layer which we have dubbed the quantum capacitance effect. N-channel transistors made with these films showed near ideal behavior, but mobilities were significantly lower than those of thermal oxide MOSFETs. This mobility reduction was believed to be caused by interface states, which fell below 1011 cm-2 eV-1 at midgap, but rose sharply on either side, unlike the “U” shaped behavior in thermal oxide MOSFET´s
Keywords :
MOS capacitors; MOSFET; accumulation layers; annealing; carrier mobility; dielectric thin films; interface states; pyrolysis; semiconductor technology; titanium compounds; 190 angstrom; 500 angstrom; 750 C; MOSFET; N-channel transistors; O2 annealing; Si-TiO2; accumulation layer; average roughnesses; capacitors; finite width effects; high permitivity TiO2 dielectrics; interface states; mobility reduction; near ideal behavior; polycrystalline anatase; quantum capacitance effect; thermal decomposition; titanium tetrakisisopropoxide; voltage dependent accumulation capacitance; Annealing; Dielectric materials; Dielectric substrates; Dielectric thin films; Leakage current; MOSFET circuits; Photonic band gap; Quantum capacitance; Thermionic emission; Tunneling;
Journal_Title :
Electron Devices, IEEE Transactions on
