Title :
A novel approach for leakage current reduction of LPCVD Ta/sub 2/O/sub 5/ and TiO/sub 2/ films by rapid thermal N/sub 2/O annealing
Author :
Sun, S.C. ; Chen, T.F.
Author_Institution :
Dept. of Electron. Eng., Nat. Chiao Tung Univ., Hsinchu, Taiwan
Abstract :
Rapid thermal N/sub 2/O annealing (RTN/sub 2/O) has been applied to reduce the leakage current in the Ta/sub 2/O/sub 5/ and TiO/sub 2/ thin films (100-200 /spl Aring/) prepared by low-pressure chemical vapor deposition (LPCVD) for the first time. Among three different post-deposition annealing conditions compared: (a) 800/spl deg/C rapid thermal O/sub 2/ annealing (RTO) for 60 sec, (b) 800/spl deg/C furnace O/sub 2/ annealing for 30 min and (c) 800/spl deg/C RTN/sub 2/O for 60 sec, RTN/sub 2/O has resulted the lowest leakage current and best time-dependent dielectric breakdown (TDDB) characteristics in Ta/sub 2/O/sub 5/ films. However, furnace O/sub 2/ annealing produces the lowest leakage in LPCVD-TiO/sub 2/ films. An increase in RTN/sub 2/O temperature above 800/spl deg/C decreases both high field leakage current and the effective dielectric constant. It also induces a low-field leakage current due to the reaction between high dielectric constant materials and the bottom electrode.<>
Keywords :
CVD coatings; DRAM chips; dielectric thin films; electric breakdown; leakage currents; permittivity; rapid thermal annealing; tantalum compounds; titanium compounds; 100 to 200 angstrom; 30 min; 60 s; 800 degC; DRAMs; LPCVD; N/sub 2/O; O/sub 2/; Ta/sub 2/O/sub 5/; Ta/sub 2/O/sub 5/ thin films; TiO/sub 2/; TiO/sub 2/ thin films; effective dielectric constant; furnace O/sub 2/ annealing; leakage current reduction; low-pressure chemical vapor deposition; post-deposition annealing conditions; rapid thermal N/sub 2/O annealing; storage dielectrics; time-dependent dielectric breakdown; Chemical vapor deposition; Dielectric breakdown; Dielectric constant; Dielectric materials; Furnaces; High-K gate dielectrics; Leakage current; Rapid thermal annealing; Sputtering; Temperature;
Conference_Titel :
Electron Devices Meeting, 1994. IEDM '94. Technical Digest., International
Conference_Location :
San Francisco, CA, USA
Print_ISBN :
0-7803-2111-1
DOI :
10.1109/IEDM.1994.383400
