Yttrium oxide/silicon dioxide: a new dielectric structure forVLSI/ULSI circuits |
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Authors: | Manchanda L Gurvitch M |
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Affiliation: | AT&T Bell Labs., Murray Hill, NJ; |
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Abstract: | Electrical characteristics of Al/yttrium oxide (~260 Å)/silicon dioxide (~40 Å)/Si and Al/yttrium oxide (~260 Å)/Si structures are described. The Al/Y2O3/SiO2/Si (MYOS) and Al/Y2 O3/Si (MYS) capacitors show very well-behaved I-V characteristics with leakage current density <10-10 A/cm2 at 5 V. High-frequency C- V and quasistatic C-V characteristics show very little hysteresis for bias ramp rate ranging from 10 to 100 mV/s. The average interface charge density (Qf+Q it) is ~6×1011/cm2 and interface state density Dit is ~1011 cm-2-eV-1 near the middle of the bandgap of silicon. The accumulation capacitance of this dielectric does not show an appreciable frequency dependence for frequencies varying from 10 kHz to 10 MHz. These electrical characteristics and dielectric constant of ~17-20 for yttrium oxide on SiO2/Si make it a variable dielectric for DRAM storage capacitors and for decoupling capacitors for on-chip and off-chip applications |
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