ALD processes for low leakage current and low equivalent oxide thickness BiTaO films
View Patent ↗A high dielectric constant (k≥40), low leakage current (≤10 −6 A/cm 2 at 0.6 nm or lower equivalent oxide thickness) non-crystalline metal oxide is described, including an oxide of two or more compatible metals selected from the group consisting of bismuth, tantalum, niobium, barium, strontium, calcium, magnesium, titanium, zirconium, hafnium, tin, and lanthanide series metals. Metal oxides of such type may be formed with relative proportions of constituent metals being varied along a thickness of such oxides, to enhance their stability. The metal oxide may be readily made by a disclosed atomic layer deposition process, to provide a metal oxide dielectric material that is usefully employed in DRAM and other microelectronic devices.
1. A high dielectric constant, low leakage current non-crystalline metal oxide, comprising an oxide of two or more compatible metals selected from the group consisting of bismuth, tantalum, niobium, barium, strontium, calcium, magnesium, titanium, zirconium, hafnium, tin, and lanthanide series metals, the metal oxide having a dielectric constant in a range of from 40 to 75, and a leakage current in a range of from 10 −6 A/cm 2 to 10 −9 A/cm 2 at 0.6 nm or lower equivalent oxide thickness, in a microelectronic device structure including a bottom electrode on which the high dielectric constant, low leakage current non-crystalline metal oxide is deposited, and a top electrode formed on the high dielectric constant, low leakage current non-crystalline metal oxide, optionally with a metal oxide capping layer between the high dielectric constant, low leakage current non-crystalline metal oxide and the top electrode.
2. The high dielectric constant, low leakage current non-crystalline metal oxide of claim 1 , comprising metal oxide selected from the group consisting of BiTaO, LnTaO, LnTiO, (Ba,Sr) tetratitanates, and ZrTiSnO, wherein Ln comprises a lanthanide series metal.
3. The high dielectric constant, low leakage current non-crystalline metal oxide of claim 1 , comprising BiTaO.
4. The high dielectric constant, low leakage current non-crystalline metal oxide of claim 1 , in which the metal oxide comprises different relative proportions of the metals therein.
5. The high dielectric constant, low leakage current non-crystalline metal oxide of claim 1 , wherein the high dielectric constant, low leakage current non-crystalline metal oxide is annealed at a temperature below crystallization temperature.
6. The high dielectric constant, low leakage current non-crystalline metal oxide of claim 3 , wherein metal proportions are 3Bi:2Ta.
7. The high dielectric constant, low leakage current non-crystalline metal oxide of claim 3 , wherein metal proportions are 5Bi:4Ta.
8. The high dielectric constant, low leakage current non-crystalline metal oxide of claim 3 , wherein metal proportions are 1Bi:1Ta.
9. The high dielectric constant, low leakage current non-crystalline metal oxide of claim 3 , wherein metal proportions are 4Bi:5Ta.
10. The high dielectric constant, low leakage current non-crystalline metal oxide of claim 3 , wherein metal proportions are 2Bi:3Ta.
11. The high dielectric constant, low leakage current non-crystalline metal oxide of claim 3 , wherein metal proportions are 1Bi:2Ta.
12. A high dielectric constant, low leakage current non-crystalline metal oxide, comprising LnTaO, wherein Ln comprises a lanthanide series metal.
13. A high dielectric constant, low leakage current non-crystalline metal oxide, comprising LnTiO, wherein Ln comprises a lanthanide series metal.
14. A high dielectric constant, low leakage current non-crystalline metal oxide, comprising ZrTiSnO.