Mixed metal nitride and boride barrier layers

Abstract

Mixed metal aluminum nitride and boride diffusion barriers and electrodes for integrated circuits, particularly for DRAM cell capacitors. Also provided are methods for CVD deposition of MxAlyNzBw alloy diffusion barriers, wherein M is Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, or W; x is greater than zero; y is greater than or equal to zero; the sum of z and w is greater than zero; and wherein when y is zero, z and w are both greater than zero.

Description

FIELD OF THE INVENTION [0001] The invention relates generally to integrated circuits and more particularly to the use of amorphous ternary aluminum nitride and boride alloy materials for diffusion barrier layers in such circuits. BACKGROUND OF THE INVENTION [0002] In semiconductor devices, it is common for the design to require interfaces of silicon and a metal such as aluminum or tungsten. For example, aluminum and tungsten are commonly used as the material of choice for electrical contacts, which contacts interface with electrically active areas made of doped silicon. It is also common in the fabrication of semiconductor devices to anneal the devices at elevated temperatures, such as 500° C. At these temperatures, the metal and silicon will rapidly interdiffuse into each other at the interface. Even at room temperature, the metal and silicon will interdiffuse over time. Such interdiffusion changes the semiconductive properties of the silicon and causes defective devices. [0003] Ca...

AI Technical Summary

Benefits of technology

These barrier layers effectively prevent interdiffusion and degradation of capacitor dielectrics and silicon / metal interfaces, enhancing the reliability of semiconductor devices during high-temperature fabrication processes and improving the performance of capacitors and other semiconductor components.

Problems solved by technology

Such interdiffusion changes the semiconductive properties of the silicon and causes defective devices.

Oxidation of the underlying Si results in decreased series capacitance, thus degrading the capacitor.

The conventional diffusion barriers for silicon / metal interfaces and capacitor dielectrics, while generally relatively effective at room temperature, can fail at more elevated temperatures.

Thus conventional diffusion barriers can create limits on the processes that can be used to fabricate a semiconductor device.

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