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Binary metal alloy formation on III-V CMOS semiconductor: Oxygen gettering and diffusion control by Ti-Ni on InGaAs

IP.com Disclosure Number: IPCOM000236978D
Publication Date: 2014-May-23
Document File: 2 page(s) / 116K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to form metal alloy with Indium Gallium Arsenide (InGaAs) that achieves self-aligned metal contact without the residual oxide problem at the interface. The novel solution is the application of a Titanium Nickel (Ti-Ni) binary metal to form an Ni_InGaAs layer with an Oxygen (O) gettering layer by Ti, which absorbs most of O in the metal system.

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Binary metal alloy formation on III - -V CMOS semiconductor

V CMOS semiconductor : :

Oxygen gettering and

Oxygen gettering and

diffusion control by Ti - -Ni on InGaAs

Ni on InGaAs

Formation of metal alloy with Indium Gallium Arsenide (InGaAs) has been problematic, especially for self-aligned metal contact to achieve selective etch. In addition, residual native oxide formation on the InGaAs surface hinders high quality alloy formation , leading to high contact resistivity and high sheet resistance. Therefore, a method is needed to achieve self-aligned metal contact without the residual oxide problem at the interface.

The conventional process follows:


1. Pre-cleaning of InGaAs by Wet chemical
2. Ar presputtering of InGaAs

3. Ni deposition followed by TiN
4. RTA for alloy formation
5. Selective TiN strip

Figure 1: Conventional process

The conventional process experiences rapid residual oxide formation on the surface of InGaAs and has a fast sputtering rate of InGaAs by Argon (Ar) pre-sputtering, which leads to excessive InGaAs loss.

The novel solution is the application of a Titanium Nickel (Ti-Ni) binary metal to form an Ni_InGaAs layer with an Oxygen (O) gettering layer by Ti. Ti absorbs most of O in the metal system. This improves resistivity and helps control Ni diffusion.

With this solution:

• Ni can be 3~10nm • Ti thickness can be 1nm ~3nm
• TiN capping can be 10~20nm

Figure 2: New scheme

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Page 02 of 2

Figure 3: Embodiment of the solution

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