Semiconductor structure having aluminum oxynitride film on germanium layer and method of fabricating the same

Patent metadata

Field	Value
Publication number	US-9306026-B2
Application number	US-201514630198-A
Country	US
Kind code	B2
Filing date	Feb 24, 2015
Priority date	Aug 24, 2012
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

A semiconductor structure includes: a germanium layer 30 ; and an aluminum oxynitride film 32 that is formed on the germanium layer, wherein: an EOT of the aluminum oxynitride film is 2 nm or less; Cit/Cacc is 0.4 or less; on a presumption that Au acting as a metal film is formed on the aluminum oxynitride film, the Cit is a capacitance value between the germanium layer and the metal film at a frequency of 1 MHz in a case where a voltage of the metal film with respect to the germanium layer is applied to an inversion region side by 0.5 V; and the Cacc is a capacitance value between the germanium layer and the metal film in an accumulation region.

First claim

The invention claimed is:

1. A semiconductor structure comprising:
a germanium layer; and
an aluminum oxynitride film that is formed on the germanium layer,
wherein an EOT of the aluminum oxynitride film is 2 nm or less,
wherein at an interface between the germanium layer and the aluminum oxynitride film:
Cit/Cacc is 0.4 or less;
wherein if a metal film comprising gold is formed on the aluminum oxynitride film, the Cit is a capacitance value between the germanium layer and the metal film at a frequency of 1 MHz in a case where a voltage of the metal film with respect to the germanium layer is applied to an inversion region side by 0.5 V and the Cacc is a capacitance value between the germanium layer and the metal film in an accumulation region;
the Cit/Cacc is less than 0.05×T when an initial thickness (nm) of the aluminum oxynitride film before the thermal process is the T.

2. The semiconductor structure of claim 1 , further comprising at least one of a germanium oxynitride film and a compound film of a germanium oxynitride and an aluminum oxynitride, said at least one of the germanium oxynitride film and the compound film being formed between the germanium layer and the aluminum oxynitride film.

3. The semiconductor structure of claim 1 , wherein the EOT of the aluminum oxynitride film is 1 nm or less.

4. The semiconductor structure of claim 1 , further comprising a gate electrode that is formed on the aluminum oxynitride film.

5. A method of fabricating a semiconductor structure comprising:
a process of forming an aluminum oxynitride film on a germanium layer;
a process of performing a thermal process to the aluminum oxynitride film in an inert gas atmosphere at a thermal process temperature in a pressure in which a pressure of the inert gas at a room temperature is higher than an atmospheric pressure,
wherein the thermal process temperature is higher than a temperature during forming the aluminum oxynitride film.

6. The method of claim 5 , wherein the inert gas is a nitrogen gas.

7. The method of claim 5 , wherein:
the thermal process temperature of the process of performing the thermal process is 400 degrees C. or more; and
the pressure is 2 atmospheres or more.

8. The method of claim 5 , wherein:
the thermal process temperature of the process of performing the thermal process is 400 degrees C. or more; and
the pressure is 10 atmospheres or more.

9. The method of claim 5 , further comprising a process of forming a gate electrode on the aluminum oxynitride film.

10. The method of claim 5 , further comprising a process of forming a gate electrode on the aluminum oxynitride film,
wherein:
the inert gas is a nitrogen gas;
the thermal process temperature of the process of performing the thermal process is 400 degrees C. or more; and
the pressure is 10 atmospheres or more.

Assignees

• Japan Science & Tech Agency

Inventors

• Toriumi Akira
• Tabata Toshiyuki

Classifications

• H10P95/00

  Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass · CPC title

• H10P14/69391

  the material containing aluminium, e.g. Al2O3 · CPC title

• H10P14/6529

  by exposure to a gas or vapour · CPC title

• H10P14/6516

  of treatments performed after formation of the materials · CPC title

• H10P14/6329

  using physical ablation of a target, e.g. physical vapour deposition or pulsed laser deposition · CPC title