# US 9,040,391 B2 · Process for producing localised GeOI structures, obtained by germanium condensation

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- Number: US 9,040,391 B2
- Document ID: US9040391B2
- Status: Granted
- Kind: B2
- Application number: 12/539,713
- Filed: 2009-08-12
- Published: 2010-02-25
- Granted: 2015-05-26
- Earliest claimed: 2008-08-22
- Assignees: Commissariat a l'Energie Atomique
- Applicants: Jean-François Damlencourt; Benjamin Vincent
- Inventors: Jean-François Damlencourt; Benjamin Vincent
- Web page: https://patentgrep.com/patent/US9040391B2

## CPC

- H10P 14/665: {Porous materials}
- H10D 30/60: Insulated-gate field-effect transistors [IGFET] (H10D30/40 takes precedence)
- H10D 30/751: {having composition variations in the channel regions}
- H10D 64/01356: {the insulator being formed after the semiconductor body, the semiconductor being a Group IV material and not being silicon, e.g. Ge, SiGe or SiGeC (H10D64/01364, H10D64/01366 take precedence)}
- H10P 14/6308: {of Group IV semiconductors}
- H10P 14/6322: {Formation by thermal treatments (formation by plasma treatment H10P14/6319)}
- H10P 90/1906: {Preparing SOI wafers}
- H10W 10/181: {Semiconductor-on-insulator [SOI] isolation regions, e.g. buried oxide regions of SOI wafers}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

The invention relates to a process for making at least one GeOI structure by germanium condensation of a SiGe layer supported by a layer of silicon oxide. The layer of silicon oxide is doped with germanium, the concentration of germanium in the layer of silicon oxide being such that it lowers the flow temperature of the layer of silicon oxide below the oxidation temperature allowing germanium condensation of the SiGe layer.

## Claims

### Claim 1

A process for making at least one germanium-on-insulator structure, comprising the steps of:
forming a porous silicon germanium layer (32) on a substrate (31);
forming a first silicon layer (33) on the porous silicon germanium layer (32);
forming a layer of silicon germanium (34) intended to be enriched with germanium on the silicon layer (33);
oxidizing the porous silicon germanium layer (32), thereby forming a layer of silicon oxide (37) doped with germanium;
performing germanium condensation of the layer of silicon germanium (34) intended to be enriched with germanium, resulting in a layer (38) of silicon germanium enriched with germanium or with a layer of germanium on the layer of silicon oxide (37) doped with germanium.

### Claim 2 (depends on 1)

The process as claimed in claim 1, in which the concentration of germanium in the layer of silicon oxide (37) doped with germanium is such that the molar percentage of germanium dioxide relative to the composition of the layer of silicon oxide doped with germanium is between 4 and 13 m/o.

### Claim 3 (depends on 1, 2)

The process as claimed in claim 1 or 2, in which the porous silicon germanium layer is obtained by electrochemical attack of an initial layer of doped silicon germanium a solution of hydrofluoric acid.

### Claim 4 (depends on 1)

The process as claimed in claim 1, further comprising, before oxidizing the porous silicon germanium layer (32), the following steps:
formation of a second silicon layer (35) on the silicon germanium layer (34) intended to be enriched with germanium,
definition of at least one mesa in the stack constituted by the first silicon layer (33), the silicon germanium layer (34) intended to be enriched with germanium and the second silicon layer (35),
depositing protective spacers (36) on the flanks of the mesa.

### Claim 5 (depends on 4)

The process as claimed in claim 4, in which the protective spacers (36) are made of silicon nitride.