Method for fabricating a cavity structure, for fabricating a cavity structure for a semiconductor structure and a semiconductor microphone fabricated by the same

A method for fabricating a semiconductor structure comprising:

• providing an interstage semiconductor structure that comprises a semiconductor material and a sacrificial material;
• and
• removing the sacrificial material from the interstage semiconductor structure to form the semiconductor structure,
• wherein the sacrifical material is made of carbon deposited at a temperature between 700° C. to 900° C.

A method for forming a cavity structure for a semiconductor device, the method comprising:

• applying a chemical vapor deposition (CVD) to deposit a carbon layer on a first layer, wherein the chemical vapor deposition is performed at a temperature between 700° C. and 900° C. and at a pressure between 1 Torr and 500 Torr;
• covering at least partially the carbon layer with a second layer so that the cavity structure is defined by an overlapping part of the second layer covering the carbon layer and the first layer;
• and
• removing the carbon layer at least in the overlapping part by dry etching so that the cavity structure is formed.

A method for forming a cavity structure for a semiconductor microphone, the method comprising:

• depositing a conductive first membrane layer on a main surface of a semiconductor substrate;
• using chemical vapor deposition (CVD), depositing a carbon layer on the first membrane layer, wherein the chemical vapor deposition is performed at a temperature between 700° C. and 900° C. and at a pressure between 1 Torr to 500 Torr;
• covering at least partially the carbon layer with a conductive second membrane layer so that the cavity structure for the semiconductor microphone is defined by an overlapping part of the second membrane layer covering the carbon layer and the first membrane layer;
• and
• removing the carbon layer at least in the overlapping part by dry etching the carbon layer via openings so that the cavity structure for the semiconductor microphone arranged between the first and the second conductive membrane layers is formed.