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Silicon-on-Insulator Systems Combined with Low-Temperature Silicon Epitaxy

Objective

The objective of this project was to obtain single crystalline layers of silicon-on-insulator (SOI), with thicknesses from 0.5micron to 30micron, for a variety of applications. The results are potentially applicable both to silicon-on-insulator, for high-performance integrated circuits, and as an alternative to dielectric isolation processing.
The objective of this project was to obtain single crystalline layers of silicon on insulator (SOI), with thicknesses from 0.5 micron to 30 micron, for a variety of applications.

The following results were achieved:
A new stripheater system was developed for the recrystallization of full wafers based on focused high pressure mercury lamps.
Recrystallization experiments were performed with focused laser beams and with the stripheater system.
A detailed study of the influence of all process parameters for both techniques was carried out.
Successful seeded and unseeded recrystallizations were performed, with both techniques leading to good quality material. Stripheater layers of between 0.5 micron and 10 micron were directly recrystallized; in both cases good electrical characteristics were obtained in test devices.
Epitaxial thickening of thin SOI layers was performed on limited as well as on large area structures.
A range of trench etching equipment was evaluated and a system purchased and installed. Very good trench etching was achieved up to a depth of 20 micron. Oxide polysilicon sandwich layers were evaluated as the best choice for trench filling.
The design of a combined insulator and epitaxy equipment for the photochemical deposition of insulators and silicon was completed. This technique was abandoned when it became clear that it was not commercially viable. The project demostrated that the methods used, based on lamp and laser beams, were technologically feasible but not, as yet, economically viable.
The following results were achieved:
-A new strip-heater system was developed for the recrystallisation of full wafers based on focused highpressure mercury lamps.
-Recrystallisation experiments were performed with focused laser beams and with the stripheater system.
-A detailed study of the influence of all process parameters for both techniques was carried out.
-Successful seeded and unseeded recrystallisations were performed, with both techniques leading to good quality material. Stripheater layers of between 0.5micron and 10micron were directly recrystallised; in both cases good electrical characteristics were obtained in test devices.
-Epitaxial thickening of thin SOIlayers was performed on limited as well as on large-area structures.
-A range of trench etching equipment was evaluated and a system purchased and installed. Very good trench etching was achieved up to a depth of 20micron. Oxidepolysilicon sandwich layers were evaluated as the best choice for trench filling.
-The design of a combined insulator and epitaxy equipment for the photochemical deposition of insulators and silicon was completed. This technique was abandoned when it became clear that it was not commercially viable.
The project demonstrated that the methods used, based on lamp and laser beams, were technologically feasible but not, as yet, economically viable. In particular, the lamp recrystallisation has been proven as the best approach for material synthesis if 0. 5 micron or thicker layers are required, such as for smart power and high voltage applications, whereas laser recrystallisation can be viewed as a viable method for 3D integration (see project245).

Coordinator

IMEC VZW
Address
Kapeldreef
3030 Heverlee
Belgium

Participants (2)

GEC-Marconi Materials Technology Ltd
United Kingdom
Address
Elstree Way
WD6 1RX Borehamwood
MIETEC NV
Belgium
Address
Westerring
9700 Oudenaarde