Semiconductor device and method of fabricating same
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsHongyong Zhang, Satoshi Teramoto
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Abstract
There are disclosed TFTs having improved reliability. An interlayer dielectric film forming the TFTs is made of a silicon nitride film. Other interlayer dielectric films are also made of silicon nitride. The stresses inside the silicon nitride films forming these interlayer dielectric films are set between −5×109 and 5×109 dyn/cm2. This can suppress peeling of the interlayer dielectric films and difficulties in forming contact holes. Furthermore, release of hydrogen from the active layer can be suppressed. In this way, highly reliable TFTs can be obtained.
Claims10
A semiconductor device comprising:
- a substrate having an insulating surface;
- a thin film transistor formed on the insulating surface, the thin film transistor having a semiconductor film comprising crystalline silicon;
- a first interlayer insulating film comprising silicon nitride formed over the thin film transistor;
- a source electrode formed over the first interlayer insulating film and electrically connected to the semiconductor film;
- a second interlayer insulating film comprising silicon nitride formed over the first interlayer insulating film and the source electrode;
- and
- a drain electrode formed over the second interlayer insulating film and electrically connected to the semiconductor film,
- wherein each of the first and second interlayer insulating films has an internal stress oriented in compressive direction and a variation of the internal stress in each of the first and second interlayer insulating films is within a range of ±50%.
A semiconductor device comprising:
- a substrate having an insulating surface;
- a thin film transistor formed on the insulating surface, the thin film transistor having a semiconductor film comprising crystalline silicon;
- a first interlayer insulating film comprising silicon nitride formed over the thin film transistor;
- a source electrode formed over the first interlayer insulating film and electrically connected to the semiconductor film;
- a second interlayer insulating film comprising silicon nitride formed over the first interlayer insulating and the source electrode;
- and
- a drain electrode formed over the second interlayer insulating film and electrically connected to the semiconductor film,
- wherein the absolute value of an internal stress of first and second interlayer insulating films is in 5×109 dyn/cm2 or less.
A semiconductor device comprising:
- a substrate having an insulating surface;
- a thin film transistor formed on the insulating surface, the thin film transistor having a semiconductor film comprising crystalline silicon;
- a first interlayer insulating film comprising silicon nitride formed over the thin film transistor;
- a source electrode formed over the first interlayer insulating film and electrically connected to the semiconductor film;
- a second interlayer insulating film comprising silicon nitride formed over the first interlayer insulating film and the source electrode;
- a drain electrode formed over the second interlayer insulating film and electrically connected to the semiconductor film;
- a third interlayer insulating film over the source and drain electrode;
- and
- a pixel electrode formed over the third interlayer insulating film and connected to the drain electrode,
- wherein an etching rate of the second interlayer insulating film is larger than an etching rate of the first interlayer insulating film, and
- wherein each of the first and second interlayer insulating films has an internal stress acting the same direction.
Dependencies are inferred from the claim text.