Low temperature processes for making electronic device structures
First Claim
1. A process for depositing layers of silicon nitride at low temperatures on a plastic substrate, said process comprising:
- encapsulating said plastic substrate with an electrically-insulating protective coating;
placing said plastic substrate in a plasma chemical vapor deposition reactor, reducing a pressure in said reactor to about 0.6 Torr. bringing said plastic substrate to a temperature of about 125°
C., flowing a gas mixture comprising helium, nitrogen, ammonia and silane through said reactor, and creating a plasma within said reactor so as to disassociate said gas mixture and thereby deposit a layer of amorphous silicon nitride on said protective coating, wherein said creating a plasma comprises using radio frequency energy having power/area in a range of about 0.03 to about 0.1 Watts/cm2, and wherein said amorphous silicon nitride layer has a leakage current density of less than about 1×
10−
3 Amps/cm2 and a breakdown electric field of greater than about 5 MV/cm.
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Accused Products
Abstract
A thin film transistor is described incorporating a gate electrode, a gate insulating layer, a semiconducting channel layer deposited on top of the gate insulating layer, an insulating encapsulation layer positioned on the channel layer, a source electrode, a drain electrode and a contact layer beneath each of the source and drain electrodes and in contact with at least the channel layer, all of which are situated on a plastic substrate. By enabling the use of plastics having low glass transition temperatures as substrates, the thin film transistors may be used in large area electronics such as information displays and light sensitive arrays for imaging which are flexible, lighter in weight and more impact resistant than displays fabricated on traditional glass substrates. The thin film transistors are useful in active matrix liquid crystal displays where the plastic substrates are transparent in the visible spectrum. Enablement of the use of such plastics is by way of the use of polymeric encapsulation films to coat the surfaces of the plastic substrates prior to subsequent processing and the use of novel low temperature processes for the deposition of thin film transistor structures.
42 Citations
12 Claims
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1. A process for depositing layers of silicon nitride at low temperatures on a plastic substrate, said process comprising:
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encapsulating said plastic substrate with an electrically-insulating protective coating;
placing said plastic substrate in a plasma chemical vapor deposition reactor, reducing a pressure in said reactor to about 0.6 Torr. bringing said plastic substrate to a temperature of about 125°
C.,flowing a gas mixture comprising helium, nitrogen, ammonia and silane through said reactor, and creating a plasma within said reactor so as to disassociate said gas mixture and thereby deposit a layer of amorphous silicon nitride on said protective coating, wherein said creating a plasma comprises using radio frequency energy having power/area in a range of about 0.03 to about 0.1 Watts/cm2, and wherein said amorphous silicon nitride layer has a leakage current density of less than about 1×
10−
3 Amps/cm2 and a breakdown electric field of greater than about 5 MV/cm.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification