Process of forming silicon nitride (SiN) film and semiconductor device providing SiN film
AssigneeSumitomo Electric Industries, Ltd.
InventorKazuhide Sumiyoshi
Life of this patent
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Abstract
A low pressure chemical vapor deposition (LPCVD) technique for nitride semiconductor materials includes steps of: setting a temperature in a furnace to be 750 to 900° C.; substituting an atmosphere in the furnace to ammonia (NH3); depositing a SiN film at an initial pressure by supplying di-chloro-silane (SiH2Cl2); and subsequently depositing the SiN film at a deposition pressure that is higher than the initial pressure. The invention has a feature that the initial pressure is at least higher than 60% of the deposition pressure.
Claims16
A process of depositing a silicon nitride (SiN) film on a nitride semiconductor layer by a low pressure chemical vapor deposition (LPCVD) technique, the process comprising steps of:
- setting a temperature in a LPCVD furnace to be higher than 750° C. but lower than 900° C.;
- substituting an atmosphere in the LPCVD furnace to an ammonia NH3 atmosphere;
- setting a pressure in the LPCVD furnace to be a first pressure by flowing only ammonia (NH3);
- depositing the SiN film by supplying di-chloro-silane (SiH2Cl2) at the first pressure;
- and
- subsequently depositing the SiN film by changing the pressure to a second pressure that is higher than the first pressure,
- wherein the first pressure is 60% or more of the second pressure.
A process of forming a nitride semiconductor device comprising steps of:
- forming a semiconductor stack on a substrate, the semiconductor stack including nitride semiconductor layers;
- forming a passivation film made of silicon nitride (SiN) on the semiconductor stack by a low pressure chemical vapor deposition (LPCVD) technique;
- forming electrodes of a source and a drain on the semiconductor stack by forming respective openings in the passivation film;
- and
- forming an electrode of a gate on the semiconductor stack by forming an opening in the passivation film,
- wherein the step of forming the passivation film includes steps of:
- setting a temperature in a LPCVD furnace to be higher than 750° C. but lower than 900° C.;
- substituting an atmosphere in the LPCVD furnace to an ammonia (NH3) atmosphere;
- setting a pressure in the LPCVD furnace to be a first pressure by flowing only ammonia (NH3);
- depositing the SiN film by supplying di-chloro-silane (SiH2Cl2) at the first pressure;
- and
- subsequently depositing the SiN film by changing the pressure in a second pressure that is higher than the first pressure,
- wherein the first pressure is 60% or higher of the second pressure.
Dependencies are inferred from the claim text.