Control of amount and uniformity of oxidation at the interface of an emitter region of a monocrystalline silicon wafer and a polysilicon layer formed by chemical vapor deposition

A method of fabricating a semiconductor integrated circuit device including poly-emitter bipolar transistors, the method comprising:

• forming an emitter region on a surface of a monocrystalline silicon wafer;
• and
• controlling an amount and uniformity of distribution of oxygen atoms at an interface between the emitter region of the surface of the monocrystalline silicon wafer and a layer of polysilicon subsequently deposited thereon via low pressure chemical vapor deposition, and comprising
• cleaning and passivating the surface of the monocrystalline silicon wafer with hydrofluoric acid,
• rinsing and drying the monocrystalline silicon wafer,
• loading the monocrystalline silicon wafer inside a reactor for chemical vapor deposition,
• evacuating the reactor at a vacuum between 0.1 Pa and 15000 Pa,
• passivating the surface of the monocrystalline silicon wafer with hydrogen at a vacuum between 0.1 Pa and 60000 Pa and at a temperature between 500 and 1200° C., for a time between 0.1 and 120 minutes,
• exposing the passivated surface of the monocrystalline silicon wafer to an atmosphere of nitrogen protoxide (N2O) for a time between 0.1 and 120 minutes at a vacuum between 0.1 Pa and 60000 Pa and at a temperature between 700 and 1000°C.,
• lowering a temperature inside the reactor until reaching a value between 500° C. and 800° C. before starting the deposition of polysilicon,
• raising the temperature inside the reactor and depositing the polysilicon, and
• keeping an atmosphere of a gas in the reactor during the evacuating and heating, the gas comprising at least one of nitrogen, argon, and helium.

A method of depositing a layer of polysilicon on a surface of a monocrystalline silicon wafer, the method comprising:

• loading the monocrystalline silicon wafer inside a chemical vapor deposition reactor;
• evacuating the reactor at a vacuum between 0.1 Pa and 15000 Pa;
• treating the surface of the monocrystalline silicon wafer with hydrogen at a vacuum between 0.1 Pa and 60000 Pa and at a temperature between 500 and 1200° C., for a time between 0.1 and 120 minutes;
• exposing the passivated surface of the monocrystalline silicon wafer to an atmosphere of nitrogen protoxide (N2O) for a time between 0.1 and 120 minutes at a vacuum between 0.1 Pa and 60000 Pa and at a temperature between 700 and 1000° C.;
• and raising the temperature inside the reactor and depositing the polysilicon.

A method of fabricating a semiconductor integrated circuit device including a poly-emitter bipolar transistor, the method comprising:

• forming an emitter region on a surface of a monocrystalline silicon wafer;
• loading the monocrystalline silicon wafer inside a chemical vapor deposition reactor;
• evacuating the reactor at a vacuum between 0.1 Pa and 15000 Pa;
• treating the surface of the monocrystalline silicon wafer with hydrogen at a vacuum between 0.1 Pa and 60000 Pa and at a temperature between 500 and 1200° C., for a time between 0.1 and 120 minutes;
• exposing the passivated surface of the monocrystalline silicon wafer to an atmosphere of nitrogen protoxide (N2O) for a time between 0.1 and 120 minutes at a vacuum between 0.1 Pa and 60000 Pa and at a temperature between 700 and 1000° C.;
• and
• raising the temperature inside the reactor and depositing polysilicon.