Method for chemical vapor deposition of silicon on to substrates for use in corrosive and vacuum environments

A substrate having at least a surface which has improved resistance to the effects of corrosion or the undesirable effects on a vacuum atmosphere, the substrate having at least a passivated surface comprising a silicon layer formed over the entire surface said silicon passivation layer being substantially free of silicon dust and having been formed according to the following steps:

• a) placing the substrate in an environment for treatment;
• b) dehydrating the surface of the substrate;
• c) evacuating the treatment environment;
• d) introducing a silicon hydride gas into the treatment environment to contact the substrate;
• e) heating the silicon hydride gas prior to, during or after the introduction of silicon hydride gas into the treatment environment;
• f) pressurizing the silicon hydride gas in the treatment environment;
• g) depositing a layer of silicon on a surface of the substrate;
• h) controlling one or more of the duration of the silicon depositing step, the pressure of the silicon hydride gas, and the presence of contaminants on the substrate surface to prevent the formation of silicon dust;
• i) cooling the substrate to a lower temperature and maintaining the substrate at a lower temperature for a period of time;
• j) purging the treatment environment with an inert gas to remove the silicon hydride gas;
• k) cycling the substrate through steps c) through j) for at least one cycle;
• l) evacuating the treatment environment;
• and,
• m) cooling the substrate to room temperature.

A method of passivating a surface of a substrate to protect the surface against corrosion or the undesirable effects on a vacuum atmosphere, comprising the steps of:

• a) placing the substrate in an environment for treatment;
• b) dehydrating the surface of the substrate;
• c) evacuating treatment the environment;
• d) introducing a silicon hydride gas into the treatment environment to contact the substrate;
• e) heating the silicon hydride gas in the treatment environment;
• f) pressurizing the silicon hydride gas in the treatment environment;
• g) depositing a layer of silicon on a surface of the substrate;
• h) controlling one or more of the duration of the silicon depositing step, the pressure of the silicon hydride gas, and the presence of contaminants on the substrate surface to prevent the formation of silicon dust;
• i) cooling the substrate to a lower temperature and maintaining the substrate at a lower temperature for a period of time;
• j) purging the treatment environment with an inert gas to remove the silicon hydride gas;
• k) cycling the substrate through steps c) through j) for at least one cycle;
• l) evacuating the treatment environment;
• and,
• m) cooling the substrate to room temperature;
• said lower temperature to which the substrate is cooled in step i) is from about 50° C. to 400° C.;
• said period of time at which the substrate is maintained at a lower temperature is from about 5 to 100 minutes;
• said dehydration step comprising heating the substrate to a temperature in the range of from about 300° C. to 600° C. for a duration of from about 10 to 240 minutes;
• including the step of heating the substrate in an inert gas or in a vacuum;
• said silicon hydride gas being selected from the group comprising SiH4 and SinHn+2;
• said silicon hydride gas being heated to a temperature approximately equal to the gas's decomposition temperature;
• said silicon hydride gas being heated to a temperature in the range of from about 300° C. to 600° C.;
• said silicon hydride gas being pressurized to a pressure in the range of from about 0.1 torr to 2500 torr;
• said layer of silicon being deposited on the substrate surface for a period in the range of from about 1 to 480 minutes.