Method of providing a silicon film having a roughened outer surface

Claim 1

A method of providing a silicon film having a roughened outer surface atop a semiconductor wafer, the method comprising the following steps: placing the semiconductor wafer having a surface into a plasma enhanced RF powered chemical vapor deposition reactor; and plasma enhanced chemical vapor depositing a layer of silicon over the wafer surface by providing quantities of a silicon source gas, a carrier gas, and TiCl 4 to the reactor, an atomic ratio of the quantities of the silicon source gas and the TiCl 4 being greater than or equal to 4 at the wafer surface; and by maintaining the reactor at an RF power, a pressure and a temperature; the RF power being supplied at a frequency of at least 5 MHz, the quantities of the silicon source gas, the RF power, the temperature and the pressure being effective to produce a predominately silicon film having the outer surface, the quantity of the TiCl 4 being ineffective to produce a predominately titanium silicide film.

Claim 2

A method of providing a silicon film having a roughened outer surface atop a semiconductor wafer, the method comprising the following steps: placing the semiconductor wafer having a surface into a plasma enhanced RF powered chemical vapor deposition reactor; and plasma enhanced chemical vapor depositing a layer of silicon over the wafer surface by providing quantities of a silicon source gas, a carrier gas, and TiCl 4 to the reactor, an atomic ratio of the quantities of the silicon source gas and the TiCl 4 being greater than or equal to 4 at the wafer surface; and by maintaining the reactor at an RF power, a pressure and a temperature; the RF power being supplied at a frequency of at least 5 MHz, the quantities of the silicon source gas, the RF power, the temperature and the pressure being effective to produce a predominately silicon film having the outer surface, the quantity of the TiCl 4 being ineffective to produce a predominately titanium silicide film.

Claim 10

A method of providing a polysilicon film having a roughened outer surface atop a semiconductor wafer, the method comprising the following steps: placing the semiconductor wafer having a surface into a plasma enhanced RF powered chemical vapor deposition reactor; plasma enhanced chemical vapor depositing a layer of amorphous silicon over the wafer surface by providing quantities of a silicon source gas, a carrier gas, and TiCl 4 to the reactor, an atomic ratio of the quantities of the silicon source gas and the TiCl 4 being greater than or equal to 4 at the wafer surface; and by maintaining the reactor at an RF power, a pressure and a temperature; the RF power being supplied at a frequency of at least 5 MHz, the quantities of the silicon source gas, the RF power, the temperature and the pressure being effective to produce a predominately amorphous silicon film having the outer surface, the quantity of the TiCl 4 being ineffective to produce a predominately titanium silicide film; and annealing the wafer to render the amorphous silicon polycrystalline.

Claim 11

A method of providing a polysilicon film having a roughened outer surface atop a semiconductor wafer, the method comprising the following steps: placing the semiconductor wafer having a surface into a plasma enhanced RF powered chemical vapor deposition reactor; plasma enhanced chemical vapor depositing a layer of amorphous silicon over the wafer surface by providing quantities of a silicon source gas, a carrier gas, and TiCl 4 to the reactor, an atomic ratio of the quantities of the silicon source gas and the TiCl 4 being greater than or equal to 4 at the wafer surface; and by maintaining the reactor at an RF power, a pressure and a temperature; the RF power being supplied at a frequency of at least 5 MHz, the quantities of the silicon source gas, the RF power, the temperature and the pressure being effective to produce a predominately amorphous silicon film having the outer surface, the quantity of the TiCl 4 being ineffective to produce a predominately titanium silicide film; and annealing the wafer to render the amorphous silicon polycrystalline.

Claim 18

A method of providing a silicon film having a roughened outer surface atop a semiconductor wafer, the method comprising the following sequential steps: placing the semiconductor wafer having a surface into a plasma enhanced RF powered chemical vapor deposition reactor; plasma enhanced chemical vapor depositing a first layer of silicon over the wafer surface by feeding quantities of a silicon source gas, a carrier gas, and TiCl 4 to the reactor, an atomic ratio of the quantities of the silicon source gas and the TiCl 4 being greater than or equal to 4 at the wafer surface; and by maintaining the reactor at an RF power, a pressure and a temperature; the RF power being supplied at a frequency of at least 5 MHz, the quantities of the silicon source gas, the RF power, the temperature and the pressure being effective to produce a first predominately silicon film having a first outer surface, the quantity of the TiCl 4 being effective to induce roughness into the first outer silicon surface as compared to an outer silicon surface prepared under identical conditions but for introduction of the TiCl 4 but the quantity of the TiCl 4 being ineffective to produce a predominately titanium silicide film; and ceasing to feed the TiCl 4 to the reactor while continuing to the silicon source gas to the reactor, and maintaining the RF power, the pressure and the temperature at quantities effective to deposit a second layer of silicon atop the first outer surface of the first layer of silicon, the second layer of silicon having a second outer surface, the first outer surface at least in part inducing roughness into the second outer surface.

Claim 19

A method of providing a silicon film having a roughened outer surface atop a semiconductor wafer, the method comprising the following sequential steps: placing the semiconductor wafer having a surface into a plasma enhanced RF powered chemical vapor deposition reactor; plasma enhanced chemical vapor depositing a first layer of silicon over the wafer surface by feeding quantities of a silicon source gas, a carrier gas, and TiCl 4 to the reactor, an atomic ratio of the quantities of the silicon source gas and the TiCl 4 being greater than or equal to 4 at the wafer surface; and by maintaining the reactor at an RF power, a pressure and a temperature; the RF power being supplied at a frequency of at least 5 MHz, the quantities of the silicon source gas, the RF power, the temperature and the pressure being effective to produce a first predominately silicon film having a first outer surface, the quantity of the TiCl 4 being effective to induce roughness into the first outer silicon surface as compared to an outer silicon surface prepared under identical conditions but for introduction of the TiCl 4 but the quantity of the TiCl 4 being ineffective to produce a predominately titanium silicide film; and ceasing to feed the TiCl 4 to the reactor while continuing to the silicon source gas to the reactor, and maintaining the RF power, the pressure and the temperature at quantities effective to deposit a second layer of silicon atop the first outer surface of the first layer of silicon, the second layer of silicon having a second outer surface, the first outer surface at least in part inducing roughness into the second outer surface.

Claim 28

A method of providing a polysilicon film having a roughened outer surface atop a semiconductor wafer, the method comprising the following sequential steps: placing the semiconductor wafer having a surface into a plasma enhanced RF powered chemical vapor deposition reactor; plasma enhanced chemical vapor depositing a first layer of amorphous silicon over the wafer surface by feeding quantities of a silicon source gas, a carrier gas, and TiCl 4 to the reactor, an atomic ratio of the quantities of the silicon source gas and the TiCl 4 being greater than or equal to 4 at the wafer surface; and by maintaining the reactor at an RF power, a pressure and a temperature; the RF power being supplied at a frequency of at least 5 MHz, the quantities of the silicon source gas, the RF power, the temperature and the pressure being effective to produce a first predominately amorphous silicon film having a first outer surface, the quantity of the TiCl 4 being effective to induce roughness into the first outer amorphous silicon surface as compared to an outer amorphous silicon surface prepared under identical conditions but for introduction of the TiCl 4 but the quantity of the TiCl 4 being ineffective to produce a predominately titanium silicide film; ceasing to feed the TiCl 4 to the reactor while continuing to feed the silicon source gas to the reactor, and maintaining the RF power, the pressure and the temperature at quantities effective to deposit a second layer of silicon atop the first outer surface of the first layer of silicon, the second layer of silicon having a second outer surface, the first amorphous outer surface at least in part inducing roughness into the second outer surface; and annealing the wafer to render the first amorphous film polycrystalline.

Claim 29

A method of providing a polysilicon film having a roughened outer surface atop a semiconductor wafer, the method comprising the following sequential steps: placing the semiconductor wafer having a surface into a plasma enhanced RF powered chemical vapor deposition reactor; plasma enhanced chemical vapor depositing a first layer of amorphous silicon over the wafer surface by feeding quantities of a silicon source gas, a carrier gas, and TiCl 4 to the reactor, an atomic ratio of the quantities of the silicon source gas and the TiCl 4 being greater than or equal to 4 at the wafer surface; and by maintaining the reactor at an RF power, a pressure and a temperature; the RF power being supplied at a frequency of at least 5 MHz, the quantities of the silicon source gas, the RF power, the temperature and the pressure being effective to produce a first predominately amorphous silicon film having a first outer surface, the quantity of the TiCl 4 being effective to induce roughness into the first outer amorphous silicon surface as compared to an outer amorphous silicon surface prepared under identical conditions but for introduction of the TiCl 4 but the quantity of the TiCl 4 being ineffective to produce a predominately titanium silicide film; ceasing to feed the TiCl 4 to the reactor while continuing to feed the silicon source gas to the reactor, and maintaining the RF power, the pressure and the temperature at quantities effective to deposit a second layer of silicon atop the first outer surface of the first layer of silicon, the second layer of silicon having a second outer surface, the first amorphous outer surface at least in part inducing roughness into the second outer surface; and annealing the wafer to render the first amorphous film polycrystalline.