Semiconductor processing method of providing a roughened polysilicon film and a capacitor construction

A semiconductor processing method, comprising:

• placing a semiconductive substrate within a chemical vapor deposition reactor;
• while the substrate is within the chemical vapor deposition reactor, chemical vapor depositing an in situ conductively doped amorphous silicon layer onto the substrate at a first temperature, the first temperature being below 600.degree. C., the doped amorphous silicon layer having an outer surface of a first degree of roughness;
• within the chemical vapor deposition reactor and after depositing the doped amorphous silicon layer, raising the substrate temperature at a first selected rate to a higher silicon seeding temperature;
• with the substrate at the seeding temperature, depositing a discontinuous layer of silicon seeds atop the doped amorphous silicon layer;
• within the chemical vapor deposition reactor and after depositing the discontinuous layer of silicon seeds atop the doped amorphous silicon layer, providing the substrate temperature at an annealing second temperature, the annealing second temperature being from 550.degree. C. to 950.degree. C.;
• and
• maintaining the substrate at the annealing second temperature for a period of time sufficient to convert at least an outer portion of the doped amorphous layer into a doped polysilicon layer having an outer surface of a second degree of roughness, the second degree of roughness being greater than the first degree of roughness, the substrate not being removed from the reactor nor exposed to oxidizing conditions between the time of deposition of the doped amorphous silicon layer and its conversion to polysilicon.

A semiconductor processing method of forming a capacitor, comprising:

• providing a semiconductive monocrystalline silicon substrate,
• forming a diffusion region within the semiconductive substrate;
• forming an insulative layer over the semiconductive substrate;
• forming an opening through the insulative layer, the diffusion region being exposed within said opening;
• after forming the opening, placing the semiconductive substrate in a chemical vapor deposition reactor;
• while the substrate is within the chemical vapor deposition reactor, chemical vapor depositing an in situ conductively doped amorphous silicon layer over the insulative layer and within the opening at a first temperature, the first temperature being below 600.degree. C., the doped amorphous silicon layer having an outer surface of a first degree of roughness, the doped amorphous layer contacting the diffusion region;
• within the chemical vapor deposition reactor and after depositing the doped amorphous silicon layer, raising the substrate temperature at a selected rate to a higher annealing second temperature, the annealing second temperature being from 550.degree. C. to 950.degree. C.;
• maintaining the substrate at the annealing second temperature for a period of time sufficient to convert at least an outer portion of the doped amorphous layer into a doped polysilicon layer having an outer surface of a second degree of roughness, the second degree of roughness being greater than the first degree of roughness, the substrate not being removed from the reactor nor exposed to oxidizing conditions between the time of deposition of the doped amorphous silicon layer and its conversion to polysilicon;
• after converting the at least an outer portion of the doped amorphous layer into a doped polysilicon layer, polishing the polysilicon layer to remove the polysilicon layer from over the insulative layer and to form a polished polysilicon layer within the opening;
• forming a dielectric layer over the polished polysilicon layer and over the insulative layer;
• and
• forming an outer capacitor plate over the dielectric layer;
• the outer capacitor plate, dielectric layer and polysilicon layer together comprising a capacitor.

A semiconductor processing method of forming a capacitor, comprising:

• providing a semiconductive monocrystalline silicon substrate,
• forming a diffusion region within the semiconductive substrate;
• forming an insulative layer over the semiconductive substrate;
• forming an opening through the insulative layer, the diffusion region being exposed within said opening;
• after forming the opening, placing the semiconductive substrate in a chemical vapor deposition reactor;
• while the substrate is within the chemical vapor deposition reactor, chemical vapor depositing an in situ conductively doped amorphous silicon layer over the substrate within the reactor at a first temperature, the first temperature being below 600.degree. C., the doped amorphous silicon layer having an outer surface of a first degree of roughness;
• within the chemical vapor deposition reactor and after depositing the doped amorphous silicon layer, raising the substrate temperature at a first selected rate to a higher silicon seeding temperature;
• with the substrate at the seeding temperature, depositing a discontinuous layer of silicon seeds atop the doped amorphous silicon layer;
• within the chemical vapor deposition reactor and after depositing the discontinuous layer of silicon seeds atop the doped amorphous silicon layer, providing the substrate temperature at an annealing second temperature, the annealing second temperature being from 550.degree. C. to 950.degree. C.;
• maintaining the substrate at the annealing second temperature for a period of time sufficient to convert at least an outer portion of the doped amorphous layer into a doped polysilicon layer having an outer surface of a second degree of roughness, the second degree of roughness being greater than the first degree of roughness, the substrate not being removed from the reactor nor exposed to oxidizing conditions between the time of deposition of the doped amorphous silicon layer and its conversion to polysilicon;
• after converting the at least an outer portion of the doped amorphous layer into a doped polysilicon layer, polishing the polysilicon layer to remove the polysilicon layer from over the insulative layer and to form a polished polysilicon layer within the opening;
• forming a dielectric layer over the polished polysilicon layer and over the insulative layer;
• and
• forming an outer capacitor plate over the dielectric layer;
• the outer capacitor plate, dielectric layer and polysilicon layer together comprising a capacitor.