Methods of forming silicon dioxide layers, and methods of forming trench isolation regions

A method of forming a silicon dioxide layer, comprising:

• forming a high density plasma having a density of at least 1010 ions/cm3 proximate a substrate;
• flowing gases into the plasma, at least some of the gases forming silicon dioxide;
• depositing the silicon dioxide formed from the gases over the substrate at a deposition rate;
• and
• while depositing the silicon dioxide, maintaining a temperature of the substrate at greater than or equal to about 500° C. and etching the deposited silicon dioxide with the plasma at an etch rate, a ratio of the deposition rate to the etch rate being at least about 6:1.

A method of forming silicon dioxide comprising:

• forming era opening extending into a substrate;
• thermally oxidizing the substrate to form a first layer of silicon dioxide within the opening;
• and
• forming a second layer of silicon dioxide on and in contact with the first layer within the opening, the forming of the second layer of silicon dioxide comprising:
• forming a high density plasma proximate the substrate;
• flowing gases into the plasma, at least some of the gases forming silicon dioxide;
• maintaining the substrate at a temperature of at least about 500° C.;
• and
• while maintaining the substrate at said temperature, depositing the silicon dioxide formed from the gases within the opening.

A method of forming a shallow trench isolation region comprising:

• forming an opening extending into a substrate;
• forming a first layer of silicon dioxide within the opening;
• and
• forming a second layer of silicon dioxide over the first layer within the opening, material from the first and second layers within the opening being comprised by the shallow trench isolation region and the forming of the second layer of silicon dioxide comprising:
• forming a high density plasma proximate the substrate;
• flowing gases into the plasma, at least some of the gases forming silicon dioxide;
• maintaining the substrate at a temperature of at least about 500° C.;
• and
• while maintaining the substrate at said temperature, depositing the silicon dioxide formed from the gases within the opening.

A method of forming a shallow trench isolation region comprising:

• forming an opening extending into a substrate that comprises steps at peripheries of the opening;
• thermally oxidizing the substrate to form a first layer of silicon dioxide within the opening;
• and
• forming a second layer of silicon dioxide within the opening to fill the opening, the shallow trench isolation region consisting of material from the first and second layers within the opening end the forming of the second layer of silicon dioxide comprising:
• forming a high density plasma proximate the substrate;
• flowing gases into the plasma, at least some of the gases forming silicon dioxide;
• maintaining the substrate at a temperature of at least about 500° C.;
• and
• while maintaining the substrate at said temperature, depositing the silicon dioxide formed from the gases within the opening, the depositing achieving better step coverage than would otherwise occur at a lower temperature less than or equal to 300° C.

A method of forming a shallow trench isolation region, comprising:

• forming a pad oxide layer over a semiconductive substrate;
• forming a silicon nitride layer over the pad oxide layer;
• forming an opening extending through the silicon nitride layer, through the pad oxide layer, and into the substrate;
• forming a first layer of silicon dioxide within the opening;
• and
• forming a second layer of silicon dioxide over the first layer within the opening, material from the first and second layers within the opening being comprised by the shallow trench isolation region and the forming of the second layer of silicon dioxide comprising:
• forming a high density plasma proximate the substrate;
• flowing gases into the plasma, at least some of the gases forming silicon dioxide;
• maintaining the substrate at a temperature of at least about 500° C.;
• and
• while maintaining the substrate at said temperature, depositing the silicon dioxide formed from the gases within the opening.