Methods of forming microelectronic devices including stair step structures

A method of forming a microelectronic device, comprising:

• forming a multi-deck structure comprising:
• a lower deck comprising tiers respectively comprising first material and second material vertically adjacent to the first material;
• an upper deck vertically overlying the lower deck and comprising additional tiers respectively comprising the first material and the second material vertically adjacent to the first material;
• and
• an interdeck dielectric material vertically between the first deck and the second deck;
• forming a staircase structure within the multi-deck structure, the staircase structure having steps defined by horizonal ends of the tiers of the lower deck, the interdeck dielectric material, and the additional tiers of the upper deck;
• forming doped dielectric oxide material within a trench having boundaries defined by the steps of the staircase structure, the doped dielectric oxide material comprising one or more of boron, phosphorus, fluorine, and carbon;
• and
• forming substantially undoped dielectric oxide material within the trench and over the doped dielectric oxide material.

A method of forming a microelectronic device, comprising:

• forming a multi-deck structure comprising:
• a first deck comprising a vertically alternating sequence of first material and second material arranged in tiers;
• an interdeck dielectric material over the first deck;
• a second deck over the interdeck dielectric material and comprising an additional vertically alternating sequence of the first material and the second material arranged in additional tiers;
• and
• sacrificial material over the second deck;
• forming stadium structures within the multi-deck structure, the stadium structures respectively including opposing staircase structures individually having steps defined by edges of the of the first deck, the interdeck dielectric material, and the second deck;
• forming substantially undoped dielectric material within trenches respectively having boundaries defined by the opposing staircase structures of one of the stadium structures;
• forming doped dielectric material within a trench and on the substantially undoped dielectric oxide material, the doped dielectric material comprising one or more dopants selected from boron, phosphorus, fluorine, and carbon;
• and
• substantially removing portions of the sacrificial material, the substantially undoped dielectric material, and the doped dielectric material outside of horizontal areas of the stadium structures.