Semiconductor devices comprising carbon-doped silicon nitride and related methods

A semiconductor device comprising:

• a staircase structure comprising tiers of alternating dielectric levels and conductive levels;
• an etch stop material comprising carbon-doped silicon nitride over the tiers of the staircase structure, the etch stop material comprising a non-stoichiometric amount of carbon;
• and
• contacts extending into the conductive levels of the tiers.

A semiconductor device comprising:

• a staircase structure comprising tiers of alternating dielectric levels and conductive levels;
• an etch stop material comprising hafnium oxide at least partially over the tiers of the staircase structure;
• contacts extending through the etch stop material, the dielectric levels, and into but not through the conductive levels of the tiers, each conductive level in electrical contact with a respective contact;
• a channel material extending through a portion of the tiers of the dielectric levels and conductive levels;
• and
• memory cells along a length of the channel material.