Double density non-volatile memory cells

Double density non-volatile memory cells having a trench structure are formed in a substrate, thereby facilitating miniaturization, improved planarization and low power programming and erasing. Each double density cell comprises two floating gates and a common control gate. Each pair of double density cells shares a common source region. Embodiments include forming first and second trenches in a substrate and depositing a tunnel dielectric layer in each trench. Polycrystalline silicon is then deposited filling each trench and a hole is etched forming two floating gate electrodes in each trench. An interpoly dielectric layer is then formed and a substantially T-shaped control gate electrode is deposited filling the hole between the floating gates and extending on the substrate.