We analyze the properties of truly confined modes of a slot-photonic crystal slab on silicon-on-insulator structures. Recently, Galli et al [1] have demonstrated the enhancement of photoluminescence in slot-photonic crystal slabs, however, their structure supported only lossy modes. We designed and calculated the band structure and linear defect guided modes for slab confined structures. Two cladding configurations, which are strong candidates for fabrication, are investigated. The field enhancement in the confined mode of a slot-photonic crystal offers significant promise for new light emitting devices on silicon.