Effect of some technological parameters on Fowler-Nordheim injection through tunnel oxides for non-volatile memories

In this work the effects of various technological parameters on Fowler-Nord heim injection through thin (around 7.2 nm) silicon dioxide films in metal- oxide-semiconductor capacitors have been studied. Attention has been paid t o the effect of gate geometry (round or strip gate) and area, substrate dop ing type (boron or phosphorus one), polycrystalline silicon gate structure (simple polysilicon or polysilicon-oxide-nitride-oxide-polysilicon structur e) and tunnel oxide type (standard or nitrided silicon dioxide). The effect of all these parameters on Fowler-Nordheim tunneling injection and on the potential barrier height at both oxide injecting interfaces are usually neg lected in literature and moreover the tunnel coefficients obtained from a s imple capacitor are used in the simulation of programmable operations of el ectrically erasable programmable read only memories. Quasi-static capacitan ce (voltage) and current (voltage) measurements have been performed and the latter have been simulated by using a constant effective barrier height at the injecting interface. We have found that Fowler-Nordheim tunneling para meters and potential barrier height at both oxide injecting interfaces are affected by the substrate doping type, oxide type, gate geometry and gate s tructure but they are not affected by the gate area. Moreover in all struct ures, a difference between the barrier heights at the two injecting interfa ces has been observed. The variation induced by the studied technological p arameters on the potential barrier height are comparable to the variation i nduced by considering a constant (classical theory) or electrical field dep endent (quantum theory) barrier height as reported in literature. (C) 2001 Elsevier Science B.V, All rights reserved.