Fowler-Nordheim tunneling in mos capacitors with Si-implanted SiO2

The gate current density (J(G))-voltage (V-G) characteristics of MOS capacitors with 50 nm thick SiO2 and Various Si-implanted doses from 10(13) to 3 x 10(16) cm(-2) have been studied under inversion- and accumulation-conditions. The conduction mechanism is discussed by making use of Fowler-Nordheim (F-N) and Poole-Frenkel (P-F) plots of the J(G)-V-G characteristics with/without a cyclic stress test. The F-N plot for samples without cyclic stress has a linear region which implies the F-N current mechanism. The tunneling barrier height Phi(B) calculated from the slope of the F-N plots begins to decrease beyond a dose of 10(14) cm-2. The cyclic stress test of the Si-implanted samples gives saturated hysteresis J(G)-V-G curves, which depend on the implantation condition. Since the P-F plot has a linear region, the P-F current is dominant in the samples with a cyclic stress for \J(G)\ > 10(-7) A/cm(2). The direct tunneling electron/hole current between inversion/accumulation layers in p-Si substrate and traps in SiO2 may be responsible for a J(G) value under 10(-7) A/cm(2), owing to the fact that J(G) has a hysteresis characteristics and that no linear region exists in either F-N or P-F plot. (C) 1998 Elsevier Science Ltd. All rights reserved.