Moderately doped NMOS (M-LDD)-hot electron and current drive optimization

Short-channel NMOS transistors with moderately doped drain (10¹⁴ cm^-2), and variable sidewall oxide spacer thickness were fabricated and studied. The sensitivities of hot carrier degradation, current drive capability, and other device parameters to the sidewall spacer thickness were measured and evaluated. The results clearly indicate that a moderately doped drain (M-LDD) provides a stable and well-optimized device, compared to a conventional LDD transistor with substantially lower implant dose. A simple model, explaining the observations, is proposed and discussed