CMOS Signal processing circuits on Si (111) for neural activity image-recording with epitaxially grown micro-Si probes

This paper reports a signal processing circuits on Si (111) for the use in multi-point neural activity recording. The circuit for neural activity image-recording includes 64-site two-dimensional (2D) arrays, two 8-bit shift registers, and ripple carry counter. The problem when CMOS is formed on Si (111) is degradation of device performance caused by the higher density of interface states on Si (111) as compared with Si (100). Therefore, IC fabrication process was optimized for improving characteristic of MOSFET on Si (111). CMOS on Si (111) can be fabricated with required performance for recording system. The bandwidth of shift register on Si (111) is nearly equal to that on Si (100). The circuits on Si (111) are possible to be realized and available for neural activity image-recording.