Integration of high voltage charge-pumps in a submicron standard CMOS process for programming analog floating-gate circuits

This paper presents integration of high voltage charge-pumps for programming analog floating-gate (FG) circuits in a standard 0.5 μm CMOS N-well double poly process. In this research two different Dickson charge-pumps are integrated for the control of electron tunneling and hot-electron injection in a floating-gate element. A six stage design implemented with Schottky rectifiers is used to modulate tunneling and a three stage design using high voltage transistors is used to modulate injection. Controlling the frequency of the Schottky charge-pump is an on-chip clock. The on-chip clock, a 7 stage ring oscillator was designed to operate to approximately 10 MHz for controlling the Schottky charge-pump. Experimental results of hot-electron injection, clock performance and electron tunneling are presented.