Programming floating-gate circuits with UV-activated conductances

Abstract

A programming technique for controlling the floating gates (FGs) in ultra-low-voltage (ULV) floating-gate circuits is presented. Simple ULV FG current-scaling and level-shifting circuits are discussed. The current scaling and level shifting are accomplished using only minimum sized transistors and floating capacitors. Floating-gate current multiplier and divider circuits are described. Measured results are provided.

Differential Hot Electron Injection in an Adaptive Floating Gate Comparator

“…In contrast, differential-mode adaptation uses the more readily integrated technique of hot electron injection for updating the state variables. FowlerNordheim tunneling is used only to fix the initial values and common mode voltages of state variables; other mechanisms such as UV illumination or capacitive coupling of an auxiliary electrode can also be used for this purpose [8,9].…”

Design of a Single-Chip pH Sensor Using a Conventional 0.6-<tex>$muhbox m$</tex>CMOS Process

“…The UV light excites the electrons on the gate to such an extent that they can overcome the oxide energy barrier and discharge the gate. UV programming of floating-gate transistors has been demonstrated using polysilicon-polysilicon capacitors in another CMOS process from the same foundry, with a dielectric oxide that is 1.6 times as thick as the gate oxide being used here [14]. Accordingly, the ISFET was exposed to UV light using an EPROM eraser to investigate the effect that this had on the threshold voltage.…”

Proposal for a Bidirectional Gate Using Pseudo Floating-Gate

“…Within each of the disciplines there are different techniques to obtain the desired voltage levels. For discipline (1) the well-known are Fowler-Nordheim tunnelling [1], hot-carrier injection [1] and the UV activated conductance [2]. It is worth emphasising that discipline (1) has an disadvantage due to time-consuming initialisation of the floating-gates and leakage.…”