Analog-to-digital converter made with focused ion beam technology

Claim 1

An analog-to-digital (A/D) converter comprising: a plurality of comparators having monotonically increasing transition levels, each comparator including at least one field effect transistor having drain, source and gate regions; the gate region overlying a channel in a semiconductor substrate; input means for providing an analog input signal simultaneously to each comparator; the transistors in each comparator each having a different threshold level due to different concentrations of impurities implanted in the channel regions thereof by focused ion beam implantation techniques thereby defining said transition levels for each of the comparators; and decoder means coupled to outputs of each of the comparators for generating a digital output signal as a function of the comparator outputs; each comparator including a least one complementary metal oxide (CMOS) inverter employing an N-channel and P-channel transistor; each comparator comprising a pair of cross coupled inverters adapted to receive differential analog input signals.