A Test Structure for Statistical Evaluation of Characteristics Variability in a Very Large Number of MOSFETs

Abstract

We have proposed and developed a test structure for evaluating electrical characteristics variability of a large number of MOSFETs in very short time using very simple circuit structure.The electrical characteristics such as threshold voltage, subthreshold swings (S-factors, random telegraph signal noise, and so on, can be measured in over one million MOSFETs. This new test structure circuit and results measured by this circuit are very efficient in developing processes, process equipment and device structure which suppress variability.

Extraction of time constants ratio over nine orders of magnitude for understanding random telegraph noise in metal–oxide–semiconductor field-effect transistors

“…Figure 2 shows the circuit diagram of array test circuit for the evaluation of numerous MOSFETs. [19][20][21][22] In this test circuit, device under test (DUT) cells are consisted of measured and row switch transistors. And the DUT cells are placed in an arrayed pattern.…”

“…Using the test circuit, we can measure both the variation of I D -V GS characteristics and RTN characteristics from a large number of MOSFETs. [19][20][21][22][23] When a particular cell shows RTN, we can specify and observe it as dynamic fluctuation of V GS in the time scale. After identifying the MOSFETs showing RTN, the I D dependence of RTN characteristics in these MOSFETs are evaluated in detail by high-speed measurements with sampling period of 1 µs by fixing the shift registers addresses.…”

Parameter variation sensing and estimation in nanoscale fabrics

“…As a result, (17) can thus be decomposed into functions of the individual parameters, as shown in (18).…”

“…To derive the coefficients of polynomial functions in equation set (18), a device behavioral model encompassing parameter variations is built first. The xnwFET device structure is extensively characterized through variation-aware 3-D physics based simulations using Synopsys Sentaurus tools [14].…”

“…I-V curve measurement is a conventional approach to obtain characteristics for each transistor [17], [18]. However, in order to measure I-V curve, an analog voltage and current measurement equipment is required.…”