Waveform displaying method and waveform analyzing apparatus
AssigneeNEC Corporation
InventorNorio Goto
Life of this patent
Estimating the term…
Abstract
Temperature-dependent waveforms, variable with time, of the output characteristics such as current, capacitance, threshold voltage, and the like of a semiconductor device are measured and analyzed in a short period of time for accurately and quickly identifying deep levels in the semiconductor device. When a step voltage is applied to a terminal of the semiconductor device, the output characteristics thereof respond with a waveform I. After the elapse of a time t from the application of the step voltage, the value of t.multidot.(dI/dt) is measured and stored at a plurality of temperatures T. The recorded values are three-dimensionally displayed in a space coordinate system having an x-axis representing 1/T, a y-axis representing log(tT.sup.2), and a z-axis representing t.multidot.(dI/dt).
Claims4
A method of measuring and displaying a waveform of a response, variable with time, of an output characteristic from a terminal of a semiconductor device in response to a step voltage applied to a terminal thereof, comprising the steps of:
- measuring and recording in a recording device an outcome of a multiplication operation of a time t and a derivative, with respect to time, of the waveform of a response of the output characteristic after the elapse of time t from the application of the step voltage at each of a plurality of temperatures T;
- and
- displaying on a display means the recorded outcome in a form of a three-dimensional representation in a space coordinate system having a first axis representing the reciprocals of the temperatures T, a second axis representing the logarithms of the products of the squares of the temperatures T and the time t, and a third axis representing said outcome of a multiplication operation of the derivative and the time t.
A method of displaying a waveform of a response, variable with time, of a current from a terminal of a diode or a transistor mounted on a substrate in response to a step voltage applied to a terminal thereof, comprising the steps of:
- measuring and recording the product of a time t and a derivative, with respect to time, of the waveform of a response of the current after the elapse of time t from the application of the step voltage at each of a plurality of temperatures T;
- and
- displaying the recorded products three-dimensionally in a space coordinate system having a first axis representing the reciprocals of the temperatures T, a second axis representing the logarithms of the products of the squares of the temperatures T and the time t, and a third axis representing the product of the derivatives and the time t.
A method of displaying a waveform of a response, variable with time, of a capacitance between two terminals of a diode or a transistor mounted on a substrate in response to a step voltage applied to a terminal thereof, comprising the steps of:
- measuring and recording the product of a time t and a derivative, with respect to time, of the waveform of a response of the capacitance after the elapse of time t from the application of the step voltage at each of a plurality of temperatures T;
- and
- displaying the recorded products three-dimensionally in a space coordinate system having a first axis representing the reciprocals of the temperatures T, a second axis representing the logarithms of the products of the squares of the temperatures T and the time t, and a third axis representing the product of the derivatives and the time t.
A method of displaying a waveform of a response, variable with time, of a voltage at a terminal of a diode or a transistor mounted on a substrate, which voltage is to be applied to keep a current from a terminal thereof at a certain level, in response to a step voltage applied to a terminal thereof, comprising the steps of:
- measuring and recording the product of a time t and a derivative, with respect to time, of the waveform of a response of the voltage after the elapse of time t from the application of the step voltage at each of a plurality of temperatures T;
- and
- displaying the recorded products three-dimensionally in a space coordinate system having a first axis representing the reciprocals of the temperatures T, a second axis representing the logarithms of the products of the squares of the temperatures T and the time t, and a third axis representing the product of the derivatives and the time t.
Dependencies are inferred from the claim text.