Evaluation method of insulating film and measurement circuit thereof
View Patent ↗Provided is a method of evaluating dielectric breakdown by applying a current to an insulating film, in which measurement for a forward direction current and measurement for a backward direction current are performed in a short period of time. For this purpose two MOS diodes in which an electrode of one MOS diode and a base of another MOS diode are short-circuited respectively are prepared to form a circuit to which the current is applied, providing current flow in one insulating film reverse to current flow in another insulating film, which enables the application of both the forward direction current and the backward direction current.
1. An insulating film evaluation method, employing a measurement circuit which comprises:
a first MOS diode including:
a first diffusion layer formed on a semiconductor substrate of one conductivity type and having an opposite conductivity type, a first insulating film formed on the first diffusion layer, and a first electrode formed on the first insulating film;
a second MOS diode including:
a second diffusion layer formed close to the first diffusion layer, a second insulating film formed on the second diffusion layer, and a second electrode formed on the second insulating film;
a first terminal connected to the first electrode and the second diffusion layer;
a second terminal connected to the second electrode and the first diffusion layer;
a current source interposed between the first terminal and the second terminal; and
a voltmeter placed in parallel to the current source,
the insulating film evaluation method comprising:
applying an electric current flow in one direction between the first terminal and the second terminal to measure a change in voltage between the terminals.
2. A measurement circuit for an insulating film, comprising:
a first MOS diode including: a first diffusion layer formed on a semiconductor substrate of one conductivity type and having an opposite conductivity type, a first insulating film formed on the first diffusion layer, and a first electrode formed on the first insulating film;
a second MOS diode including: a second diffusion layer formed close to the first diffusion layer, a second insulating film formed on the second diffusion layer, and a second electrode formed on the second insulating film;
a first terminal connected to the first electrode and the second diffusion layer;
a second terminal connected to the second electrode and the first diffusion layer;
a current source interposed between the first terminal and the second terminal; and
a voltmeter placed in parallel to the current source.
3. An insulating film evaluation method, employing a measurement circuit which comprises:
a first MOS diode including:
a first diffusion layer formed on a semiconductor substrate of one conductivity type and having an opposite conductivity type, a first insulating film formed on the first diffusion layer, and a first electrode formed on the first insulating film;
a second MOS diode including:
a second diffusion layer formed close to the first diffusion layer, a second insulating film formed on the second diffusion layer, and a second electrode formed on the second insulating film;
first means to electrically connect the first electrode and the second diffusion layer;
second means to electrically connect the second electrode and the first diffusion layer;
a current source interposed between the first means and the second means to apply current therebetween; and
a voltmeter placed in parallel to the current source,
the insulating film evaluation method comprising:
applying an electric current flow in one direction between the first terminal and the second terminal to measure a change in voltage between the terminals.
4. A measurement circuit for an insulating film, comprising:
a first MOS diode including:
a first diffusion layer formed on a semiconductor substrate of one conductivity type and having an opposite conductivity type, a first insulating film formed on the first diffusion layer, and a first electrode formed on the first insulating film;
a second MOS diode including:
a second diffusion layer formed close to the first diffusion layer, a second insulating film formed on the second diffusion layer, and a second electrode formed on the second insulating film;
first means to electrically connect the first electrode and the second diffusion layer;
second means to electrically connect the second electrode and the first diffusion layer;
a current source interposed between the first means and the second means to apply current therebetween; and
a voltmeter placed in parallel to the current source.