MOS field-effect transistor
View Patent ↗A high-reliable depletion-type MOS field-effect transistor as a process monitor is provided. A diode formed in polycrystalline silicon and a diode formed in a semiconductor substrate form a bi-directional diode. The bi-directional diode connects a gate electrode with the semiconductor substrate in the depletion-type MOS field-effect transistor through metal wirings.
1. A depletion-type MOS field effect transistor, comprising:
a P-type semiconductor substrate;
N-type high-concentration source/drain regions disposed on the semiconductor substrate;
a gate insulating film disposed on the semiconductor substrate;
a gate electrode comprised of a first polycrystalline silicon and disposed on the gate insulating film;
a PN junction diode disposed in a second polycrystalline silicon film which is disposed over the semiconductor substrate;
an intermediate insulating film disposed on the gate electrode, and on the second polycrystalline silicon film;
a first metal wiring connecting the gate electrode with an N-type region of the PN junction diode;
a second metal wiring connecting a P-type region of the junction diode with a high-concentration P-type region disposed on the semiconductor substrate; and
a protective film comprised of a nitride film and disposed on the metal wirings.
2. A depletion-type MOS field effect transistor according to claim 1 , wherein an opening of the protective film comprised of the nitride film is disposed on the second polycrystalline silicon film.
3. A depletion-type MOS field effect transistor, comprising:
a P-type semiconductor substrate;
N-type high-concentration source/drain regions disposed on the semiconductor substrate;
a gate insulating film disposed on the semiconductor substrate;
a gate electrode comprised of a first polycrystalline silicon and disposed on the gate insulating film;
a bi-directional diode disposed in a second polycrystalline silicon film which is disposed over the semiconductor substrate, the bi-directional diode being constituted by two P-type regions and an N-type region sandwiched therebetween;
an intermediate insulating film disposed on the gate electrode, and on the second polycrystalline silicon film;
a first metal wiring connecting the gate electrode with one of the P-type regions in the second polycrystalline silicon;
a second metal wiring connecting the other P-type region in the second polycrystalline silicon with a high-concentration P-type region disposed on the semiconductor substrate; and
a protective film comprised of a nitride film and disposed on the metal wirings.
4. A depletion-type MOS field effect transistor according to claim 3 , wherein an opening of the protective film comprised of the nitride film is disposed on the second polycrystalline silicon film.
5. A depletion-type MOS field effect transistor, comprising:
a P-type semiconductor substrate;
N-type high-concentration source/drain regions disposed on the semiconductor substrate;
a gate insulating film disposed on the semiconductor substrate;
a gate electrode comprised of a first polycrystalline silicon and disposed on the gate insulating film;
a bi-directional diode disposed in a second polycrystalline silicon film which is disposed over the semiconductor substrate, the bi-directional diode being constituted by two N-type regions and a P-type region sandwiched therebetween;
an intermediate insulating film disposed on the gate electrode, and on the second polycrystalline silicon film;
a first metal wiring connecting the gate electrode with one of the N-type regions in the second polycrystalline silicon;
a second metal wiring connecting the other N-type region in the second polycrystalline silicon with a high-concentration P-type region disposed on the semiconductor substrate; and
a protective film comprised of a nitride film and disposed on the metal wirings.
6. A depletion-type MOS field effect transistor according to claim 5 , wherein an opening of the protective film comprised of the nitride film is disposed on the second polycrystalline silicon film.
7. A depletion-type MOS field effect transistor, comprising:
a P-type semiconductor substrate;
N-type high-concentration source/drain regions disposed on the semiconductor substrate;
a gate insulating film disposed on the semiconductor substrate;
a gate electrode comprised of a first polycrystalline silicon and disposed on the gate insulating film;
a bi-directional diode disposed in a second polycrystalline silicon film which is disposed over the semiconductor substrate, the bi-directional diode being constituted by an odd number, which is not less than three, of P-type regions and an even number of N-type regions sandwiched among the P-type regions;
an intermediate insulating film disposed on the gate electrode, and on the second polycrystalline silicon film;
a first metal wiring connecting the gate electrode with the P-type region at one end of the bi-directional diode in the polycrystalline silicon;
a second metal wiring connecting the P-type region at the other end of the bi-directional diode in the polycrystalline silicon with a high-concentration P-type region disposed on the semiconductor substrate; and
a protective film comprised of a nitride film and disposed on the metal wirings.
8. A depletion-type MOS field effect transistor according to claim 7 , wherein an opening of the protective film comprised of the nitride film is disposed on the second polycrystalline silicon film.
9. A depletion-type MOS field effect transistor, comprising:
a P-type semiconductor substrate;
N-type high concentration source/drain regions disposed on the semiconductor substrate;
a gate insulating film disposed on the semiconductor substrate;
a gate electrode comprised of a first polycrystalline silicon and disposed on the gate insulating film;
a bi-directional diode disposed in a second polycrystalline silicon film which is disposed over the semiconductor substrate, the bi-directional diode being constituted by an odd number, which is not less than three, of N-type regions and an even number of P-type regions sandwiched among the N-type regions;
an intermediate insulating film disposed on the gate electrode, and on the second polycrystalline silicon film;
a first metal wiring connecting the gate electrode with the N-type region at one end of the bi-directional diode in the polycrystalline silicon;
a second metal wiring connecting the N-type region at the other end of the bi-directional diode in the polycrystalline silicon with a high-concentration P-type region disposed on the semiconductor substrate; and
a protective film comprised of a nitride film and disposed on the metal wirings.
10. A depletion-type MOS field effect transistor according to claim 9 , wherein an opening of the protective film comprised of the nitride film is disposed on the second polycrystalline silicon film.
11. A depletion-type MOS field effect transistor, comprising:
a P-type semiconductor substrate;
N-type high-concentration source/drain regions disposed on the semiconductor substrate;
a gate insulating film disposed on the semiconductor substrate;
a gate electrode comprised of a first polycrystalline silicon and disposed on the gate insulating film;
a PN junction diode disposed in a second polycrystalline silicon film which is disposed over the semiconductor substrate;
an intermediate insulating film disposed on the gate electrode, and on the second polycrystalline silicon film;
a first metal wiring connecting the gate electrode with a P-type region of the PN junction diode
a second metal wiring connecting an N-type region of the junction diode with a high-concentration N-type region disposed on the semiconductor substrate and
a protective film comprised of a nitride film and disposed on the metal wirings.
12. A depletion-type MOS field effect transistor according to claim 11 , wherein an opening of the protective film comprised of the nitride film is disposed on the second polycrystalline silicon film.