MOSFET with a thin gate insulating film

• US 5,990,516 A
• Filed: 09/13/1995
• Issued: 11/23/1999
• Est. Priority Date: 09/13/1994
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Nakamura, Shinichi, Ono, Mizuki, Ohguro, Tatsuya, Momose, Hisayo, Iwai, Hiroshi, Yoshitomi, Takashi, Saito, Masanobu
• Primary Examiner(s): Hardy, David B.
• Application Number:
  US08/527,562
• Time in Patent Office: 1,532 Days
• Field of Search: 257/321, 257/260, 257/327, 257/356
• US Class Current: 257/327
• CPC Class Codes: H01L 21/2255 the applied layer comprising oxides only, e.g. P2O5, PSG, H3BO3, doped oxides
• CPC Class Codes: H01L 21/2256 through the applied layer
• CPC Class Codes: H01L 21/28211 in a gaseous ambient using an oxygen or a water vapour, e.g. RTO, possibly through a layer H01L21/28194 and H01L21/28202 take precedence
• CPC Class Codes: H01L 27/0629 in combination with diodes, or resistors, or capacitors
• CPC Class Codes: H01L 27/088 the components being field-effect transistors with insulated gate
• CPC Class Codes: H01L 29/42364 characterised by the insulating layer, e.g. thickness or uniformity H01L29/42324 and H01L29/4234 take precedence
• CPC Class Codes: H01L 29/42372 characterised by the conducting layer, e.g. the length, the sectional shape or the lay-out H01L29/42324 takes precedence
• CPC Class Codes: H01L 29/66575 where the source and drain or source and drain extensions are self-aligned to the sides of the gate H01L29/66606 takes precedence
• CPC Class Codes: H01L 29/78 with field effect produced by an insulated gate H01L29/7725, H01L29/775, H01L29/778 take precedence

Abstract

A semiconductor device comprises: a p-type semiconductor substrate (1); an insulating film (3); a gate electrode (2) formed on the substrate via the insulating film; and an n-type source/drain region (5) formed on both sides of a channel forming region (4) located under the gate electrode (2) formed on the substrate (1). In particular, the thickness (T_OX) of the insulating film (3) is determined to be less than 2.5 nm at conversion rate of silicon oxide film (silicon oxide equivalent thickness); a gate length (L_g) of the gate electrode (2) is determined to be equal to or less than 0.3 μm; and further a voltage applied to the gate electrode (2) and the drain region (6) is determined to be 1.5 V or less. Therefore, in the MOSFET having the tunneling gate oxide film (3), the reliability of the transistor under the hot carrier stress can be improved, and the gate leakage current can be reduced markedly, so that the transistor characteristics can be improved markedly.

Claims

1. A MOSFET, comprising:

a first-conductivity type semiconductor substrate;

an insulating film formed on said semiconductor substrate;

a gate electrode formed on said semiconductor substrate via said insulating film; and

a second-conductivity type source/drain region formed on both sides of a channel forming region located under said gate electrode formed on said semiconductor substrate via said insulating film; and

wherein a transconductance (gm) is as follows;

space="preserve" listing-type="equation">gm>

400 V.sub.DD +140 in nMOS

space="preserve" listing-type="equation">gm>

260 V.sub.DD +10 in pMOS

wherein a unit of V_DD is V and a unit of gm is mS/mm and gm value is that at room temperature.

2. The MOSFET of claim 1, wherein a voltage applied to said gate electrode and said drain region is 1.5 V or less.

3. The MOSFET of claim 2, wherein a voltage applied to said gate electrode and said drain region is 0.5 V or less.

4. The MOSFET of claim 1, wherein when the semiconductor device is in operation, direct-tunneling leakage current flows through said insulating film.

5. The MOSFET according to claim 1, wherein the transconductance (gm) is as follows:

space="preserve" listing-type="equation">gm>

530×

V.sub.DD +190 (in nMOS)

space="preserve" listing-type="equation">gm>

350×

V.sub.DD +13 (in pMOS).

6. The MOSFET according to claim 1, wherein the MOSFET as defined therein is included as a part of a semiconductor device.

7. A MOSFET comprising:

a first-conductivity type semiconductor substrate;

an insulating film formed on said semiconductor substrate;

a gate electrode formed on said semiconductor substrate via said insulating film; and

a second-conductivity type source/drain region formed on both sides of a channel forming region located under said gate electrode formed on said semiconductor substrate via said insulating film; and

wherein a current drive capability is as follows;

space="preserve" listing-type="equation">I.sub.d >

0.598 V.sub.DD -0.247 (in nMOS)

space="preserve" listing-type="equation">I.sub.d >

0.268 V.sub.DD -0.012 (in pMOS)

where a unit of V_DD is V and a unit of I_d is mA/μ

m.

8. The MOSFET according to claim 7, wherein the current drive capability is as follows:

space="preserve" listing-type="equation">I.sub.d >

0.80 V.sub.DD -0.33 (in nMOS)

space="preserve" listing-type="equation">I.sub.d >

0.36 V.sub.DD -0.14 (in pMOS).

9. The MOSFET according to claim 7, wherein the MOSFET as defined therein is included as a part of a semiconductor device.

10. A MOSFET comprising:

a first-conductivity type semiconductor substrate;

an insulating film formed on said semiconductor substrate;

a gate electrode formed on said semiconductor substrate via said insulating film; and

a second-conductivity type source/drain region formed on both sides of a channel forming region located under said gate electrode formed on said semiconductor substrate via said insulating film; and

wherein a transconductance (gm) is as follows;

space="preserve" listing-type="equation">gm>

400×

V.sub.DD +140 (in nMOS)

space="preserve" listing-type="equation">gm>

260×

V.sub.DD +10 (in pMOS)

where a unit of V_DD is V and a unit of gm is mS/mm and gm value is that at room temperature,

and wherein a current drive capability is as follows;

space="preserve" listing-type="equation">I.sub.d >

0.598 V.sub.DD -0.247 (in nMOS)

space="preserve" listing-type="equation">I.sub.d >

0.268 V.sub.DD -0.102 (in pMOS)

wherein a unit of V_DD is V and a unit of I_d is mA/μ

m.

11. The MOSFET according to claim 10, wherein a voltage applied to said gate electrode and said drain region is 1.5V or less.

12. The MOSFET according to claim 11, wherein a voltage applied to said gate electrode and said drain region is 0.5 V or less.

13. The MOSFET according to claim 10, wherein when the semiconductor device is in operation, direct-tunneling leakage current flows through said insulating film.

14. The MOSFET according to claim 10, wherein the MOSFET as defined therein is included as a part of a semiconductor device.