JPH054521U - Insulated gate type field effect transistor - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the high frequency characteristics of an insulated gate field effect transistor. [Structure] A plurality of gate electrodes (11) are connected to each other (12)
To form a comb-like shape, and the connecting portion (12) has an enlarged portion (1
6) is formed, and the extraction electrode (14) is brought into ohmic contact with substantially the entire surface of the connecting portion (12) including the enlarged portion (16).

Description

[Detailed description of the device]

[0001]

[Industrial applications]

  The present invention relates to a discrete high frequency insulated gate field effect transistor. To do.

[0002]

[Prior art]

  A conventional device of this type is shown in FIG. This device uses a gate oxide on a silicon substrate. A plurality of polysilicon gate electrodes (1) are formed in parallel through the film, By connecting one end of the gate electrode (1) with the connecting portion (2), the entire gate electrode (1) is The body has a comb-shaped pattern, and a contact hole (3) is formed at one end of the connecting part (2). And the Al extraction electrode (4) is ohmic through the contact hole (3). When contacted, the extraction electrode (4) extended over the insulating film and connected to the electrode pad (5). (For example, JP-A-61-214579).

[0003]   In the case of a dual gate type, two adjacent gate electrodes (1) form a pair and One unit transistor cell is formed.

[0004]

[Problems to be solved by the device]

  However, in the conventional insulated gate field effect transistor as shown in FIG. The output electrode (4) only contacts one end of the connecting portion (2) of the gate electrode (1) Therefore, the resistance of the polysilicon layer of the connecting portion (2) increases. That Therefore, the signal transmission to the unit transistor cells is not evenly performed, such as in the VHF band. In the high frequency band, there are drawbacks such as reduction of gain and deterioration of noise level.

[0005]

[Means for Solving the Problems]

  The present invention has been made in view of the above-mentioned drawbacks, and corresponds to a tooth portion of a comb tooth pattern. Extraction electrode (14) at all the connecting portions between the gate electrode (11) and the connecting portion (12) A contact hole (13) to make ohmic contact with By providing the enlarged portion (16) in the connecting portion (12) of the electrode (11), a high frequency characteristic can be obtained. Provided is an insulated gate field effect transistor having improved characteristics.

[0006]

[Action]

  According to the present invention, the extraction electrode (1) having a low resistance is provided over substantially the entire length of the connecting part (12). By making 4) ohmic contact, the gate electrodes (11) of each cell are evenly distributed. Can signal. Further, by enlarging a part of the connecting portion (12), the connecting portion ( The contact resistance between 12) and the extraction electrode (14) can be significantly reduced.

[0007]

【Example】

  An embodiment of the present invention will be described below in detail with reference to the drawings.

[0008]   FIG. 1 is a plan view showing a pattern of a gate electrode (11) of the device of the present invention, and FIG. FIG. 3 is a plan view showing one cell, and FIG. 3 is a sectional view thereof.

[0009]   In FIG. 1, (11) is polysilicon extending on the gate oxide film on the substrate surface. The gate electrode (12) is formed of the same polysilicon layer as the gate electrode (11) A connecting portion of the gate electrode (11), and (13) an insulating film covering the gate electrode (11) The contact hole (14) is opened through the contact hole (13). Al take-out electrode in ohmic contact with the lower connecting part (12), (15) take-out Bonding pad for external connection continuous from the electrode (14), and (16) connecting part It is an enlarged portion obtained by enlarging a part of (12).

[0010]   The gate electrode (11) extending in parallel has a connecting portion extending so as to be orthogonal thereto. One end is commonly connected by (12), and a comb-shaped pattern is formed as a whole. To do. The contact hole (13) is provided with a connecting portion (12) and an expansion of the connecting portion (12). It is formed with the maximum area so as to follow the shape of the large part (16). This element is dual In the case of a gate type insulated gate field effect transistor, the enlarged portion (16) Is provided for the electrode for the first gate, and the two gate electrodes (11) form a pair. That constitutes one cell.

[0011]   FIG. 2 shows one cell of a dual gate type device. The drain electrode is in the center A contact hole (17) for making a close contact is formed, and a second gate is formed around the contact hole. The gate electrode (18) so as to surround the first gate electrode (1). 1) extends in a comb shape. The contact hole (19) for the source electrode is the first gate. Located outside the electrode (11).

FIG. 3 is a sectional view thereof. P-type silicon substrate (20) a source region (21) and the drain region N-type on the surface of the (22), and an intermediate region (23) is formed, the source electrode through a P ⁺ -type contact region (24) ( A back gate bias is applied to the substrate (20) by means of 25), and first and second gate electrodes (11) and (18) are formed on the gate insulating film (26), and the first and second gate electrodes (11) are formed. (18) is covered with a CVD oxide film (27), and a drain electrode (28) is arranged on the surface of the drain region (22). When this element is used in a VHF band tuner circuit, the source is grounded, a signal input is applied to the first gate electrode (11), and a signal is applied to the second gate electrode (18) grounded at high frequency. By adjusting the bias voltage, the drain current is changed and the power gain is adjusted.

[0013]   In the device of the present invention described above, the low-resistance take-out electrode (14) is used for the gate of each cell. Ohmic contact is made with all the connecting portions between the electrode (11) and the connecting portion (12). Therefore, the gate electrode (11) of each cell can be operated uniformly. further, By forming the enlarged portion (16) in the connecting portion (12), the extraction electrode (14) and The contact resistance with the connecting portion (12) can be significantly reduced. Therefore, high frequency resistance Since the amount can be reduced, the high frequency gain can be improved and the NF can be improved.

[0014]

[Effect of device]

  As described above, according to the present invention, the signal can be uniformly transmitted to each cell. It has an advantage that a pattern layout with less loss can be realized. In addition, contact resistance It also has the advantage of improving the high frequency gain and reducing the noise level. To do.

[Brief description of drawings]

FIG. 1 is a plan view for explaining the present invention.

FIG. 2 is a plan view showing one cell.

FIG. 3 is a cross-sectional view showing a cell portion.

FIG. 4 is a plan view illustrating a conventional example.

Claims (2)

[Scope of utility model registration request] 1. An insulating film formed on a semiconductor substrate, a plurality of gate electrodes arranged in parallel on the insulating film, and one end of the gate electrode extending perpendicularly to the gate electrode. Insulated gate type including a connecting portion of the gate electrode to be connected, an insulating film covering the gate electrode, and an extraction electrode in ohmic contact with the connecting portion of the gate electrode through a contact hole formed in the insulating film. In the field effect transistor, the extraction electrode is in contact with substantially the entire length of the connecting portion of the gate electrode, and an enlarged portion is provided in the connecting portion of the gate electrode. 2. The insulated gate field effect transistor, wherein the gate electrode is a first gate of a dual gate field effect transistor.