JPH0336761A - Semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a high frequency amplifying FET with low distortion by forming a first and a second FET's, with different gate-source voltage (VGS) dependency of mutual conductance (gm), on a semiconductor substrate, and connecting gates, sources, and drains of both FET's respectively to make the mutual conductance flat near the operating point. CONSTITUTION:Impurity ions I are injected into a semi-insulating compound semiconductor substrate 203 by using a resist 204 as a mask. Then, injecting n<+> into the source and the drain regions are evaporating source, drain, gate metals to form a source electrode 206, a drain electrode 205, and a gate electrode 207 and respective electrodes are connected. Active layers 201 and 202 are formed by using different ion injecting conditions to obtain a gm-VGS characteristic 105 of an FET 101 and a gm-VGS characteristic 106 of an FET 102.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a FET (field effect transistor) for high frequency amplification with low distortion, but it is still a conventional technology. There is a strong desire for low distortion in FETs for high frequency amplification. (mutual conductance) characteristics as shown in Figure 3, lot is FET,
103 is drain 1 desire 1゜4 is gate bias 1 faction 2
00 is a characteristic curve showing the dependence of gm on the gate-source voltage (Vo capacity) & When multiple human input signals are applied to the gate of the FET, the distortion component 1 that appears in the output signal depends on the nonlinearity of the FET. . In other words, if the source and drain current (Ios) flowing through the FET is expressed by Van, 1os-a@+a+Vo*+atVas''+asVa
The second-order distortion is determined by a2, and the third-order distortion is determined by a3. −・・・−〇, a+≠0
When , the distortion component becomes zero. Therefore, as the differential term with respect to Vas of the gm-Vo* curve near the operating point is close to zero, the distortion component becomes small.

Problem to be Solved by the InventionHowever, there is a disadvantage in that although it is extremely difficult to bring the differential term with respect to Vat of the gm-Vat curve near the operating point of +1FET close to zero using the conventional method described above, this i;LF
The distribution of impurities in the depth direction due to the ion implantation method during ET formation has a distribution close to a Gaussian distribution.
The present invention solves the above conventional problems, and aims to provide a FET for high frequency amplification with low distortion. For F E
An eleventh second FET having different gm dependence on Ves is formed on the Ti&semiconductor substrate, and both of the FETs are
This configuration creates a region where the differential term with respect to Vat in the gm-Vow curve is close to zero. By selecting the operating point as the operating point, a high-frequency amplification FET with low distortion can be manufactured. In FIG. 1(a), 101 and 102 are FETs, 103 is a drain heavy state, 104 is a gate bias type temperature control device, and in FIG. 1(b), 105 is an FET. E T 101 gm-Vas special i
106 is the gm-Vow characteristic of FET 102, 10
7f;t, F E'r 101 and 102 gm-
As a whole, the circuit configured as shown in Figure 1(a) is the sum of the Vest characteristics. If set to around 5-OV, it is possible to realize a high frequency amplifier with extremely low distortion due to the fact that the gm is flat. Figure 2(a) shows the first FE.
Active layer 201α of T. FIG. 2(b) shows a method of forming the active layer 202 of the second FET.
4 as a mask, impurity ions I are implanted into the semi-insulating compound semiconductor substrate 203, and n+ implantation is performed into the resistor and drain regions. Source, drain, and gate metals are evaporated, and the source electrode 20 large train is formed. Electrode 2
Form the gate electrode 207. Connect each electrode as shown in Figure 2(c).The active layers 201 and 202 are implanted under different ion implantation conditions to obtain the characteristics corresponding to Figure 105 and 106, respectively. It is formed using

Effects of the Invention As described above, in accordance with the present invention, an excellent semiconductor device for high frequency amplification that performs low distortion amplification can be realized by connecting a plurality of FETs having different Vas dependencies of gm in parallel. too

[Brief explanation of drawings]

FIG. 1(a) shows the circuit of the semiconductor device according to the first embodiment of the present invention. FIG. 1(b) shows the gm-Va* characteristics of the semiconductor device according to the first embodiment of the present invention. Figure 3 shows the circuit diagram of a conventional semiconductor device and GM-I
/am characteristic diagram

Claims (2)

[Claims] (1) A mutual conductance gate on a semiconductor substrate.
It is characterized by forming first and second field effect transistors having different source-to-source voltage dependencies, and connecting the gates, sources, and drains of both transistors, respectively, and flattening the mutual conductance near the operating point. Semiconductor equipment. (2) First FET and second FE in the same semiconductor substrate
2. The semiconductor device according to claim 1, wherein the active regions of T are formed using different ion implantation conditions.