KR101670650B1 - The manufacturing method of transistor for radiation measuring sensor - Google Patents

Abstract

The present invention relates to a method for manufacturing a transistor for a radiation measuring sensor which comprises the following steps: forming, on a substrate, a gate area where a gate electrode will be formed; determining the thickness of a gate insulation film formed in the gate area, adjusting the substrate concentration based on the determined thickness of the gate insulation film, and forming the gate insulation film in the gate area according to the determined thickness of the gate insulation film; forming a source and a drain according to the gate insulation film; and adjusting and forming a length and a width of the gate electrode according to the thickness of the gate insulation film. The present invention is to provide the method for manufacturing a transistor for a radiation measuring sensor which can enhance sensitivity of radiation measurement.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing a transistor for a radiation measurement sensor,

The present invention relates to a method of manufacturing a transistor for a radiation measurement sensor.

Radiation from nuclear facilities, space, and cancer treatment centers needs to be accurately detected. Such radiation should be converted into information that can be detected using the interaction with the radioactive material, since it can not be seen by eyes, by ears, or directly by the human senses.

Radiation measuring sensors that detect radiation are developed in various forms and methods according to the place of use, the intensity of radiation source, and the type of source, and they have unique characteristics.

Of these, semiconductor radiation measuring sensors are superior to other sensors in terms of small size, light weight and low power consumption. The germanium (Ge) radiation measuring sensor among semiconductor radiation measuring sensors requires a separate large cooling device, There is an advantage that unnecessary silicon (Si) series radiation measuring sensors can be manufactured in a very small size.

Among them, a radiation measuring sensor using a field-effect transistor (FET) detects the radiation dose using an electron-hole pair (EHP) formed inside the gate insulating film by the incident radiation In the measurement of the radiation exposure value, it is not necessary to construct the additional circuit for converting the instantaneous radiation value into the accumulated value, so that it can be manufactured in a small size and is specially manufactured and used as a radiation measurement sensor of an aerospace or satellite.

In recent years, there has been a demand for a high integration and a miniaturization of a radiation measurement sensor. In accordance with the demand for high integration and miniaturization of a radiation measurement sensor, The development of a transistor for a radiation measurement sensor capable of improving the performance of a radiation sensor is required.

It is an object of the present invention to provide a method of manufacturing a transistor for a radiation measurement sensor capable of improving the measurement sensitivity of radiation while maintaining the integration and miniaturization of the radiation measurement sensor.

According to an aspect of the present invention, there is provided a method of manufacturing a semiconductor device, including: forming a gate region on a substrate to be formed with a gate electrode; determining a thickness of the gate insulating film formed on the gate region; Forming a gate insulating film on the gate insulating film in accordance with the determined thickness of the gate insulating film; forming a source and a drain in accordance with a thickness of the gate insulating film; And adjusting the length and the width of the gate electrode.

As described above, in the method of manufacturing a transistor for a radiation measuring sensor according to an embodiment of the present invention, the gate insulating film is formed to have a thickness equal to or thicker than a predetermined thickness, thereby maintaining the integration and miniaturization of the radiation measuring sensor and improving the sensitivity .

In addition, the method of manufacturing a transistor for a radiation measurement sensor according to an embodiment of the present invention can improve the measurement sensitivity of radiation of a transistor for a radiation measurement sensor, thereby measuring not only space radiation but also medical and life radiation.

1A to 1G are views showing a manufacturing process of a transistor for a radiation measurement sensor according to an embodiment of the present invention.
2A is a graph showing a process time versus thickness of a gate insulating film formed by a dry oxidation method and a wet oxidation method.
FIG. 2B is a graph showing the process time versus the thickness of the gate insulating film according to the temperature difference when forming the gate insulating film. FIG.
3A, 3B, 3C, and 3 D are graphs showing changes in transfer characteristics of a transistor depending on a length L of a gate electrode, a thickness T of a gate insulating film, and a concentration difference of a substrate.
FIGS. 4A, 4B, 4C, and 4D are graphs showing changes in output characteristics of the transistor depending on the length L of the gate electrode, the thickness T of the gate insulating film, and the concentration difference of the substrate.
5A, 5B, 5C, and 5D are graphs showing changes in the transfer characteristics of the transistor depending on the length L of the gate electrode, the thickness T of the gate insulating film, and the concentration difference of the substrate.
6A, 6B, 6C, and 6D are graphs showing changes in the output characteristics of the transistor depending on the length L of the gate electrode, the thickness T of the gate insulating film, and the difference in the concentration of the substrate.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. However, this is merely an example and the present invention is not limited thereto.

In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

1A to 1G are views illustrating a process of manufacturing a transistor for a radiation measurement sensor according to an embodiment of the present invention.

1A, a transistor for a radiation measurement sensor according to an embodiment of the present invention may first form a gate region 110a on which a gate electrode 150 is to be formed.

Here, the substrate 110 may be formed of a silicon material. However, the present invention is not limited thereto.

At this time, an insulating layer 111 may be formed on the substrate 110. At this time, the insulating layer 111 may be formed by stacking a silicon oxide film and a poly-film. However, the present invention is not limited thereto.

The gate region 110a may be formed by etching the insulating layer 111 on the substrate 110 in the region where the gate electrode 150 is formed. At this time, the gate region 110a may be formed by forming a mask on the insulating layer 111, etching the region where the mask is opened, that is, the region where the mask is not formed, of the insulating layer 111 to form the gate region 110a .

Next, the thickness of the gate insulating layer 120 formed in the gate region 110a can be determined.

Subsequently, the substrate concentration Nsub of the substrate 110 may be adjusted according to the determined thickness of the gate insulating layer 120. [

1B, the gate insulating layer 120 may be formed on the gate region 110a in accordance with the determined thickness of the gate insulating layer 120. Referring to FIG.

Here, the gate insulating layer 120 may be formed through a high-temperature thermal oxidation process. In the thermal oxidation process, since the material element necessary for oxidizing silicon constituting the substrate 110 is oxygen (O ₂ ) (SiO ₂ ), that is, the gate insulating film 120, can be formed by combining the silicon oxide (O ₂ ) with silicon (Si).

Since the temperature and time that can be applied to the substrate 110 are limited according to the substrate concentration Nsub of the substrate 110, the substrate concentration Nsub may be adjusted according to the determined thickness of the gate insulating film 120 The thermal oxidation process for forming the gate insulating film 120 can be performed. At this time, the substrate concentration Nsub is the number of P, AS, and Sb atoms that are n-type impurities injected as impurities into the Si constituting the substrate 110 / cm ³ , thereby facilitating the formation of the gate insulating film 120 substrate concentration (Nsub) in order to make the 2.7E120cm ^-3 ~ 1.5E17cm ^- preferably from ^3.

Particularly, in the thermal oxidation process for forming the gate insulating layer 120, the gate insulating layer 120 may be formed on the substrate 110 through a wet oxidation method.

In contrast to the dry oxidation method in which oxygen (O ₂ ) is supplied at a high temperature, the wet oxidation method has a higher mass than that of oxygen (O ₂ ) in the oxidation process of combining oxygen (O ₂ ) and silicon The oxidation rate can be improved by supplying oxygen in the form of phosphorus (H ₂ O).

That is, in this embodiment, hydrogen gas and oxygen gas are mixed and reacted to supply oxygen in the form of water vapor (H ₂ O), thereby forming the gate insulating film 120. At this time, it is preferable that the gas pressure of the hydrogen gas and the oxygen gas is 30 mTorr to 250 mTorr so that the gate insulating film 120 can be formed stably and the oxidation rate can be improved.

2A is a graph showing a process time of a gate insulating film formed by a dry oxidation method and a wet oxidation method.

As can be seen from FIG. 2A, when the wet oxidation process at the same temperature forms the gate insulating film 120 having the same thickness as the dry oxidation process, the wet oxidation process can be performed in a shorter time. Also, it can be seen that the thickness increase efficiency of the gate insulating film 120 decreases with time in the dry oxidation process and the wet oxidation process as the thickness of the gate insulation film 120 becomes thicker.

Accordingly, in the method of manufacturing a transistor for a radiation measurement sensor according to an embodiment of the present invention, the gate insulating film 120 is formed through a wet oxidation method, thereby improving the thickness increase efficiency of the gate insulating film 120 with respect to time, Can be improved.

Meanwhile, the temperature during the thermal oxidation process for forming the gate insulating layer 120 is preferably 950 ° C to 1100 ° C.

If the temperature of the process thermal oxidation process is higher than 1100 DEG C during the formation of the gate insulating film 120, defects that may be generated in the transistor such as impurity distribution can be further generated as the temperature increases from 1100 DEG C, Is lower than 950 占 폚, there is a problem that the process time for forming the gate insulating film 120 is increased. Accordingly, the process temperature for forming the gate insulating film 120 is preferably 950 ° C to 1100 ° C.

FIG. 2B is a graph showing the thickness of the gate insulating film with respect to the process time for the temperature difference at the time of forming the gate insulating film.

As can be seen from FIG. 2B, when the temperature is 900 ° C. and 1000 ° C. in the course of the thermal oxidation process for forming the gate insulating film 120, the thickness variation of the gate insulating film 120 is 1000 ° C. , The thickness of the gate insulating film 120 formed at a temperature of 900 DEG C for one hour is 0.12 mu m. That is, it can be confirmed that the thickness of the gate insulating film 120 formed at a temperature of 1000 ° C during the thermal oxidation process for the same time is thicker than the thickness of the gate insulating film 120 formed at a temperature of 900 ° C.

Accordingly, the method for manufacturing a transistor for a radiation measurement sensor according to an embodiment of the present invention can form a gate insulating film 120 at a temperature of 950 ° C. to 1100 ° C., The gate insulating film 120 can be formed and the efficiency of increasing the thickness of the gate insulating film 120 with respect to time can be improved.

The gate insulating layer 120 may be formed by performing the thermal oxidation process using the mask used in forming the gate region 110a as it is.

At this time, the gate insulating layer 120 may be thicker than the insulating layer 111, and may be formed to have a thickness of 200 nm to 1000 nm to improve the measurement sensitivity of radiation.

That is, the gate insulating layer 120 is formed to have a thickness equal to or greater than a predetermined thickness according to a predetermined thickness of the gate insulating layer 120, thereby improving the measurement sensitivity of the radiation while maintaining the integration and miniaturization of the radiation measurement sensor . In addition, the measurement sensitivity of radiation can be improved to measure not only space radiation but also medical and life radiation.

Next, as shown in FIG. 1C, the source 131 and the drain 132 may be formed according to the thickness of the gate insulating layer 120.

The source 131 and the drain 132 may be formed by implanting ions into a partial region of the substrate 110. Depending on the thickness of the gate insulating layer 120, So as not to be injected.

Specifically, a mask in which a source region and a drain region are opened is formed on the insulating layer 111 and the gate insulating layer 120 to correspond to a portion where the source 131 is to be formed and a portion where the drain 132 is to be formed , The insulating layer 111 may be etched through the open source region and the drain region to expose the substrate 110. Thereafter, ions are injected into the exposed region of the substrate 110 to form the source 131 and the drain 132, and the mask can be removed.

1D, a dielectric layer 140 may be formed to cover the insulating layer 111, the gate insulating layer 120, the source 131, and the drain 132. Referring to FIG.

Next, as shown in FIG. 1E, a portion of the dielectric layer 140 may be removed so that the top surface of the gate insulating layer 120 is exposed.

At this time, a part of the dielectric layer 140 formed on the gate insulating layer 120 may be etched and removed through a mask having a portion corresponding to the gate insulating layer 120.

Also, as shown in FIG. 1F, a part of the dielectric layer 140 may be removed so that a part of the upper surface of the source 131 and the drain 132 is exposed.

At this time, a part of the dielectric layer 140 formed on the source 131 and the drain 132 is etched through the mask having the openings corresponding to the partial regions of the source 131 and the drain 132 formed on the dielectric layer 140 Can be removed.

Next, as shown in FIG. 1G, the length and width of the gate electrode 150 may be adjusted according to the thickness of the gate insulating layer 120.

At this time, the source 131 and the drain 132 may be formed with a connection unit 160 that can be connected to an external device.

The gate electrode 150 and the contact portion may be formed of a metal or a conductive polymer. Examples of the material include gold (Au), silver (Ag), aluminum (Al), nickel (Ni), indium tin oxide Examples thereof include polythiophene, polyaniline, polyacetylene, polypyrrole, polyphenylene vinylene, and polyethylenedioxythiophene (PEDOT) / polystyrenesulfonate (PSS). However, But is not limited thereto.

The length of the gate electrode 120 may be set to 0.5 or less to improve the measurement sensitivity of the radiation according to the thickness of the gate insulating layer 120. In addition, Mu] m to 15 mu m, and the width of the gate electrode 120 is preferably 800 mu m.

Hereinafter, the present invention will be described in more detail with reference to the transfer characteristics and output characteristics of a transistor for a radiation measurement sensor manufactured by the above-described manufacturing method according to the thickness of the gate insulating film, the length of the gate insulating film, and the substrate concentration. However, this is merely an example of the present invention, and the scope of the present invention should not be construed as being limited thereto.

< Example  1>

The concentration of the length (L) of the gate electrode 150 is 0.33㎛ (BL), 1㎛ (S0), 5㎛ (S1), 15㎛ (S2), and the substrate (11) 5E17cm ^{- 3} il , A transistor for a radiation measurement sensor having a thickness T of the gate insulating film 120 of 0.002 mu m was manufactured.

4A, 4B, 4C, and 4D are graphs showing changes in the transfer characteristics of the transistor depending on the length L of the gate electrode, the thickness T of the gate insulating film, and the concentration difference of the substrate. (L) of the gate electrode, the thickness (T) of the gate insulating film, and the concentration of the substrate.

The change in the threshold voltage and the saturation current for FIGS. 3A to 4D can be shown in Table 1 as follows.

BL S0 S1 S2 Threshold voltage (V) -0.35 -0.32 -0.31 -0.31 Saturation current (/ / 탆) -76.7 -27.9 -5.8 -1.9

As can be seen from FIGS. 3A to 4D and Table 1, as the length L of the gate electrode 150 increases, the saturation current value decreases linearly, but the threshold voltage does not change much. This result is due to the thin gate insulating film 120. This is because the thin gate insulating film 120 drives the gate electrode 150 at a small voltage, so that the longer the length L of the gate electrode 150, the greater the resistance effect can be.

< Example  2>

The concentration of the length (L) of the gate electrode 150 is 0.33㎛ (S3), 1㎛ (S4), 5㎛ (S5), 15㎛ (S6), and the substrate (11) 5E17cm ^{- 3} il , A transistor for a radiation measuring sensor having a thickness T of the gate insulating film 120 of 20 mu m was manufactured.

5A, 5B, 5C, and 5D are graphs showing changes in transfer characteristics of the transistor depending on the length L of the gate electrode, the thickness T of the gate insulating film, and the difference in the concentration of the substrate. FIGS. 6A, 6B, 6C, 6D is a graph showing changes in output characteristics of the transistor depending on the length L of the gate electrode, the thickness T of the gate insulating film, and the difference in the concentration of the substrate.

However, Figures 5a to 6d with a length (L) of the gate electrode 150 is 0.33 ~ 15㎛, the thickness (T) of the gate insulating film 120 is 0.02㎛, the concentration of the substrate (11) 5E17cm ^{-, 3} In the case of FIG.

The changes in threshold voltage and saturation current for FIGS. 5A to 6D are shown in Table 2 below.

S3 S4 S5 S6 Threshold voltage (V) -2.92 -2.79 -2.64 -2.56 Saturation current (/ / 탆) -62.8 -21.9 -4.2 -1.4

5A to 6D and Table 2, as the length L of the gate electrode 150 increases, the saturation current value decreases linearly. However, as the length L of the gate electrode 150 increases in the case of the threshold voltage, it can be confirmed that the gate electrode 150 moves in the positive direction.

That is, as can be seen from the comparison between the first embodiment and the second embodiment, when the length L of the gate electrode 150 is the same, the threshold voltage increases in the negative direction due to the increase in the thickness of the gate insulating film 120 It can be confirmed that the radiation measurement sensitivity of the transistor for a radiation measurement sensor is improved.

Reference throughout this specification to &quot; one embodiment &quot;, etc. of the principles of the invention, and the like, as well as various modifications of such expression, are intended to be within the spirit and scope of the appended claims, it means. Thus, the appearances of the phrase &quot; in one embodiment &quot; and any other variation disclosed throughout this specification are not necessarily all referring to the same embodiment.

Where a method is described herein as including a series of steps, the order of such steps presented herein is not necessarily the order in which such steps may be performed, any of the described steps may be omitted, Any other step that is not possible may be added to the method.

In addition, the singular forms herein include plural forms unless the context clearly dictates otherwise. Also, components, steps, operations, and elements referred to in the specification as &quot; comprises &quot; or &quot; comprising &quot; refer to the presence or addition of one or more other components, steps, operations, elements, and / or devices.

The present invention has been described with reference to the preferred embodiments. It is to be understood that all embodiments and conditional statements disclosed herein are intended to assist the reader in understanding the principles and concepts of the present invention to those skilled in the art, It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

110: substrate
120: Gate insulating film
131: source
132: drain
150: gate electrode
160: Connection

Claims (7)

Forming a gate region in the insulating layer of the substrate on which the gate electrode is to be formed;
Determining a thickness of the gate insulating film formed on the gate region, adjusting a substrate concentration of the substrate, a temperature and a time for heating the substrate according to the determined thickness of the gate insulating film, Forming the gate insulating film in the gate region according to a substrate concentration, a temperature and a time for heating the substrate;
Forming a source and a drain in accordance with a thickness of the gate insulating film; And
And adjusting a length and a width of the gate electrode according to a thickness of the gate insulating film,
In the step of forming the gate insulating film,
The gate insulating film is formed by a wet oxidation method,
Wherein the gate insulating film is formed to have a thickness greater than the thickness of the insulating layer, and the thickness of the gate insulating film is 200 nm to 1000 nm.
delete delete The method according to claim 1,
Wherein the gate insulating film is formed at a temperature of 950 to 1100 占 폚 in the step of forming the gate insulating film.
The method according to claim 1,
Wherein the gate insulating film is formed through a hydrogen gas and an oxygen gas in the step of forming the gate insulating film, and the gas pressure of the hydrogen gas and the oxygen gas is 30 mTorr to 250 mTorr.
The method according to claim 1,
In the step of adjusting the substrate concentration of the substrate, a method for producing a transistor for radiation detection sensor for the substrate concentration is adjusted in 2.7E120cm ^-3 ~ 1.5E17cm ^-3.
The method according to claim 1,
Wherein the length of the gate electrode is 0.5 占 퐉 to 15 占 퐉 and the width of the gate electrode is 800 占 퐉 in the step of forming the gate electrode.

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