JPH02230772A - Structure of MIS type semiconductor device - Google Patents

Abstract

PURPOSE:To obtain an MIS type semiconductor device wherein effective mobility is high and characteristics are improved by a method wherein impurity atom and defect level in the vicinity of a semiconductor surface under an insulating film are made electrically inactive by introducing atomic state hydrogen. CONSTITUTION:Regions turning to a source and a drain are patterned on an undoped bulk semiinsulative GaAs by using photo resist; silicon ion turning to N-type impurity is implanted; then the photo resist is exfoliated. After AlN is deposited as a protecting film for heat treatment and activating heat treatment is performed, the protecting film is exfoliated. After AlN for a gate insulating film is deposited and Pd is vapor deposited, a gate part is formed by patterning. In order to introduce hydrogen atom, heat treatment at 270 deg.C in a hydrogen air flow is performed for three hours. As the result of said treatment, atomic state hydrogen introduced into semiconductor makes defect and impurity electrically inactive, thereby obtaining excellent interface characteristics.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the structure of an MIS type semiconductor device, and more particularly to the structure of a MIS type semiconductor device that utilizes conduction of carriers induced at the interface between an insulator and a semiconductor. Regarding.

[Prior Art] MIS type semiconductor devices, which operate by conduction of carriers induced at the interface between an insulator and a semiconductor, have a conduction type of the semiconductor that is the opposite to that of transport carriers, or a semi-insulating type that is normally off type. do.

For this reason, it is necessary to limit the manufacturing method or manufacturing conditions of the semiconductor layer. For example, when manufacturing an n-type MIs field transistor using gallium arsenide (hereinafter referred to as GaAs) as the semiconductor layer, residual carriers A bulk crystal with a deep compensation level introduced or a weak p-type epitaxial crystal is used. Of these, from the viewpoint of crystallinity and uniformity that determine carrier mobility, the epitaxial crystal is more desirable.

In the actual manufacturing process of MIS type semiconductor devices, it is necessary to form highly doped regions in the semiconductor substrate as described above in order to establish ohmic contact between the source and drain, and planar type devices usually require ion implantation. used. If the heat resistance of the MIS system is sufficiently high, the above process can be performed after forming the gate part, but if the electrical characteristics of the MIS system deteriorate due to activation heat treatment after ion implantation, insulation It is necessary to form a high concentration region in advance before body film deposition. In the latter case, it is necessary to remove the degraded layer formed on the semiconductor surface by the high concentration region forming process before depositing the insulating film.

[Problem to be solved by the invention] In a MIS type semiconductor device that utilizes conduction of accumulated carriers at an insulator-semiconductor interface, GaAs is used as a semiconductor.
When using compound semiconductors such as, there are problems such as a high concentration of defect levels at the insulating film-semiconductor interface, which limits the movement range of the surface potential and low carrier mobility at the interface. It becomes.

Furthermore, in this type of MIS type semiconductor device, there is a limit to the concentration of residual impurities in the semiconductor as described above, but on the other hand, when using an organometallic vapor phase epitaxial crystal, it is possible to reduce the concentration of residual carriers without adding any additives. In order to keep it low, it is necessary to reduce the supply ratio of group V raw materials to group (2) raw materials, which poses the problem of making it difficult to achieve good surface morphology.

Moreover, in order to improve the crystallinity, it is necessary to set the growth temperature higher, and in this case, there is also the problem that the residual carrier concentration tends to increase. On the other hand, although the method of introducing compensation impurities can reduce the residual carrier concentration, there is a problem in that the number of carrier scattering centers increases and the mobility decreases.

Furthermore, when removing a deteriorated layer generated during the process by chemical etching due to the circumstances described in the conventional technology, there is an inherent limit to the thickness of the semiconductor layer that can be removed, and the processing state of the semiconductor surface after etching is controlled. There was a problem that I couldn't do it.

The present invention has been made to solve the conventional problems as described above, and an object of the present invention is to provide a structure of a semiconductor device with high effective mobility and improved characteristics.

[Means for Solving the Problems] The present invention provides an MIS type semiconductor device structure in which an insulating film is formed on a semiconductor, in which impurity atoms and defect units near the semiconductor surface under the insulating film are reduced by the introduction of atomic hydrogen. This is a structure of a MIS type semiconductor device characterized by being electrically inactivated.

In the present invention, the semiconductor layer on which the insulating film is formed may be a bulk crystal grown by an additive-free liquid confinement pulling method, or a hulk crystal grown by an additive-free vapor phase epitaxial growth method. It may also be an epitaxially grown crystal grown.

In particular, when an epitaxially grown crystal is used, it is possible to inactivate residual impurities in the channel region, so it is possible to inactivate residual impurities in the channel region. There is no need to limit the supply ratio, and growth conditions optimized only from the viewpoint of crystallinity can be selected.

[Operation 1] The present invention utilizes the phenomenon that atomic hydrogen introduced into a semiconductor electrically inactivates defects and impurities. When defects and impurities are electrically inactivated, the substantial residual defect concentration and residual impurity concentration at the insulator-semiconductor interface are reduced, and good interface characteristics can be obtained. Therefore, even in a GaAS-based MIS type device, for example, device characteristics can be improved in terms of surface potential pinning and carrier mobility.

[Example 1 Examples of the present invention will be described below.

In the first embodiment, an example will be described in which a GaAS substrate is used and an MIS type field effect transistor (MISFET) is manufactured by depositing aluminum nitride (ΔIN) as an insulating film using a trimethylaluminum-hydrazine-based raw material.

First, regions that will become sources and trains are patterned using photoresist on bulk doped-free semi-insulating GaAS grown by the liquid-sealed pulling method, and silicon (S i ) ions, which will become n-type impurities, are exposed to energy 100.
After implantation under the conditions of keV and dose setting of 2×10 14 cm −2 , the photoresist was peeled off. AI as a heat treatment protective film! Deposit N for 1000 hours and perform activation heat treatment for 950 hours.
After the test was carried out at ℃ for 20 minutes, the protective film was peeled off. Next, 80 OA of ΔNN for the gate insulating film was deposited, and 500 OA of Pd was deposited using the resistance heating method under a vacuum with a back pressure of 1×1 and 7 Torr.
After 0 A vapor deposition, patterning was performed to form a gate portion.

Then, in order to introduce hydrogen atoms, 270
Heat treatment was performed at °C for 3 hours. Finally, gold germanium nickel (AuGeNi) is used as the source and train region electrodes.
) was formed using a lift-off method to form a MISFET.

The MISFET fabricated in this example exhibited electron storage type operation, and the effective mobility of the obtained device in the current saturation region was 2400 cm2 V-1 sec-1 at room temperature, and the device was inactivated by hydrogen atoms. 20 compared to without
% mobility improvement was observed.

In the second example, the semiconductor of the first example was replaced with bulk semi-insulating GaAS, and was replaced with epitaxial GaAs grown on it by a chemical vapor deposition method (MOCVD method) using an organic metal as a raw material. . At this time, the growth temperature was 750'C.
, 2000 crystals were grown with a V/III ratio of 150. After this, M was grown using the same process as in the first example.
An ISFET was fabricated.

If hydrogen atoms were not introduced, the semiconductor layer in the channel region had n-type conductivity, resulting in a normally-on type device, resulting in a depletion layer modulation type device. On the other hand, when hydrogen atoms are introduced, the electron accumulation operation is similar to that of the first embodiment, and by using the semiconductor layer in the channel portion as an epitaxial growth layer, the first embodiment The effective mobility increases compared to the example, 2500c
m2 V-1 sec-1 was obtained. This result is more than 10% higher than the MISFET with the highest effective mobility produced by the conventional method.

Note that although GaAS was used as the semiconductor in the above embodiments, the intrinsic carrier concentration was low to a practically unacceptable level;
Moreover, other materials may be used as long as they are semiconductors in which impurity inactivation by hydrogen atoms occurs. Further, as the gate insulator, a material other than A2N used here may be used.

[Effects of the Invention] As described above, according to the present invention, a structure of a MIS type semiconductor device with high effective mobility and improved characteristics can be obtained.

Claims (1)

[Claims] (1) In the structure of a MIS type semiconductor device in which an insulating film is formed on a semiconductor, impurity atoms and defect levels near the semiconductor surface under the insulating film are electrically inactivated by the introduction of atomic hydrogen. A structure of a MIS type semiconductor device characterized by the following.