JPS6057215B2 - Manufacturing method of semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to ion implantation in a compound semiconductor substrate;
The present invention provides a method for manufacturing a semiconductor device that improves the electrical characteristics of an ion-implanted layer.

When ion implantation is performed, lattice misalignment generally occurs in the semiconductor substrate, deteriorating the electrical characteristics of the formed semiconductor device.

In other words, the implanted ions collide with atoms constituting the substrate,
Atoms at lattice points in the crystal are ejected, forming interstitial vacancies. In general, implanted impurity atoms occupy most of the interstitial spaces, so heat treatment is used to replace the interstitial atoms at predetermined lattice positions, remove defects, and obtain a semiconductor device with good electrical characteristics. However, when the amount of implantation increases, it is difficult to fully recover lattice defects. Especially in compound semiconductors, it is not only difficult to fully recover lattice defects by heat treatment alone, but also replaces implanted ions at lattice positions. injection efficiency is reduced. That is, in compound semiconductors such as GaAs, defects cannot be sufficiently recovered by simple annealing treatment as in the case of silicon. The present invention proposes a new method to solve the above-mentioned drawbacks, and its main point is to generate vacancies in the lattice positions to be replaced by implanted ions in advance, then implant the ions, and then heat-treat the vacancies. The implantation efficiency is improved by replacing the implanted ions during the process, and by using an atmosphere containing inert atoms that replace the vacancies as the heat treatment atmosphere, the remaining vacancies that were not replaced by the implanted ions are removed. It is substituted to improve crystallinity.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below by describing a case where sulfur, which is an n-type impurity, is ion-implanted into a potassium arsenic (GaAs) single crystal as an example of the present invention.

Semi-insulating CaAs with a resistivity of 1 and Ω-0 to which chromium (Cr) was added was heat-treated at 7000C in vacuum for an hour to obtain A
Forms an S vacancy. Methods for forming M vacancies include heat treatment in a gallium atmosphere, or crystal formation using Ga.
It may be done in excess. Sulfur ions are implanted into the substrate in which As vacancies are formed in this way. Next, by heat treatment, the implanted ions effectively replace M ions through the As vacancies, improving implantation efficiency. The figure shows the relationship between implantation efficiency and ion implantation amount when ions are implanted after forming an M vacancy (solid line) and when ions are implanted without forming an As vacancy (dotted line) as in the conventional method. shows.

The heat treatment was carried out at 800° C. for 30 minutes in a hydrogen atmosphere. As is clear from this figure, implantation efficiency is improved by performing ion implantation after forming As vacancies. After this ion implantation, heat treatment was performed at 8000C for 30 minutes in an As atmosphere.
I went for a minute.

The As pressure is 120T! r! It is NHg. As pressure is A
It is possible to select various M pressures by changing the temperature of s. Accelerating voltage 70KeV, sulfur injection amount 10
The effective mobility of sample 13d-2 is 4500 cIt/■.
On the other hand, in the case of heat treatment without applying As pressure, 410
0C7Ff/V. It was SeC.

Note that the injection efficiency remained unchanged. However, in the case of heat treatment in an As atmosphere, it is presumed that the mobility increases because the remaining As vacancies decrease. In the above explanation, the heat treatment was performed by applying As pressure, but the same result was obtained even if heat treatment was performed by applying As pressure, and then heat treatment was performed by applying As pressure.

As is clear from the above explanation, implantation efficiency can be improved by forming vacancies to be replaced by implanted ions through heat treatment in advance and then performing ion implantation and heat treatment.Furthermore, by performing heat treatment in an As atmosphere, mobility can be improved. A semiconductor device 5 which is large in size and has excellent electrical characteristics is obtained.

In the embodiment, sulfur was described using GaAs as a compound semiconductor substrate with implanted ions, but other compound semiconductors may be used, and the same applies to implanted ions.

Furthermore, although the As atmosphere has been described as an atmosphere for replacing vacancies, any atmosphere may be used as long as it is an atmosphere containing elements constituting a compound semiconductor that replaces previously formed vacancies. As described above, in the method for manufacturing a semiconductor device of the present invention, a compound semiconductor device is heat-treated to form a vacancy at the lattice position where implanted ions are to be substituted, and impurity ions are implanted into the compound semiconductor in which the vacancy is formed. Then, the vacancies are also replaced by implanted ions, and by heat treatment in an atmosphere containing ions that replace the vacancies, the remaining vacancies that have not been replaced by the implanted ions are replaced by ions in the atmosphere. The ion implantation is performed after the vacancies to be replaced by the implanted ions are formed in advance through heat treatment, and the ion implantation efficiency is improved by heat treatment. By reducing the remaining vacancies through this process, the mobility increases, and a semiconductor device with excellent electrical characteristics and good crystallinity can be provided.

[Brief explanation of the drawing]

The figure shows a relationship curve between injection efficiency and injection amount in the present invention and the conventional method.

Claims (1)

[Claims] 1 Heat-treating the compound semiconductor device to form vacancies at lattice positions to be replaced by implanted ions, implanting impurity ions into the compound semiconductor in which the vacancies have been formed, replacing the vacancies with the implanted ions, and A method for manufacturing a semiconductor device, in which vacancies remaining without being replaced by the implanted ions are replaced by ions in the atmosphere by processing in an atmosphere containing ions that replace vacancies.