RU2646422C1 - Method of making semiconductor structure - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to the field of semiconductor device manufacturing technology, in particular to the technology of obtaining silicon films on sapphire with reduced defectiveness. In the method for manufacturing the semiconductor structure, the substrate is annealed in an atmosphere of hydrogen for 2 hours at a temperature of 1,250 °C with subsequent build-up of silicon films by pyrolysis of silane in a hydrogen atmosphere at a temperature of 1,000–1,030 °C in two stages: first, an n+-layer of silicon doped from PH₃, is grown with an impurity concentration of 10²⁰ cm^-3, with a growth rate of 5 mcm/min, then, an n-layer of silicon doped with AsH₃, is build-up with an impurity concentration of 4*10¹⁵ cm^-3, with a growth rate of 2.3 mcm/min, followed by thermal annealing at a temperature of 600 °C for 15 minutes in a hydrogen atmosphere. Next, n-channel field effect transistors and drain, source and gate electrodes are formed using standard technology.

EFFECT: proposed method for fabricating a semiconductor structure makes it possible to increase the percentage of yield of suitable devices and improve their reliability.

1 cl, 1 tbl

Description

The invention relates to the field of production technology of semiconductor devices, in particular to a technology for producing silicon films on sapphire with reduced defectiveness.

A known method of forming a semiconductor structure [Application No. 2248556 United Kingdom, MKI C23C 14/24] by growing by means of molecular beam epitaxy of semiconductor compounds of GaAs on Si or GaAs substrates. For the formation of films, gaseous substances are used, for example, Ga or In chlorides, bromides or fluorides, as well as PH3 or AsH3, purified from carbon C. A pressure of 1.33 * 10 ^-8 Pa is ensured for the process, and the substrate is heated to 650 ° C. In such semiconductor structures, due to the low technological quality of the implantation process, a large number of defects are formed that worsen the parameters of the devices.

A known method of manufacturing a semiconductor structure [Application No. 215858 Japan, MKI H01L 21/20] by growing semiconductor thin films to create structures of silicon on sapphire. For this, an amorphous silicon film is brought into contact with a flat graphite base containing point protrusions on its surface that are located at a fixed distance from each other. After that, the structure is annealed at a temperature of 500-700 ° C for the growth of the solid phase. Crystal grains grow in two opposite directions, are in contact with each other, resulting in the formation of conductive boundaries between the grains. Then the structure is oxidized. The graphite base acts as a seed for solid-phase growth.

The disadvantages of the method are:

- high leakage currents;

- high defectiveness;

- low manufacturability.

The problem solved by the invention: reducing leakage currents, ensuring manufacturability, improving instrument parameters, improving quality and increasing yield.

The problem is solved by forming an n + -layer silicon film on a sapphire substrate, followed by an increase in the silicon n layer after annealing the substrates in hydrogen for 2 hours at a temperature of 1250 ° C.

The technology of the method consists in the following: the sapphire substrate is annealed in a hydrogen atmosphere for 2 hours at a temperature of 1250 ° C to improve the surface. Then, the silicon film is grown by pyrolysis of silane in a hydrogen atmosphere at a temperature of 1000-1030 ° C in two stages: first, an n + -layer of silicon doped from PH _{3 is} grown with an impurity concentration of 10 ²⁰ cm ^-3 , with a growth rate of 5 μm / min, then An n-layer of silicon doped with AsH _{3 is} grown with an impurity concentration of 4 * 10 ¹⁵ cm ^-3 , with a growth rate of 2.3 μm / min, followed by thermal annealing at a temperature of 600 ° C for 15 minutes in a hydrogen atmosphere. Then form n-channel field effect transistors and electrodes of drain, source and gate according to standard technology.

According to the proposed method, structures were manufactured and investigated. The processing results are presented in the table.

Experimental studies have shown that the yield of suitable semiconductor devices on a batch of wafers formed in the optimal mode increased by 12.8%.

Effect: reducing leakage currents, ensuring manufacturability, improving the parameters of devices, improving the quality and increasing the percentage of yield.

The stability of the parameters over the entire operating temperature range was normal and consistent with the requirements.

The proposed method for manufacturing a semiconductor structure by forming an n + -layer silicon film on a sapphire substrate and then growing a silicon layer n, after annealing the substrates in hydrogen for 2 hours at a temperature of 1250 ° C, allows to increase the percentage of suitable devices and improve their reliability.

Claims (1)

A method of manufacturing a semiconductor structure, including the substrate, the processes of growing semiconductor films and annealing, characterized in that the substrate is annealed in hydrogen at a temperature of 1250 ° C for 2 hours, followed by silicon film pyrolysis of silane in a hydrogen atmosphere at a temperature of 1000-1030 ° C in two stages: first, an n + -layer of silicon doped from PH _{3 is} grown with an impurity concentration of 10 ²⁰ cm ^-3 and a growth rate of 5 μm / min, then an n-layer of silicon doped with AsH _{3 is} grown with an impurity concentration of 4 * 10 ¹⁵ cm ^-3 , with a growth rate of 2.3 μm / min, followed by thermal annealing at a temperature of 600 ° C for 15 minutes in a hydrogen atmosphere.