At the world’s top semiconductor and electronic device technology forum IEEE IEDM held recently, two research papers on gallium oxide devices, “High Power Gallium Oxide Schottky Diode” and “Gallium Oxide Photodetector” was successfully accepted by the conference.

Among them, in terms of gallium oxide photodetectors, the team of Professor Long Shibing introduced an additional auxiliary light source to realize the control scheme of the Opposite Grating (OPG), which eased the constraint relationship between the two indicators of photodetector responsivity and response speed .

According to reports, the OPG scheme can effectively suppress the serious continuous photoconductive effect in the device, and the response speed of the device is significantly improved. The Ga2O3/WSe2 junction field effect transistor detector under this scheme exhibits negative Towards the grating effect (NPG), the threshold voltage of the device moves to the negative direction; on the contrary, the irradiation of the auxiliary light source (visible light) makes the device exhibit the positive grating effect (PPG), and the threshold voltage of the device moves to the positive direction; in the target light Under simultaneous irradiation with auxiliary light and auxiliary light, the device integrates the positive and negative opposing grating effects, but the overall performance is that the threshold voltage moves toward the negative direction.

At the same time, the auxiliary visible light introduced in the OPG regulation scheme has almost no impact on key indicators such as the light/dark current ratio and responsivity of the device. In the end, when the visible light in the OPG solution is always on, the response speed can be increased by >1200 times while only sacrificing 10.4% of the responsivity, successfully weakening the constraint relationship between the responsivity and the response speed. When the auxiliary light source is controlled by the feedback circuit to trigger only on the falling edge of the device response, the response speed will be increased by an order of magnitude without responsivity sacrifice, which has important reference significance for the improvement of the comprehensive performance of the photodetection chip .

It is reported that gallium oxide (GaO) single crystal material is the fourth generation wide bandgap semiconductor material after Si, SiC and GaN. There are 6 known crystal phases, including 5 stable phases such as α, β, γ and 1 A transient phase κ-GaO, in which the β phase is a thermodynamically stable phase. Compared with SiC and GaN, gallium oxide-based power devices have the characteristics of high withstand voltage, low loss, high efficiency, and small size. Gallium oxide is easier to manufacture than SiC and GaN because of its substrate, and because of its ultra-wide bandgap characteristics, the material can withstand higher voltage breakdown voltage and critical electric field, making it extremely suitable for ultra-high power components. potential.

Gallium oxide was previously used in the field of optoelectronics. Until 2012, 80% of the research institutes in the world have turned their research direction to the application of power devices.

From the perspective of the market, gallium oxide has just entered the initial commercial application stage from the research and development stage. The United States, Japan, Europe, South Korea, mainland China and Taiwan are all developing gallium oxide wafers and devices. Among them, the United States Kyma Technology (Kyma) , Kyoto University FLOSFIA and Japanese start-up Novel Crystal are the market leaders.

In China, the current domestic GaO industrial chain links are very weak, the number of foundries available is zero, and there are several epitaxy companies and substrate companies, but the scale is very small and has not yet reached mass production. Atecom Technology, a Taiwanese silicon ingot and wafer manufacturer and seller, also deals in gallium oxide. In mainland China, Xiamen Pauway Advanced Materials (PAM-XIAMEN) is in the early stages of developing the technology.

Under this circumstance, in order to promote the development of the domestic gallium oxide industry, the Ministry of Science and Technology of China included gallium oxide in the “14th Five-Year Key R&D Plan” this year. Shanghai Institute of Optics and Mechanics, Beijing Gallium Group Technology, Hangzhou Fujia Gallium Industry and other units are the main force to overcome the problem of gallium oxide materials, making the fourth-generation semiconductors gain wider attention.

It is worth noting that on May 10, Hangzhou Science and Technology Innovation Center of Zhejiang University successfully prepared a 2-inch (50.8 mm) gallium oxide wafer using a new technology route for the first time, and the 2-inch gallium oxide wafer grown using this technology with completely independent intellectual property rights Gallium oxide wafer is the first in the world.

On December 9th, Beijing Mingga Semiconductor Co., Ltd. successfully prepared a high-quality 4-inch (001) main surface gallium oxide (β-Ga2O3) single crystal using the guided mode method, and completed a breakthrough in the 4-inch gallium oxide wafer substrate technology. And conducted repeated experiments, becoming the first industrialized company in China to master the 4-inch (001) phase single crystal substrate growth technology of the fourth-generation semiconductor gallium oxide material. The company also completed a round of financing of nearly 100 million yuan on June 30, which will be mainly used for the expansion and research and development of the gallium oxide project, and is expected to build the first domestic crystal growth, crystal processing, and thin film epitaxy by the end of 2023. The complete industry line of gallium oxide.

Regarding the future of gallium oxide, Hao Yue, an academician of the Chinese Academy of Sciences, said that gallium oxide materials are one of the materials most likely to shine in the future. In the next 10 years or so, gallium oxide devices may become competitive power electronic devices , will directly compete with SiC devices. It is generally believed in the industry that gallium oxide is expected to replace silicon carbide and gallium nitride as the representative of a new generation of semiconductor materials. At present, semiconductor companies in various countries are scrambling to deploy, and gallium oxide is gradually becoming a rising star in the field of semiconductor materials.