Proposal of oxide ceramic LSI device for putting the brakes on global warming

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Abstract: Oxide semiconductor (OS) large-scale integration (OSLSI) uses c-axis aligned crystalline indium–
gallium–zinc oxide (CAAC-IGZO) or crystalline indium oxide (IO) including single crystal IO as its
core material (Figure 1).
With the arrival of the AI age, heat generation by mega-scale data centers and computers is accelerating global warming. Power saving is an increasingly urgent issue for humanity to put the brakes on the climate change. Servers and other equipment, however, consume more and more power with the boom of generative AI and its technological innovations. In January 2024, the International Energy Agency estimated and announced that the electricity consumption of global data centers would
reach 1000 TWh in 2026, which is 2.2 times higher than that in 2022. This is roughly equivalent to the total annual consumption in Japan. Such enormous consumption has begun to exert adverse effects on the environment and humanity in the form of climate change, which is raised as a significant issue.
Our goal is to reduce the power consumption of data centers to 1/100 by using OSLSI. OS devices exhibit extremely low off-state current and excellent on/off-state current ratio as its main characteristics. The off-state current of generally used Si field-effect transistors (FETs) is of the order of 10−10A/μm. Meanwhile, the off-state current of OS FETs is of the order of yA (10−24A)/μm to zA (10−21A)/μm and thus more than 10 orders of magnitude less than that of Si FETs (Figure 2). The on/off-state current ratio of single-crystal IO FETs is 1017, which is more than 10 orders of magnitude larger than that of Si FETs. Moreover, OS outperforms Si semiconductors in several aspects, particularly at a channel length of 15 nm or less. Thus, OS is highly expected as a semiconductor material that can replace Si. We have been working for more than 10 years on applications of OSLSI
to memories and other OSLSIs, taking advantage of the characteristics of OS.
CAAC-IGZO has already been put to practical use in OLED TVs and smartphone displays. Smartphones featuring CAAC-IGZO introduced in 2012 attracted attention for their ultra-highresolution displays and doubling of the battery time, i.e., the power consumption was half of that of conventional phones (Figure 3).
OSLSI has not been brought to the mass production yet, but we are striving towards its practical application, taking advantages of the above-described OS characteristics and our achievements in the display field. Specifically, we have already made moves to starting mass-production utilizing OSLSI technologies by the end of 2024.
The first OSLSI product will be an LSI for OLED/OS/Si displays for AR/VR applications (Figure 4). As a next step, we are developing a highly integrated vertical FET (VFET) structure and others for extremely low power consumption computers, which is our true target, with a major LSI manufacturer.
We have succeeded in the growth of IO single crystals in the vertical direction (Figure 1). This
technology will be used to mitigate an increase in power consumption due to further spread of AI.
Then, for the first time, we propose a memory, a CPU, and a GPU using OSLSIs with a threedimensional
structure (vertical structure) using single crystal IO (Figure 5-6).