Abstract: High electron mobility leads to better device performance and today is achieved by fabricating “gated devices” within a high-mobility two-dimensional electron gas (2DEG. However, the fabrication techniques used to form these devices lead to rapid degradation of the 2DEG quality which then can limits the mobility of the electronic devices. Accordingly, it would be beneficial to provide a process/technique which circumvents this processing and 2DEG layer damage. By exploiting a flip-chip methodology such damaging processing steps are separated to a second die/wafer which is then coupled to the 2DEG wafer. Extensions of the technique with two or more different semiconductor materials or material systems may be employed in conjunction with one or more electronic circuits to provide 2DEG enabled circuits in 2D and/or 3D stacked configurations. Further semiconductor materials providing EG elements may incorporate one or more of 2DEG, 1DEG, and “zero” DEG structures.

Abstract: Cryogenic electronics based upon semiconductive devices, superconductive devices, or a combination of the two present opportunities for a wide variety of novel, fast, and low power devices. However, such cryogenic electronics require cooling which is typically achieved through fluid refrigerants such as liquid nitrogen or liquid helium. Solid state refrigeration based upon adiabatic demagnetization in paramagnetic salts offers one alternative but requires that the solid state cooler and cryogenic electronic circuits be different physical elements. The inventors present solid state cooling for semiconductor materials including but not limited to silicon. Beneficially active electronic devices can be integrated monolithically with solid state semiconductor coolers exhibiting magnetic cooling within the whole substrate or predetermined regions of the substrate. Alternatively, active devices may be formed with semiconductor layers integral to them that exhibit magnetic cooling.

Abstract: High electron mobility leads to better device performance and today is achieved by fabricating “gated devices” within a high-mobility two-dimensional electron gas (2DEG. However, the fabrication techniques used to form these devices lead to rapid degradation of the 2DEG quality which then can limits the mobility of the electronic devices. Accordingly, it would be beneficial to provide a process/technique which circumvents this processing and 2DEG layer damage. By exploiting a flip-chip methodology such damaging processing steps are separated to a second die/wafer which is then coupled to the 2DEG wafer. Extensions of the technique with two or more different semiconductor materials or material systems may be employed in conjunction with one or more electronic circuits to provide 2DEG enabled circuits in 2D and/or 3D stacked configurations. Further semiconductor materials providing EG elements may incorporate one or more of 2DEG, 1DEG, and “zero” DEG structures.

Abstract: Cryogenic electronics based upon semiconductive devices, superconductive devices, or a combination of the two present opportunities for a wide variety of novel, fast, and low power devices. However, such cryogenic electronics require cooling which is typically achieved through fluid refrigerants such as liquid nitrogen or liquid helium. Solid state refrigeration based upon adiabatic demagnetization in paramagnetic salts offers one alternative but requires that the solid state cooler and cryogenic electronic circuits be different physical elements. The inventors present solid state cooling for semiconductor materials including but not limited to silicon. Beneficially active electronic devices can be integrated monolithically with solid state semiconductor coolers exhibiting magnetic cooling within the whole substrate or predetermined regions of the substrate. Alternatively, active devices may be formed with semiconductor layers integral to them that exhibit magnetic cooling.