Diamond FET using high-quality polycrystalline diamond with f/sub T/ of 45 GHz and f/sub max/ of 120 GHz

Abstract

Using high-quality polycrystalline chemical-vapordeposited diamond films with large grains (∼ 100 µm), field effect transistors (FETs) with gate lengths of 0.1 µm were fabricated. From the RF characteristics, the maximum transition frequency f T and the maximum frequency of oscillation f max were ∼ 45 and ∼ 120 GHz, respectively. The f T and f max values are much higher than the highest values for singlecrystalline diamond FETs. The dc characteristics of the FET showed a drain-current density I DS of 550 mA/mm at gate-source voltage V GS of −3.5 V and a maximum transconductance g m of 143 mS/mm at drain voltage V DS of −8 V. These results indicate that the high-quality polycrystalline diamond film, whose maximum size is 4 in at present, is a most promising substrate for diamond electronic devices.Index Terms-Field effect transistor (FET), hydrogen terminated, polycrystalline diamond, RF performance.

Ultrawide‐Bandgap Semiconductors: Research Opportunities and Challenges

“…[157] All of these devices are exceeded by about 3× or more in this category by the surface-transfer-doped diamond MOSFETs reported in the last column, many of which have shown credible high-frequency performance. [81,205] The fourth materials/device properties row reports electron drift mobility, where the best-known values for lowdoped materials are given. The value for GaN represents the bulk value at a donor concentration of ≈10 16 cm −3 , which differs markedly from Hall mobilities as high as 2200 cm 2 V −1 s −1 [206] reported for 2DEGs formed in regions that have a similar background donor level.…”

Impedance analysis of Al2O3/H-terminated diamond metal-oxide-semiconductor structures

“…[1][2][3] Recently, encouraging progress, such as high cut-off frequency, has been achieved in diamond field-effect transistors (FETs) by using two-dimensional hole gas based on the ptype hydrogenated-terminated diamond surface. [4][5][6][7][8][9] Among the diamond FETs, metal-oxidesemiconductor FETs (MOSFETs) have been attracting growing interest because of the higher power handling capability. 10 For example, a high drain current density above 1 A/mm has been reported.…”

Electrolytic Treatment Characteristics of Boron-doped Nanocrystalline Diamond/Amorphous Carbon Composite Films Prepared by Coaxial Arc Plasma Deposition

“…BDD electrodes have also been used as electrodes for electrosynthesis (4) and electrochemical sensors (5) ; thus, BDD is an electrode material with numerous potential electrochemical applications. Diamond films are usually fabricated by chemical vapor deposition (CVD); they are promising for various engineering applications as electrochemical, electronic device, and hard coating materials (6,7) . However, CVD of diamond films (8,9) requires (i) a general substrate temperature of approximately 800°C or higher, (ii) pretreatment of substrates using diamond powder, which is called seeding, and (iii) the presence of molecular hydrogen.…”