Diamond is one of the most promising semiconductor materials for high power and high- frequency electronic device applications because of its exceptional mechanical, electronic and thermal properties that include wide band-gap, high breakdown electric field, high carrier mobility and high thermal conductivity. All diamond Schottky diodes and field effect transistors, as well as diamond/gallium oxide heterojunction pn diodes, were designed with Sentaurus TCAD simulations and then fabricated and tested.Schottky Barrier Diodes (SBDs) are unipolar devices formed with a potential barrier at a metal-semiconductor interface. SBDs are good for fast switching and they have a low voltage drop in the forward biased regime. Diamond based SBDs were fabricated on layered highly/lightly boron doped (p+/p- respectively) epilayers on diamond substrates. Tested diodes showed good behavior with some non-ideal characteristics. Simulations were done in Sentaurus with a non-ideal metal-insulator-semiconductor interface for the Schottky contact to get agreement of the modeled and measured diode characteristics. Diamond pn devices are promising for ultra-high voltage applications (>10kV), however diamond pn junctions have limitations due to (1) a high turn-on voltage (~5V) giving a significant on-state voltage drop and (2) n-type diamond having higher resistivity and poor ohmic contacts. An alternative n-type ultra-wide bandgap (UWBG) semiconductor with shallow donor dopants is β-Gallium Oxide (β-Ga2O3). Gallium oxide has gained significant attention due to its attractive properties like its wide bandgap (4.85eV) and high breakdown electric field in the range of 8 MV/cm. Diamond’s outstanding thermal properties can serve as a heat spreader for high power operation, which can compensate for the poor thermal conductivity of β-Ga2O3. The combination of p-type diamond and n-type Ga2O3 give the advantages of high thermal conductivity, good diamond p-type conduction, and good Ga2O3 n-type conduction. A pn junction model was developed in Sentaurus that included trap-assisted current flow at the heterojunction interface. Fabricated and tested p-type diamond and n-type Ga2O3 diodes are compared to simulations to understand the current flow mechanisms. Diamond field effect transistors (FETs) can be built in various configurations including lateral metal-semiconductor FETs (MESFETs) and vertical junction FETs (JFETs), which are designed/simulated, fabricated and tested in this work. The MESFET was tested over a wide temperature range from 300 K to 700 K with the drain current almost constant from 425-700 K. Diamond material models of carrier ionization and mobility versus temperature were used in the Sentaurus simulations. A vertical JFET was designed/simulated and the fabrication processes were developed. The JFET showed gate control of the drain current, however the device leakage currents were high due to unwanted current conduction in selective area diamond growth regions.
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