Inductively Coupled Plasma Etching of III-V Antimonides in BCl(3)/Ar and Cl(2)/Ar

Inductively coupled plasma (ICP) etching characteristics of GaSb and AIGaAsSb have been investigated in BC13/Ar and Clz/Ar plasmas. The etch rates and selectivity between GaSb and AIGaAsSb are reported as functions of plasma chemistry, ICP power, RF self-bias, and chamber pressure. It is found that physical sputtering resorption of the etch products plays a dominant role in BC13/Ar ICP etching, while in Clz/Ar plasma, the chemical reaction dominates the etching. GaSb etch rates exceeding 2 ~rnhnin are achieved in Clz/Ar plasmas with smooth surfaces and anisotropic profiles. In BC13/Ar plasmas, etch rates of 5100 Mmin and 4200 Mmin are obtained for GaSb and AIGaAsSb, respectively. The surfaces of both GaSb and AIGaAsSb etched in BC13/Ar plasmas remain smooth and stoichiometric over the entire range of plasma conditions investigated. This result is attributed to effective removal of etch products by physical sputtering. For a wide range of plasma conditions, the selectivity between GaSb and AIGaAsSb is close to unity, which is desirable for fabricating etched mirrors and gratings for Sb-based mid-IR laser diodes

Deep high-aspect ratio Si etching for advanced packaging technologies

Deep high-aspect ratio Si etching (HARSE) has shown potential application for passive self-alignment of dissimilar materials and devices on Si carriers or waferboards. The Si can be etched to specific depths and; lateral dimensions to accurately place or locate discrete components (i.e lasers, photodetectors, and fiber optics) on a Si carrier. It is critical to develop processes which maintain the dimensions of the mask, yield highly anisotropic profiles for deep features, and maintain the anisotropy at the base of the etched feature. In this paper the authors report process conditions for HARSE which yield etch rates exceeding 3 {micro}m/min and well controlled, highly anisotropic etch profiles. Examples for potential application to advanced packaging technologies will also be shown

Effects of Hydrogen Implantation into GaN

Proton implantation in GaN is found to reduce the free carrier density through two mechanisms - first, by creating electron and hole traps at around Ec-0.8eV and Ev+0.9eV that lead to compensation in both n- and p-type material, and second, by leading to formation of (AH)O complexes, where A is any acceptor (Mg, Ca, Zn, Be, Cd). The former mechanism is usefid in creating high resistivity regions for device isolation, whereas the latter produces unintentional acceptor passivation that is detrimental to device performance. The strong affinity of hydrogen for acceptors leads to markedly different redistribution behavior for implanted in n- and p-GaN due to the chemical reaction to form neutral complexes in the latter. The acceptors may be reactivated by simple annealing at 2600{degrees}C, or by electron injection at 25-150{degrees}C that produces debonding of the (AH) centers. Implanted hydrogen is also strongly attracted to regions of strain in heterostructure samples during annealing, leading to pile-up at epi-epi and epi-substrate interfaces. II? spectroscopy shows that implanted hydrogen also decorates VG, defects in undoped and n-GaN

Inductively Coupled Plasma Etching in ICl- and IBr-Based Chemistries: Part I. GaAs, GaSb and AlGaAs

High density plasma etching of GaAs, GaSb and AIGaAs was performed in IC1/Ar and lBr/Ar chemistries using an Inductively Coupled Plasma (ICP) source. GaSb and AlGaAs showed maxima in their etch rates for both plasma chemistries as a function of interhalogen percentage, while GaAs showed increased etch rates with plasma composition in both chemistries. Etch rates of all materials increased substantially with increasing rf chuck power, but rapidly decreased with chamber pressure. Selectivities > 10 for GaAs and GaSb over AlGaAs were obtained in both chemistries. The etched surfaces of GaAs showed smooth morphology, which were somewhat better with IC1/Ar than with IBr/& discharge. Auger Electron Spectroscopy analysis revealed equi-rate of removal of group III and V components or the corresponding etch products, maintaining the stoichiometry of the etched surface

GaN Metal Oxide Semiconductor Field Effect Transistors

A GaN based depletion mode metal oxide semiconductor field effect transistor (MOSFET) was demonstrated using Ga{sub 2}O{sub 3}(Gd{sub 2}O{sub 3}) as the gate dielectric. The MOS gate reverse breakdown voltage was > 35V which was significantly improved from 17V of Pt Schottky gate on the same material. A maximum extrinsic transconductance of 15 mS/mm was obtained at V{sub ds} = 30 V and device performance was limited by the contact resistance. A unity current gain cut-off frequency, f{sub {tau}}, and maximum frequency of oscillation, f{sub max} of 3.1 and 10.3 GHz, respectively, were measured at V{sub ds} = 25 V and V{sub gs} = {minus}20 V

ECR etching of group-III nitride binary and ternary films

Due to their wide band gaps and high dielectric constants, the group III-nitrides have made significant impact on the compound semiconductor community as blue and ultraviolet light emitting diodes (LEDs) and for their potential use in laser structures and high temperature electronics. Processing of these materials, in particular wet and dry etching, has proven to be extremely difficult due to their inert chemical nature. We report electron cyclotron resonance (ECR) etch rates for GaN, InN, AlN, In{sub (x)}Ga{sub (1-x)}Ni and In{sub (x)}Al{sub (1-x)}N as a function of temperature, rf-power, pressure, and microwave power. Etch conditions are characterized for rate, profile, and sidewall and surface morphology. Atomic force microscopy (AFM) is used to quantify RMS roughness of the etched surfaces. We observe consistent trends for the InAlN films where the etch rates increase with increasing concentration of In. The trends are far less consistent for the InGaN with a general decrease in etch rate as the In concentration is increased